[top]
000
FXUS65 KPSR 070310
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
810 PM MST SAT SEP 6 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT THROUGH SUNDAY. EARLY NEXT WEEK A LOW PRESSURE SYSTEM
WILL ENCROACH ON THE DESERT SOUTHWEST RESULTING IN INCREASING
CLOUDS...COOLER TEMPERATURES...AND INCREASED CHANCES FOR MOUNTAIN
THUNDERSTORMS MAINLY ACROSS ARIZONA. THE LOW PRESSURE SYSTEM WILL
REMAIN A CONSTANT WEATHER FEATURE THROUGH THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
MOSTLY CLEAR SKIES COVERED THE FORECAST AREA (SOUTHEAST CA TO SOUTH
CENTRAL AZ) AT 03Z...BUT A FEW SPOTTY MID CLOUDS REMAINED. SCATTERED
CLOUDS IN SOUTHERN AZ SATURDAY AFTERNOON WERE THE LEADING EDGE OF
MUCH DEEPER MONSOON MOISTURE IN NORTHWEST MEXICO. THERE WERE EVEN
ONE OR TWO HIGH CLOUD BASED THUNDERSTORMS NOTED SATURDAY AFTERNOON
JUST SOUTHEAST OF TUCSON...AND OVER THE WHITE MOUNTAINS.
AS MENTIONED ABOVE...MOISTURE IS MUCH DEEPER IN MEXICO. BASED ON THE
PHOENIX AND TUCSON BALLOON SOUNDINGS...IN ORDER TO DEVELOP
MEANINGFUL C.A.P.E. FOR THUNDERSTORMS...700 MB DEWPOINTS WOULD NEED
TO INCREASE TO 2 DEGREES C ...AND 800 MB DEWPOINTS AROUND 4 C. THOSE
VALUES WERE NOT TO FAR AWAY IN MEXICO.
AS THE PREVIOUS DISCUSSION BELOW MENTIONS...A LARGE PACIFIC TROF IS
FORECAST TO MOVE INTO THE ENTIRE WESTERN U.S. BY TUESDAY MORNING.
THIS WILL ENABLE BACKING LOW LEVEL SOUTH WINDS FROM MEXICO...AND A
POTENTIAL RESURGENCE OF MONSOON MOISTURE NORTH INTO AZ LATE
MONDAY...BUT PARTICULARLY TUE. INCREASING JET STREAM WINDS AND
COOLER MID LEVEL TEMPERATURES PORTEND A VERY UNSTABLE ATMOSPHERE
TUESDAY FOR INCREASING THUNDERSTORMS...POSSIBLY SEVERE IN CENTRAL
AND NORTHERN AZ.
OTHERWISE...DRY WEATHER WILL CONTINUE OVER THE FORECAST AREA THROUGH
MONDAY. CURRENT FORECASTS REFLECT THIS...AND ALSO REFLECT AN
INTRODUCTION OF THUNDERSTORMS BACK INTO THE FORECAST FOR SOUTH
CENTRAL AZ TUESDAY. NO FORECAST UPDATES NEEDED. PREVIOUS
DISCUSSION BELOW STILL APPLIES.
ADDITIONALLY...THE EXCESSIVE HEAT WARNING ISSUED EARLIER TODAY FOR
SOUTHEAST CA EXPIRED AT 03Z. FORECAST AFTERNOON TEMPERATURES ON
SUNDAY ARE BELOW WARNING CRITERIA.
PREVIOUS DISCUSSION...
MONSOON IS ALREADY SHOWING SIGNS OF RETURNING...AS CU (ALBEIT
LOW-TOPPED) HAS DEVELOPED ALONG THE MOGOLLON RIM AND THE HIGHER
TERRAIN OF SOUTHERN AZ. ENVIRONMENT GENERALLY REMAINS TOO DRY FOR
THUNDERSTORMS THIS AFTERNOON. THIS IS REFLECTED IN LOCAL K-INDICES
WHICH ARE ONLY PEAKING AROUND 20 ACROSS MUCH OF THE FORECAST AREA.
HOWEVER...LATEST NAM-WRF SUGGESTS DEEPER MOISTURE CURRENTLY OVER
CHIHUAHUA WILL LIFT NORTHWESTWARD INTO SE AZ SUN. THIS SHOULD HELP
TO PRIME THE LOWER LEVELS BY MON ACROSS SOUTH-CENTRAL AZ WITH
DEWPOINTS IN THE LOWER-MID 50S ACROSS THE LOWER DESERTS.
MODELS IN GENERALLY GOOD AGREEMENT THAT AN AREA OF LOW PRESSURE WILL
SLIDE SLOWLY SOUTHWARD DOWN THE CA COAST THIS WEEK. THIS WILL SET UP
A SOUTHWESTERLY FLOW...FAVORING THE HIGHER TERRAIN (EVEN ACROSS THE
SOUTHWEST DESERTS) OF THE FORECAST AREA FOR SHOWER AND THUNDERSTORM
ACTIVITY. WESTERN EXTENSION OF THE SEMI-PERMANENT ATLANTIC RIDGE IS
EXPECTED TO DRIFT WESTWARD AS TROPICAL CYCLONE IKE MOVES WESTWARD
TOWARDS THE FL STRAITS AND POSSIBLY INTO THE GULF OF MEXICO. MOIST
SUBTROPICAL FEED WILL CONTINUE ACROSS THE DESERT SOUTHWEST THROUGH
MIDWEEK AS THE SOUTHWESTERLY FLOW STRENGTHENS BETWEEN THE EASTERN
PACIFIC LOW (WHICH MAY ULTIMATELY CUT OFF) AND A BUILDING RIDGE
ACROSS MEXICO.
BEST CHANCE FOR PRECIPITATION IN THE VALLEY APPEARS TO BE LATE IN
THE WEEK AS THE LOW-LEVEL FLOW ACQUIRES MORE OF AN EASTERLY
COMPONENT AROUND THE RIDGE...CENTERED GENERALLY ACROSS THE FOUR
CORNERS OR EAST OF THE AREA. DISCERNIBLE THREAT FOR THUNDERSTORMS
WILL ALSO EXIST ACROSS THE LOWER CO RIVER VALLEY (PER THE LATEST
ECMWF) AS THE CA LOW EVENTUALLY SLIDES EASTWARD WHILE DISSIPATING
NEXT WEEKEND.
MADE SOME MINOR ADJUSTMENTS TO THE DIGITAL DATABASE...MAINLY TO
INCREASE POPS THROUGH THE WEEK. TEMPERATURE-WISE...INCREASE IN
MOISTURE COMBINED WITH DECREASING THICKNESSES WILL RESULT IN COOLER
TEMPS...THOUGH STILL REMAINING ABOVE AVERAGE THROUGH AT LEAST THU OR
FRI.
&&
.AVIATION...
SOUTHEAST CA TO SOUTH CENTRAL AZ...INCLUDING KPHX...KIPL...KIWA...
KNYL...AND KBLH AIRFIELDS. MOSTLY CLEAR SKIES AND LIGHT WINDS ARE
EXPECTED THROUGH AT LEAST 04Z MON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES CAN BE EXPECTED
MONDAY...BEFORE A GRADUAL COOLING TREND WILL BRING TEMPERATURES TO
NEAR SEASONAL NORMALS BY WEDNESDAY. THE ATMOSPHERE WILL REMAIN
RELATIVELY DRY...WITH AFTERNOON RH VALUES IN THE TEENS MONDAY AND
TUESDAY...RISING A BIT BY WEDNESDAY INTO THE UPPER TEENS AND LOWER
TWENTIES ACROSS THE LOWER DESERTS. WINDS WILL GENERALLY BE LIGHT
WITH ONLY A FEW AFTERNOON GUSTS. A WEAK LOW PRESSURE SYSTEM WILL
DEVELOP OFF THE COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT
CHANCE OF THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...VASQUEZ/HIRSCH
AVIATION...VASQUEZ
FIRE WEATHER...ROGERS
[top]
000
FXUS65 KFGZ 062159
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
300 PM MST SAT SEP 6 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...SUNNY SKIES PREVAILED ACROSS ARIZONA THIS AFTERNOON.
THE AIR MASS REMAINS DRY AND WARM ACROSS THE REGION TODAY...SO HIGH
TEMPERATURES TODAY HAVE BEEN RUNNING 5-8 DEGREES ABOVE NORMAL. EVEN WITH
THE DRY BOUNDARY LAYER...DEEP MIXING THIS AFTERNOON HAS RESULTED IN
SOME HIGH-BASED CUMULUS OVER THE MTNS...WITH A VERY SLIM CHANCE OF A
SHOWER OVER THE WHITE MTNS THROUGH LATE AFTERNOON.
THE WEATHER PATTERN BEGINS TO CHANGE BY SUNDAY AS THE DRYING
NORTHWEST FLOW PRODUCED BY THE CENTRAL U.S. TROUGH DIMINISHES. A
WEAK TROUGH WILL PERSIST OFF THE WEST COAST...WHILE A RIDGE EXPANDS
WESTWARD ACROSS MEXICO. THIS GENERAL PATTERN IS FORECAST TO CONTINUE
THROUGH MUCH OF NEXT WEEK. THE FLOW ACROSS ARIZONA WILL TURN FROM
THE SOUTH OR SOUTHWEST...AND SHOULD IMPORT ENOUGH MOISTURE INTO THE
STATE FOR A CHANCE OF SHOWERS AND THUNDERSTORMS...STARTING WITH LOW
CHANCES SUNDAY...THEN INCREASING FOR MONDAY AND TUESDAY. NOT
EXPECTING ANYTHING TOO SIGNIFICANT AT THIS POINT...MAINLY DUE TO
LIMITED MOISTURE AND INSTABILITY. AN ADDITIONAL MOISTURE SURGE COULD
OCCUR IF AND WHEN THE WEST COAST CUTOFF LOW MOVES EASTWARD TOWARD
THE STATE...BUT TIMING THIS FEATURE WILL BE DIFFICULT WITH CURRENT
MODEL RUNS SHOWING DIFFERING SOLUTIONS. WE WILL KEEP LOW STORM
CHANCES IN THE FORECAST THROUGH NEXT WEEKEND BASED ON THIS
UNCERTAINTY.
&&
.AVIATION...FOR THE 00Z PACKAGE...VFR CONDITIONS AND LIGHT SURFACE
WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24 HOURS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
TUESDAY THROUGH THURSDAY...THERE WILL BE SLIGHT CHANCES OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN OF
NORTHERN ARIZONA THROUGH THE PERIOD WITH THE GREATEST CHANCES FOR
PRECIPITATION ALONG THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JJ
AVIATION/FIRE WX.....KD
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KPSR 062138
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
240 PM MST SAT SEP 6 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT THROUGH SUNDAY. EARLY NEXT WEEK A LOW PRESSURE SYSTEM
WILL ENCROACH ON THE DESERT SOUTHWEST RESULTING IN INCREASING
CLOUDS...COOLER TEMPERATURES...AND INCREASED CHANCES FOR MOUNTAIN
THUNDERSTORMS MAINLY ACROSS ARIZONA. THE LOW PRESSURE SYSTEM WILL
REMAIN A CONSTANT WEATHER FEATURE THROUGH THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
MONSOON IS ALREADY SHOWING SIGNS OF RETURNING...AS CU (ALBEIT
LOW-TOPPED) HAS DEVELOPED ALONG THE MOGOLLON RIM AND THE HIGHER
TERRAIN OF SOUTHERN AZ. ENVIRONMENT GENERALLY REMAINS TOO DRY FOR
THUNDERSTORMS THIS AFTERNOON. THIS IS REFLECTED IN LOCAL K-INDICES
WHICH ARE ONLY PEAKING AROUND 20 ACROSS MUCH OF THE FORECAST AREA.
HOWEVER...LATEST NAM-WRF SUGGESTS DEEPER MOISTURE CURRENTLY OVER
CHIHUAHUA WILL LIFT NORTHWESTWARD INTO SE AZ SUN. THIS SHOULD HELP
TO PRIME THE LOWER LEVELS BY MON ACROSS SOUTH-CENTRAL AZ WITH
DEWPOINTS IN THE LOWER-MID 50S ACROSS THE LOWER DESERTS.
MODELS IN GENERALLY GOOD AGREEMENT THAT AN AREA OF LOW PRESSURE WILL
SLIDE SLOWLY SOUTHWARD DOWN THE CA COAST THIS WEEK. THIS WILL SET UP
A SOUTHWESTERLY FLOW...FAVORING THE HIGHER TERRAIN (EVEN ACROSS THE
SOUTHWEST DESERTS) OF THE FORECAST AREA FOR SHOWER AND THUNDERSTORM
ACTIVITY. WESTERN EXTENSION OF THE SEMI-PERMANENT ATLANTIC RIDGE IS
EXPECTED TO DRIFT WESTWARD AS TROPICAL CYCLONE IKE MOVES WESTWARD
TOWARDS THE FL STRAITS AND POSSIBLY INTO THE GULF OF MEXICO. MOIST
SUBTROPICAL FEED WILL CONTINUE ACROSS THE DESERT SOUTHWEST THROUGH
MIDWEEK AS THE SOUTHWESTERLY FLOW STRENGTHENS BETWEEN THE EASTERN
PACIFIC LOW (WHICH MAY ULTIMATELY CUT OFF) AND A BUILDING RIDGE
ACROSS MEXICO.
BEST CHANCE FOR PRECIPITATION IN THE VALLEY APPEARS TO BE LATE IN
THE WEEK AS THE LOW-LEVEL FLOW ACQUIRES MORE OF AN EASTERLY
COMPONENT AROUND THE RIDGE...CENTERED GENERALLY ACROSS THE FOUR
CORNERS OR EAST OF THE AREA. DISCERNIBLE THREAT FOR THUNDERSTORMS
WILL ALSO EXIST ACROSS THE LOWER CO RIVER VALLEY (PER THE LATEST
ECMWF) AS THE CA LOW EVENTUALLY SLIDES EASTWARD WHILE DISSIPATING
NEXT WEEKEND.
MADE SOME MINOR ADJUSTMENTS TO THE DIGITAL DATABASE...MAINLY TO
INCREASE POPS THROUGH THE WEEK. TEMPERATURE-WISE...INCREASE IN
MOISTURE COMBINED WITH DECREASING THICKNESSES WILL RESULT IN COOLER
TEMPS...THOUGH STILL REMAINING ABOVE AVERAGE THROUGH AT LEAST THU OR
FRI.
&&
.AVIATION...
ASIDE FROM A FEW FLAT CUMULUS CLOUDS ACROSS THE REGION...SKIES WILL
BECOME GENERALLY CLEAR LATER THIS EVENING AT ALL TAF SITES. LATER
TONIGHT THERE MAY BE SOME MID-LEVEL CLOUDINESS FORM GENLY AOA 15K
MSL...BUT NO BROKEN DECKS ARE ANTICIPATED ATTM. EXPECT NORMAL WIND
TRENDS ALL LOCATIONS THROUGH 00Z MONDAY...WITH SPEEDS GENLY LESS
THAN 10KTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES CAN BE EXPECTED
MONDAY...BEFORE A GRADUAL COOLING TREND WILL BRING TEMPERATURES TO
NEAR SEASONAL NORMALS BY WEDNESDAY. THE ATMOSPHERE WILL REMAIN
RELATIVELY DRY...WITH AFTERNOON RH VALUES IN THE TEENS MONDAY AND
TUESDAY...RISING A BIT BY WEDNESDAY INTO THE UPPER TEENS AND LOWER
TWENTIES ACROSS THE LOWER DESERTS. WINDS WILL GENERALLY BE LIGHT
WITH ONLY A FEW AFTERNOON GUSTS. A WEAK LOW PRESSURE SYSTEM WILL
DEVELOP OFF THE COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT
CHANCE OF THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ020-021-
025-026.
CA...EXCESSIVE HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR CAZ031>033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...ESTLE
FIRE WEATHER...ROGERS
[top]
000
FXUS65 KTWC 062056
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
155 PM MST SAT SEP 6 2008
.SYNOPSIS...A TROUGH OF LOW PRESSURE ALONG THE CALIFORNIA COAST WILL
BRING A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS MAINLY
TO AREAS EAST OF TUCSON DURING THE UPCOMING WEEK. HOT CONDITIONS
SUNDAY FOLLOWED BY BELOW NORMAL DAYTIME TEMPERATURES DURING THE
MIDDLE AND LATTER PART OF THE NEW WEEK.
&&
.DISCUSSION...WEAK LOW PRESSURE SYSTEM OFF THE SRN CALIFORNIA COAST
WILL BRING A GRADUAL INCREASE IN MAINLY MID-LEVEL MOISTURE ACROSS SE
AZ TONIGHT INTO TUE. PRECIP-FREE CONDITIONS EXPECTED TONIGHT WITH
THE EXCEPTION OF A FEW SHOWERS AND THUNDERSTORMS THIS EVENING NEAR
THE INTERNATIONAL BORDER OF COCHISE AND SANTA CRUZ COUNTIES AS WELL
AS THE TOHONO OODHAM NATION. SLIGHT CHANCE OF AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS ACROSS ERN ZONES SUN-TUE.
THEREAFTER...06/12Z GFS DEPICTED QUASI-STATIONARY CLOSED-LOW JUST
OFF THE CENTRAL CALIFORNIA COAST WED-THUR WITH RIDGE AMPLIFICATION
OVER THE SRN ROCKIES. HOWEVER...06/12Z ECMWF DEPICTED POSITIVE-TILT
OPEN WAVE TROUGH OVER THE WRN CONUS WED...THEN WEAKER CLOSED-LOW
WELL OFF THE SRN CALIFORNIA COAST THUR-FRI. GFS SUBSEQUENTLY
IMPORTED CONSIDERABLY MORE MOISTURE ACROSS SRN AZ DURING THE MIDDLE
AND LATTER PART OF THE UPCOMING WEEK VERSUS THE ECMWF SOLUTION.
GIVEN THESE DIFFERENCES...HAVE OPTED TO MAKE ONLY VERY MINOR
MODIFICATIONS TO THE EXISTING GRIDDED DATA POP FIELDS DURING THE
WED-SAT PERIOD. WILL REFLECT A SLIGHT CHANCE OF AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS TUCSON METRO AREA EWD WED-FRI WITH
PRECIP-FREE CONDITIONS WEST. FOR NOW WILL OPT FOR LOW-GRADE POPS ERN
SECTIONS SAT WITH DRY CONDITIONS TUCSON METRO AREA WWD. ABOVE NORMAL
DAYTIME HIGH TEMPS SUN-MON...THEN SOME COOLING DURING THE MIDDLE AND
LATTER PART OF THE UPCOMING WEEK.
&&
.AVIATION...FEW-SCATTERED CUMULOFORM CLOUDS WITH BASES AROUND 9-12K
FT AGL INTO THIS EVENING. SLIGHT CHANCE OF TSRA/SHRA NEAR THE
INTERNATIONAL BORDER ENDING AROUND 03Z. MOSTLY CLEAR OVERNIGHT INTO
SUNDAY MORNING. SLIGHT CHANCE OF TSRA EAST AND SOUTH OF KTUS SUNDAY
AFTERNOON AND EVENING. LIGHT SURFACE WINDS TONIGHT INTO SUNDAY.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
000
FXUS65 KFGZ 061658
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
955 AM MST SAT SEP 6 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...SUNNY SKIES PREVAIL ACROSS ARIZONA THIS MORNING. THE
AIR MASS REMAINS DRY AND WARM ACROSS THE REGION TODAY...SO WE EXPECT
MAINLY SUNNY SKIES WITH AFTERNOON TEMPERATURES RUNNING 5-8 DEGREES
ABOVE NORMAL. EVEN WITH THE DRY BOUNDARY LAYER...DEEP MIXING THIS
AFTERNOON WILL RESULT IN SOME HIGH-BASED CUMULUS OVER THE
MTNS...WITH A VERY SLIM CHANCE OF A SHOWER OVER THE WHITE MTNS.
THE WEATHER PATTERN BEGINS TO CHANGE BY SUNDAY AS THE DRYING
NORTHWEST FLOW PRODUCED BY THE CENTRAL U.S. TROUGH DIMINISHES. A
WEAK TROUGH WILL PERSIST OFF THE WEST COAST...WHILE A RIDGE EXPANDS
WESTWARD ACROSS MEXICO. THIS GENERAL PATTERN IS FORECAST TO CONTINUE
THROUGH MUCH OF NEXT WEEK. THE FLOW ACROSS ARIZONA WILL TURN FROM
THE SOUTH OR SOUTHWEST...AND SHOULD IMPORT ENOUGH MOISTURE INTO THE
STATE FOR A CHANCE OF SHOWERS AND THUNDERSTORMS...STARTING WITH LOW
CHANCES SUNDAY...THEN INCREASING FOR MONDAY AND TUESDAY. NOT
EXPECTING ANYTHING TOO SIGNIFICANT AT THIS POINT...MAINLY DUE TO
LIMITED MOISTURE AND INSTABILITY. AN ADDITIONAL MOISTURE SURGE COULD
OCCUR IF AND WHEN THE WEST COAST CUTOFF LOW MOVES EASTWARD TOWARD
THE STATE...BUT TIMING THIS FEATURE WILL BE DIFFICULT WITH CURRENT
MODEL RUNS SHOWING DIFFERING SOLUTIONS. WE WILL KEEP LOW STORM
CHANCES IN THE FORECAST THROUGH NEXT WEEKEND BASED ON THIS
UNCERTAINTY.
&&
.AVIATION...FOR THE 18Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
MONDAY THROUGH WEDNESDAY...THERE WILL BE SLIGHT CHANCES OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN OF
NORTHERN ARIZONA THROUGH THE PERIOD WITH THE GREATEST CHANCES OF
THUNDERSTORMS ALONG THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JJ
AVIATION/FIRE WX.....KD
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KTWC 061654
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
950 AM MST SAT SEP 6 2008
.SYNOPSIS...DRY CONDITIONS ACROSS SOUTHEAST ARIZONA TODAY EXCEPT FOR
ISOLATED THUNDERSTORMS NEAR THE INTERNATIONAL BORDER THIS AFTERNOON
AND EVENING. A WEAK LOW PRESSURE SYSTEM WILL REMAIN OFF THE SOUTHERN
CALIFORNIA COAST EARLY NEXT WEEK. THIS SYSTEM WILL BRING INCREASED
CLOUDINESS AND A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
DURING THE UPCOMING WEEK.
&&
.DISCUSSION...CLEAR SKIES ACROSS SE AZ THIS MORNING WITH THE
EXCEPTION OF A FEW CUMULOFORM CLOUDS MOVING NWWD ACROSS FAR WRN PIMA
COUNTY. DEWPOINTS VALID 16Z WERE IN THE MID 40S-LOWER 50S AND THESE
TEMPS WERE NEARLY 2-5 DEGS LOWER VERSUS 24 HOURS AGO. SURFACE TEMPS
VALID 16Z WERE NEARLY IDENTICAL TO THIS TIME FRI. 06/12Z KTWC
SOUNDING DEPICTED A FAIRLY DRY PROFILE...WITH PRECIP WATER VALUE
NEAR 0.60 INCH. ELY FLOW IN THE SURFACE-500 MB LAYER WITH WLY FLOW
ABOVE 500 MB.
WEAK LOW PRESSURE SYSTEM OFF THE SRN CALIFORNIA COAST EXPECTED TO
BRING A GRADUAL INCREASE IN MAINLY MID-LEVEL MOISTURE ACROSS THE
AREA SUN AND CONTINUING INTO THE MIDDLE OF THE UPCOMING WEEK...AT
LEAST. INHERITED GRIDDED DATA FIELDS DEPICT LOW-GRADE POPS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF TUCSON SUN AFTERNOON AND EVENING.
LITTLE CHANGE IN THE LARGE SCALE PATTERN SHOULD JUSTIFY A SLIGHT
CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS FOR AREAS
SOUTH AND EAST OF TUCSON DURING THE MON-WED PERIOD. THEREAFTER...
NWP SOLUTIONS HAVE BEEN SLIGHTLY MORE AGGRESSIVE IN DEVELOPING A
CUT-OFF LOW JUST OFF THE CENTRAL CALIFORNIA COAST DURING THE LATTER
PART OF THE WEEK. MID-LEVEL MOISTURE EXPECTED TO BE SUFFICIENT FOR A
CONTINUED SLIGHT CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ACROSS ERN SECTIONS. DAYTIME HIGH TEMPS REMAINING
ABOVE SEASONAL NORMALS TODAY-MON...THEN SOME COOLING DURING THE
MIDDLE AND LATTER PART OF THE UPCOMING WEEK.
&&
.AVIATION...MOSTLY CLEAR SKIES ACROSS SE AZ THROUGH TONIGHT ALONG
WITH LIGHT DIURNALLY DRIVEN SURFACE WINDS. SLIGHT CHANCE OF TSRA
NEAR THE INTERNATIONAL BORDER DURING THE 19Z-03Z PERIOD. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 061624
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
925 AM MST SAT SEP 6 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT THROUGH SUNDAY. EARLY NEXT WEEK A LOW PRESSURE SYSTEM
WILL ENCROACH ON THE DESERT SOUTHWEST RESULTING IN INCREASING
CLOUDS...COOLER TEMPERATURES...AND INCREASED CHANCES FOR MOUNTAIN
THUNDERSTORMS MAINLY ACROSS ARIZONA. THE LOW PRESSURE SYSTEM WILL
REMAIN A CONSTANT WEATHER FEATURE THROUGH THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
LATEST LOCAL SOUNDINGS DEPICT A WARM/DRY/STABLE ENVIRONMENT. NAM-WRF
APPEARS TO HAVE MOST ACCURATELY INITIALIZED THE TEMPS/MOISTURE
ACROSS THE REGION THIS MORNING. FORECAST FOR ABOVE NORMAL
TEMPERATURES AND NO PRECIP STILL HOLDS. NO CHANGES ARE ANTICIPATED
TO THE DATABASE THIS MORNING.
PREVIOUS DISCUSSION...
PLENTY OF SOLAR INSOLATION AND A DRY BOUNDARY LAYER WILL RESULT IN
WARMER TEMPERATURES TODAY ACROSS OUR CWA. LOCAL HEAT CRITERIA WILL
BE MET ACROSS SE CA/SW AZ WHICH PROMPTED THE ISSUANCE OF AN
EXCESSIVE HEAT WARNING. S-CNTRL AZ WILL BE JUST A BIT BELOW
CRITERIA...BUT IT/LL STILL BE A WARM ONE. ONE SAVING GRACE FROM THIS
BRIEF HEAT EPISODE IS THAT THE DRY AIR AND SHORTENING DAYS WILL MEAN
TEMPERATURES WILL COOL MORE QUICKLY THAN WOULD BE EXPECTED OF A JULY
OR AUGUST HEAT WAVE.
A LOW PRESSURE SYSTEM OFF THE SRN CA COAST WILL BEGIN TO ADVECT
MID-LEVEL MOISTURE INTO OUR CWA SUNDAY. BOUNDARY LAYER WILL STILL BE
VERY WARM WITH THERMALS RISING TO NEAR 600MB. THIS WILL AID
CONVECTIVE DEVELOPMENT OVER THE ERN AZ MOUNTAINS AND HAVE BROUGHT
SOME LOW END POPS FOR THAT AREA SUNDAY AFTERNOON. INCREASING CLOUDS
WILL ALSO TAPER TEMPERATURES JUST SLIGHTLY FROM TODAY/S VALUES WHICH
SHOULD KEEP US BELOW LOCAL HEAT WARNING CRITERIA.
MONDAY AND TUESDAY THE LOW WILL CONTINUE TO PULL ADDITIONAL MOISTURE
INTO MAINLY EASTERN ARIZONA WITH A PRONOUNCED DRY SLOT EXPECTED OVER
OUR WRN CWA. POPS REFLECT THIS SCENARIO WITH VALUES ELEVATED ACROSS
OUR FAR ERN CWA WITH LITTLE TO NO POPS ACROSS THE WRN CWA.
TEMPERATURES WILL CONTINUE TO COOL.
WEDNESDAY THROUGH FRIDAY...MODELS ARE BEING A BIT MORE AGGRESSIVE
WITH THE SHORTWAVE ENERGY OVER SRN CA...DEVELOPING A CUT-OFF LOW
THAT RETROGRADES OUT INTO THE OCEAN. MEANWHILE NW FLOW CONTINUES
ACROSS AZ. THIS H5 PATTERN WILL KEEP SOME LOW END /BELOW
CLIMATOLOGY/ POPS GOING OVER OUR ERN MOUNTAINS. TEMPERATURES WILL
FALL TO NEAR NORMAL LEVELS FOR THE TAIL-END OF THE FORECAST.
&&
.AVIATION...
MOSTLY CLEAR SKIES THROUGH THE AFTERNOON HOURS BEFORE FEW-SCT
MID-LEVEL CLOUDS DEVELOP OVER THE FORECAST AREA. EXPECT LIGHT
SURFACE WINDS AGAIN FOLLOWING A SIMILAR PATTERN AS FRIDAY. NO
AVIATION WEATHER CONCERNS EXPECTED THROUGH SUNDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES CAN BE EXPECTED
MONDAY...BEFORE A GRADUAL COOLING TREND WILL BRING TEMPERATURES TO
NEAR SEASONAL NORMALS BY WEDNESDAY. THE ATMOSPHERE WILL REMAIN
RELATIVELY DRY...WITH AFTERNOON RH VALUES IN THE TEENS MONDAY AND
TUESDAY...RISING A BIT BY WEDNESDAY INTO THE UPPER TEENS AND LOWER
TWENTIES ACROSS THE LOWER DESERTS. WINDS WILL GENERALLY BE LIGHT
WITH ONLY A FEW AFTERNOON GUSTS. A WEAK LOW PRESSURE SYSTEM WILL
DEVELOP OFF THE COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT
CHANCE OF THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM MST THIS
EVENING FOR AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM PDT THIS
EVENING FOR CAZ031>033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH/INIGUEZ
AVIATION...ROGERS
FIRE WEATHER...ROGERS
000
FXUS65 KPSR 061139
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
440 AM MST SAT SEP 6 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSION.
&&
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT THROUGH SUNDAY. EARLY NEXT WEEK A LOW PRESSURE SYSTEM
WILL ENCROACH ON THE DESERT SOUTHWEST RESULTING IN INCREASING
CLOUDS...COOLER TEMPERATURES...AND INCREASED CHANCES FOR MOUNTAIN
THUNDERSTORMS MAINLY ACROSS ARIZONA. THE LOW PRESSURE SYSTEM WILL
REMAIN A CONSTANT WEATHER FEATURE THROUGH THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
PLENTY OF SOLAR INSOLATION AND A DRY BOUNDARY LAYER WILL RESULT IN
WARMER TEMPERATURES TODAY ACROSS OUR CWA. LOCAL HEAT CRITERIA WILL
BE MET ACROSS SE CA/SW AZ WHICH PROMPTED THE ISSUANCE OF AN
EXCESSIVE HEAT WARNING. S-CNTRL AZ WILL BE JUST A BIT BELOW
CRITERIA...BUT IT/LL STILL BE A WARM ONE. ONE SAVING GRACE FROM THIS
BRIEF HEAT EPISODE IS THAT THE DRY AIR AND SHORTENING DAYS WILL MEAN
TEMPERATURES WILL COOL MORE QUICKLY THAN WOULD BE EXPECTED OF A JULY
OR AUGUST HEAT WAVE.
A LOW PRESSURE SYSTEM OFF THE SRN CA COAST WILL BEGIN TO ADVECT
MID-LEVEL MOISTURE INTO OUR CWA SUNDAY. BOUNDARY LAYER WILL STILL BE
VERY WARM WITH THERMALS RISING TO NEAR 600MB. THIS WILL AID
CONVECTIVE DEVELOPMENT OVER THE ERN AZ MOUNTAINS AND HAVE BROUGHT
SOME LOW END POPS FOR THAT AREA SUNDAY AFTERNOON. INCREASING CLOUDS
WILL ALSO TAPER TEMPERATURES JUST SLIGHTLY FROM TODAY/S VALUES WHICH
SHOULD KEEP US BELOW LOCAL HEAT WARNING CRITERIA.
MONDAY AND TUESDAY THE LOW WILL CONTINUE TO PULL ADDITIONAL MOISTURE
INTO MAINLY EASTERN ARIZONA WITH A PRONOUNCED DRY SLOT EXPECTED OVER
OUR WRN CWA. POPS REFLECT THIS SCENARIO WITH VALUES ELEVATED ACROSS
OUR FAR ERN CWA WITH LITTLE TO NO POPS ACROSS THE WRN CWA.
TEMPERATURES WILL CONTINUE TO COOL.
WEDNESDAY THROUGH FRIDAY...MODELS ARE BEING A BIT MORE AGGRESSIVE
WITH THE SHORTWAVE ENERGY OVER SRN CA...DEVELOPING A CUT-OFF LOW
THAT RETROGRADES OUT INTO THE OCEAN. MEANWHILE NW FLOW CONTINUES
ACROSS AZ. THIS H5 PATTERN WILL KEEP SOME LOW END /BELOW
CLIMATOLOGY/ POPS GOING OVER OUR ERN MOUNTAINS. TEMPERATURES WILL
FALL TO NEAR NORMAL LEVELS FOR THE TAIL-END OF THE FORECAST.
&&
.AVIATION...
MOSTLY CLEAR SKIES THROUGH THE AFTERNOON HOURS BEFORE FEW-SCT
MID-LEVEL CLOUDS DEVELOP OVER THE FORECAST AREA. EXPECT LIGHT
SURFACE WINDS AGAIN FOLLOWING A SIMILAR PATTERN AS FRIDAY. NO
AVIATION WEATHER CONCERNS EXPECTED THROUGH SUNDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES CAN BE EXPECTED
MONDAY...BEFORE A GRADUAL COOLING TREND WILL BRING TEMPERATURES TO
NEAR SEASONAL NORMALS BY WEDNESDAY. THE ATMOSPHERE WILL REMAIN
RELATIVELY DRY...WITH AFTERNOON RH VALUES IN THE TEENS MONDAY AND
TUESDAY...RISING A BIT BY WEDNESDAY INTO THE UPPER TEENS AND LOWER
TWENTIES ACROSS THE LOWER DESERTS. WINDS WILL GENERALLY BE LIGHT
WITH ONLY A FEW AFTERNOON GUSTS. A WEAK LOW PRESSURE SYSTEM WILL
DEVELOP OFF THE COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT
CHANCE OF THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM MST THIS
EVENING FOR AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM PDT THIS
EVENING FOR CAZ031>033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...INIGUEZ
AVIATION...ROGERS
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 060942
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
242 AM MST SAT SEP 6 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...CLEAR CONDITIONS PREVAIL ACROSS ARIZONA THIS MORNING.
A WEAK RIDGE OF HIGH PRESSURE IS CENTERED OFF THE WEST COAST OF
NORTHERN BAJA. A BROAD TROUGH OF LOW PRESSURE IS CENTERED OVER THE
NORTHERN GREAT PLAINS. THIS PUTS ARIZONA UNDER A RELATIVELY DRY
NORTHWEST FLOW ALOFT. THIS PATTERN WILL REMAIN OVER THE STATE
THROUGH TODAY. THIS PATTERN WILL BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH OVER THE THE NORTHERN GREAT PLAINS MOVES EAST AND A WEAK
TROUGH OF LOW PRESSURE LINGERS OFF THE WEST COAST. A STRONGER HIGH
PRESSURE CENTER IS EXPECTED TO BUILD OVER THE WESTERN GULF OF MEXICO
INTO NORTHERN MEXICO. THE AIR FLOW OVER ARIZONA WILL TURN MORE
SOUTHERLY...DRAWING UP MOISTURE AND INCREASING THE CHANCE OF SHOWERS
AND THUNDERSTORMS SUNDAY THROUGH MIDWEEK. THE CHANCE OF
PRECIPITATION ON SUNDAY WILL STILL BE LOW...WITH THE BEST CHANCE
OVER THE WHITE MTNS AND EASTERN MOGOLLON RIM WITH SOME HIGH-BASED
ACTIVITY. MOISTURE IS EXPECTED TO MOVE NORTH AND WEST ON MONDAY AND
TUESDAY...INCREASING THE CHANCE FOR PRECIPITATION ACROSS MUCH OF
NORTHERN ARIZONA.
FOR WEDNESDAY THROUGH FRIDAY...FORECAST MODELS MOVE A TROUGH THROUGH
THE CENTRAL AND NORTHERN ROCKIES INTO THE MIDWEST WITH SOME OF THE
SHORTWAVE ENERGY FORECAST TO CUT OFF TO OUR WEST. AT THE SAME
TIME...THE NORTHERN MEXICO RIDGE SHIFTS WEST. THIS PATTERN WILL
RESULT IN MAINLY SOUTHWEST FLOW FOR NORTHERN ARIZONA...CONTINUING TO
FILTER IN ENOUGH MOISTURE FOR AT LEAST A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS EACH DAY. TEMPERATURES ARE EXPECTED TO BE NEAR
SEASONAL NORMALS.
&&
.AVIATION...FOR THE 12Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
MONDAY THROUGH WEDNESDAY...THERE WILL BE SLIGHT CHANCES OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN OF
NORTHERN ARIZONA THROUGH THE PERIOD WITH THE GREATEST CHANCES OF
THUNDERSTORMS ALONG THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JVC
AVIATION/FIRE WX.....MAS
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KPSR 060930
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
230 AM MST SAT SEP 6 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT THROUGH SUNDAY. EARLY NEXT WEEK A LOW PRESSURE SYSTEM
WILL ENCROACH ON THE DESERT SOUTHWEST RESULTING IN INCREASING
CLOUDS...COOLER TEMPERATURES...AND INCREASED CHANCES FOR MOUNTAIN
THUNDERSTORMS MAINLY ACROSS ARIZONA. THE LOW PRESSURE SYSTEM WILL
REMAIN A CONSTANT WEATHER FEATURE THROUGH THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
PLENTY OF SOLAR INSOLATION AND A DRY BOUNDARY LAYER WILL RESULT IN
WARMER TEMPERATURES TODAY ACROSS OUR CWA. LOCAL HEAT CRITERIA WILL
BE MET ACROSS SE CA/SW AZ WHICH PROMPTED THE ISSUANCE OF AN
EXCESSIVE HEAT WARNING. S-CNTRL AZ WILL BE JUST A BIT BELOW
CRITERIA...BUT IT/LL STILL BE A WARM ONE. ONE SAVING GRACE FROM THIS
BRIEF HEAT EPISODE IS THAT THE DRY AIR AND SHORTENING DAYS WILL MEAN
TEMPERATURES WILL COOL MORE QUICKLY THAN WOULD BE EXPECTED OF A JULY
OR AUGUST HEAT WAVE.
A LOW PRESSURE SYSTEM OFF THE SRN CA COAST WILL BEGIN TO ADVECT
MID-LEVEL MOISTURE INTO OUR CWA SUNDAY. BOUNDARY LAYER WILL STILL BE
VERY WARM WITH THERMALS RISING TO NEAR 600MB. THIS WILL AID
CONVECTIVE DEVELOPMENT OVER THE ERN AZ MOUNTAINS AND HAVE BROUGHT
SOME LOW END POPS FOR THAT AREA SUNDAY AFTERNOON. INCREASING CLOUDS
WILL ALSO TAPER TEMPERATURES JUST SLIGHTLY FROM TODAY/S VALUES WHICH
SHOULD KEEP US BELOW LOCAL HEAT WARNING CRITERIA.
MONDAY AND TUESDAY THE LOW WILL CONTINUE TO PULL ADDITIONAL MOISTURE
INTO MAINLY EASTERN ARIZONA WITH A PRONOUNCED DRY SLOT EXPECTED OVER
OUR WRN CWA. POPS REFLECT THIS SCENARIO WITH VALUES ELEVATED ACROSS
OUR FAR ERN CWA WITH LITTLE TO NO POPS ACROSS THE WRN CWA.
TEMPERATURES WILL CONTINUE TO COOL.
WEDNESDAY THROUGH FRIDAY...MODELS ARE BEING A BIT MORE AGGRESSIVE
WITH THE SHORTWAVE ENERGY OVER SRN CA...DEVELOPING A CUT-OFF LOW
THAT RETROGRADES OUT INTO THE OCEAN. MEANWHILE NW FLOW CONTINUES
ACROSS AZ. THIS H5 PATTERN WILL KEEP SOME LOW END /BELOW
CLIMATOLOGY/ POPS GOING OVER OUR ERN MOUNTAINS. TEMPERATURES WILL
FALL TO NEAR NORMAL LEVELS FOR THE TAIL-END OF THE FORECAST.
&&
.AVIATION...
CLEAR SKIES THROUGH ABOUT 18Z SATURDAY BEFORE SOME HIGH BASED
CUMULUS...ABOVE 12 KFT ASL...DEVELOP OVER SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA. EXPECT LIGHT SURFACE WINDS AGAIN FOLLOWING A
SIMILAR PATTERN AS FRIDAY...THOUGH MORE DISTINCT WESTERLY DIRECTIONS
IN THE AFTERNOON FOR THE PHOENIX AREA THAN WAS OBSERVED FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY...BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM MST THIS
EVENING FOR AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM PDT THIS
EVENING FOR CAZ031>033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...INIGUEZ
AVIATION...AJ
FIRE WEATHER...ROGERS
000
FXUS65 KTWC 060852 CCA
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
152 AM MST SAT SEP 6 2008
.SYNOPSIS...MUCH DRIER AIR HAS ARRIVED IN SOUTHEAST ARIZONA
PROVIDING A SUNNY AND HOT DAY SATURDAY WITH ONLY ISOLATED
THUNDERSTORMS POSSIBLE NEAR THE INTERNATIONAL BORDER. MOISTURE
GRADUALLY BEGINS A RETURN ON SUNDAY AND CONTINUES THROUGH NEXT WEEK
WITH ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
EXPECTED.
&&
.DISCUSSION...MUCH DRIER AIR HAS ARRIVED IN SOUTHEAST ARIZONA...AS
IS CLEARLY DEPICTED ON THE 00Z KTWC SOUNDING WITH A PRECIPITABLE
WATER OF ONLY 0.44 INCH...THE DRIEST WE HAVE SEEN IN A LONG TIME. IR
SATELLITE SHOWS THE RESULT WITH CRYSTAL CLEAR SKIES ACROSS NOT ONLY
ARIZONA BUT MOST OF THE DESERT SOUTHWEST EARLY THIS MORNING. WITH
THE LACK OF MOISTURE SATURDAY PROMISES TO BE THE HOTTEST DAY OF THIS
WEEK WITH HIGHS NEAR 102 IN TUCSON...5-6 DEGREES ABOVE NORMAL FOR
EARLY SEPTEMBER. SATURDAY WILL BE DRY FOR MOST EVERYBODY...BUT WE
DID ADD SOME VERY LOW POPS NEAR THE INTERNATIONAL BORDER AS
SUGGESTED BY THE 06Z SREF/NAM POP FIELDS. MAYBE A LONE SHOWER NEAR
DOUGLAS OR NOGALES...MOST IF NOT ALL ACTIVITY WILL REMAIN IN SONORA.
MOISTURE BEGINS A GRADUAL RETURN TO SOUTHEAST ARIZONA SUNDAY...WITH
SLIGHTLY HIGHER DEWPOINTS...INSTABILITY...AND AT LEAST SMALL AMOUNTS
OF CAPE. SHOULD SEE MORE ISOLATED SHOWERS AND THUNDERSTORMS SUNDAY
AFTERNOON AND EVENING...ESPECIALLY ON THE HIGHER TERRAIN EAST OF
TUCSON. THE ADDITIONAL MOISTURE SHOULD KNOCK HIGH TEMPERATURES BACK
TO THE UPPER 90S SUNDAY AFTERNOON.
THEREAFTER...GENERAL TROUGHINESS TO THE WEST OF ARIZONA SHOULD
ENCOURAGE SOUTHERLY FLOW AND PULL WHATEVER MOISTURE IS LEFT IN
MEXICO NORTHBOUND TOWARD ARIZONA. INHERITED SLIGHT CHANCE POPS LOOK
FINE...FROM TUCSON METRO EAST...FOR MOST OF NEXT WEEK. JUST ENOUGH
MOISTURE TO KEEP A VERY LOW GRADE MONSOON LIMPING ALONG. PERHAPS THE
MOST INTERESTING POTENTIAL IN OUR FORECAST COMES FROM AN UNLIKELY
SOURCE...HURRICANE IKE CURRENTLY APPROACHING THE BAHAMAS. NEW 00Z
ECMWF DRIVES IKE DUE WEST ACROSS THE GULF OF MEXICO WITH NO
RECURVATURE AND CENTERS ITS REMNANTS IN CHIHUAHUA BY MONDAY
SEPTEMBER 15TH. OBVIOUSLY...HARD TO SAY MUCH WITH CONFIDENCE 10 DAYS
OUT. TIME WILL TELL.
&&
.AVIATION...CLEAR SKIES EXPECTED 12Z SATURDAY...WITH JUST A FEW
CUMULUS CLOUDS OVER THE HIGHER TERRAIN AFTER 18Z. MOST LOCATIONS
DRY...WITH VERY SLIGHT CHANCES OF AN ISOLATED THUNDERSTORM NEAR THE
KOLS AND KDUG TAF SITES SATURDAY AFTERNOON. ISOLATED STORM CHANCES
RETURN TO ALL TAF SITES ON SUNDAY. LIGHT DIURNALLY DRIVEN WINDS AT
5-15 KTS THROUGH SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
TURNER
WEATHER.GOV/TUCSON
000
FXUS65 KTWC 060846
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
145 AM MST SAT SEP 6 2008
.SYNOPSIS...MUCH DRIER AIR HAS ARRIVED IN SOUTHEAST ARIZONA
PROVIDING A SUNNY AND HOT DAY SATURDAY WITH ONLY ISOLATED
THUNDERSTORMS POSSIBLE NEAR THE INTERNATIONAL BORDER. MOISTURE
GRADUALLY BEGINS A RETURN ON SUNDAY AND CONTINUES THROUGH NEXT WEEK
WITH ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
EXPECTED.
&&
.DISCUSSION...MUCH DRIER AIR HAS ARRIVED IN SOUTHEAST ARIZONA...AS
IS CLEARLY DEPICTED ON THE 00Z KTWC SOUNDING WITH A PRECIPITABLE
WATER OF ONLY 0.44 INCH...THE DRIEST WE HAVE SEEN IN A LONG TIME. IR
SATELLITE SHOWS THE RESULT WITH CRYSTAL CLEAR SKIES ACROSS NOT ONLY
ARIZONA BUT MOST OF THE DESERT SOUTHWEST EARLY THIS MORNING. WITH
THE LACK OF MOISTURE SATURDAY PROMISES TO BE THE HOTTEST DAY OF THIS
WEEK WITH HIGHS NEAR 102 IN TUCSON...5-6 DEGREES ABOVE NORMAL FOR
EARLY SEPTEMBER. SATURDAY WILL BE DRY FOR MOST EVERYBODY...BUT WE
DID ADD SOME VERY LOW POPS NEAR THE INTERNATIONAL BORDER AS
SUGGESTED BY THE 06Z SREF/NAM POP FIELDS. MAYBE A LONE SHOWER NEAR
DOUGLAS OR NOGALES...MOST IF NOT ALL ACTIVITY WILL REMAIN IN SONORA.
MOISTURE BEGINS A GRADUAL RETURN TO SOUTHEAST ARIZONA SUNDAY...WITH
SLIGHTLY HIGHER DEWPOINTS...INSTABILITY...AND AT LEAST SMALL AMOUNTS
OF CAPE. SHOULD SEE MORE ISOLATED SHOWERS AND THUNDERSTORMS SUNDAY
AFTERNOON AND EVENING...ESPECIALLY ON THE HIGHER TERRAIN EAST OF
TUCSON. THE ADDITIONAL MOISTURE SHOULD KNOCK HIGH TEMPERATURES BACK
TO THE UPPER 90S SUNDAY AFTERNOON.
THEREAFTER...GENERAL TROUGHINESS TO THE WEST OF ARIZONA SHOULD
ENCOURAGE SOUTHERLY FLOW AND PULL WHATEVER MOISTURE IS LEFT IN
MEXICO NORTHBOUND TOWARD ARIZONA. INHERITED SLIGHT CHANCE POPS LOOK
FINE...FROM TUCSON METRO EAST...FOR MOST OF NEXT WEEK. JUST ENOUGH
MOISTURE TO KEEP A VERY LOW GRADE MONSOON LIMPING ALONG. PERHAPS THE
MOST INTERESTING POTENTIAL IN OUR FORECAST COMES FROM AN UNLIKELY
SOURCE...HURRICANE IKE CURRENTLY APPROACHING THE BAHAMAS. NEW 12Z
ECMWF DRIVES IKE DUE WEST ACROSS THE GULF OF MEXICO WITH NO
RECURVATURE AND CENTERS ITS REMNANTS IN CHIHUAHUA BY MONDAY
SEPTEMBER 15TH. OBVIOUSLY...HARD TO SAY MUCH WITH CONFIDENCE 10 DAYS
OUT. TIME WILL TELL.
&&
.AVIATION...CLEAR SKIES EXPECTED 12Z SATURDAY...WITH JUST A FEW
CUMULUS CLOUDS OVER THE HIGHER TERRAIN AFTER 18Z. MOST LOCATIONS
DRY...WITH VERY SLIGHT CHANCES OF AN ISOLATED THUNDERSTORM NEAR THE
KOLS AND KDUG TAF SITES SATURDAY AFTERNOON. ISOLATED STORM CHANCES
RETURN TO ALL TAF SITES ON SUNDAY. LIGHT DIURNALLY DRIVEN WINDS AT
5-15 KTS THROUGH SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
TURNER
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 060508
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1005 PM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT OVER THE WEEKEND. SOME RECORD HIGH TEMPERATURES ARE
POSSIBLE ACROSS SOUTHEAST CALIFORNIA INTO PARTS OF SOUTH-CENTRAL
ARIZONA. EARLY NEXT WEEK...LOW PRESSURE WILL DEVELOP NEAR THE WEST
COAST...HELPING TO PULL SOME MEXICAN MOISTURE BACK INTO THE AREA.
THIS WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVER THE SOUTH-CENTRAL HIGHER TERRAIN BEGINNING MONDAY. THE UPPER
LOW WILL ALSO PRODUCE A LOWERING OF AFTERNOON TEMPERATURES.
&&
.DISCUSSION...
LARGE SCALE FLOW PATTERN HAS A RIDGE OVER THE NORTHEAST PACIFIC AND
TROUGHING CENTERED OVER THE PLAINS. THE RIDGE IS SOMETHING OF A REX
PATTERN WITH UNDERCUTTING FLOW. THERE APPEAR TO BE SOMEWHAT
STATIONARY CYCLONIC CIRCULATIONS EMBEDDED WITHIN THAT FLOW ALONG AT
ABOUT 30N LATITUDE. TO THE SOUTH OF THAT IS AN ANTICYCLONE WITH
SOMETHING OF A JET STREAK IN BETWEEN. OVER FAR NORTHERN BAJA AND FAR
SOUTHERN CALIFORNIA THERE APPEARS TO BE A DEFORMATION ZONE WHICH
AIDED STORM DEVELOPMENT OVER THE BAJA MOUNTAINS VERY CLOSE TO THE
INTERNATIONAL BORDER. 00Z PLOTS SHOW THE 500 MB RIDGE EXTENDING
SOUTHEASTWARD INTO ARIZONA. THE INFLUENCE OF THE RIDGE ALONG WITH
DRIER AIR HAS ALLOWED TEMPERATURES TO CLIMB THE PAST FEW DAYS.
SLIGHTLY WARMER TEMPERATURES ARE FORECAST FOR TOMORROW AND THIS WILL
PUT SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA JUST INTO EXCESSIVE
HEAT WARNING CRITERIA. CURRENT FORECASTS ARE FOR SLIGHTLY COOLER
TEMPERATURES SUNDAY AS THE ANTICYCLONIC FLOW ALOFT EXTENDS A BIT
FURTHER EASTWARD AND LOWER LEVELS MOISTEN A LITTLE BIT...MAINLY IN
SOUTHWEST ARIZONA. THIS IS SUPPORTED BY LATEST PROGS.
OTHERWISE...THINGS LOOK TO BE TOO DRY TO GET ANY STORMS GOING OVER
THE LOWER DESERTS SATURDAY AS THE UPPER LEVEL SPEED MAX MOVES ACROSS
THE AREA. OTHERWISE THINGS LOOK GOOD.
PREVIOUS DISCUSSION...
UPDATED SECTION POSTED AT 558 PM MST/PDT: ISSUED EXCESSIVE HEAT
WARNING FOR LOWER DESERT OF FAR SOUTHEAST CALIFORNIA AND
WEST-CENTRAL AZ FOR SATURDAY. FORECAST DAYTIME HIGHS SATURDAY ARE
EXPECTED TO BE 1 TO 2 DEGREES ABOVE WHAT OCCURRED TODAY AT MOST CWA
LOCALES...AND IT WAS HOT OUT THAT WAY TODAY...WITH 112 AT
PARKER...111 AT IMPERIAL...AND 110 AT BLYTHE. ADJUSTED CORRESPONDING
TEMP/RH/HEAT INDEX GRIDS TO REFLECT SLIGHTLY WARMER MAX TEMP
EXPECTATION FOR SATURDAY...ESPECIALLY IN THE YUMA AREA...WHERE RAWS
SITES REPORTED MAX TEMPS ABOVE 110 TODAY.
NOTE TO OUR CUSTOMERS: TEMPERATURES PROVIDED FROM YUMA ASOS SITE
APPEAR SUSPECT/UNRELIABLE. FOR EXAMPLE...THE MAX TEMP RECORDED AT
THE YUMA ASOS SITE TODAY WAS ONLY 105...WHILE NEARBY RAWS SITES
REPORTED MAX TEMPS AROUND 112. AROUND 4 PM...A PNS WAS POSTED
CONCERNING THIS MATTER (PLEASE REFER TO PHXPNSPSR (NOUS45) ISSUED AT
2302 UTC FOR FURTHER DETAILS).
A FEW FLAT CUMULUS CLOUDS WERE NOTED DRIFTING ACROSS THE
AFTERNOON SKIES ON REGIONAL SATELLITE PIX. MEANWHILE...FURTHER TO
THE SW...SUFFICIENT MOISTURE REMAINED ALONG THE BAJA SPINE FOR YET
ANOTHER BATCH OF TSTMS. SERIOUSLY DOUBT ANY OF THIS CONVECTION WILL
DEVELOP/ MOVE INTO IMPERIAL COUNTY...AS THEY SHOULD PRETTY REMAIN
MOUNTAIN-HUGGERS. POTENTIAL OUTFLOWS OR VERY ISOLD DEVELOPMENT OVER
ANY OF IMPERIAL COUNTY COULD ADEQUATELY BE COVERED BY NOWCASTS.
NOT EXPECTING MUCH CHANGE WITH REGARDS TO THE LONGWAVE H5 PATTERN
OVER OUR AREA FOR THE WEEKEND...WITH BROAD UPPER TROUGH OVER NRN
STATE TO CONTINUE...KEEPING THE UPPER RIDGE FROM TREKKING NWD AND
LEAVING US IN A DRY NWLY FLOW. HOWEVER...SOME CHANGES ANTICIPATED
EARLY NEXT WEEK AS A WEAK BAGGY TROUGH DEVELOPS ALONG THE WEST
COAST. MODELS IMPLY THIS TROUGH WILL PULL UP LIMITED AMOUNTS OF
MOISTURE FROM MEXICO OVER ERN AZ EARLY NEXT WEEK...SO SLIGHT CHANCE
OF TSTMS ZONE 24 MONDAY AND THEREAFTER STILL APPEARS ON TRACK. LATER
SHIFTS WILL NEED TO WATCH OUT FOR THE POSSIBILITY OF MOISTURE
ADVECTING FURTHER TO THE N AND W BY TUESDAY/WEDNESDAY TIME FRAME.
FOR NOW...WILL KEEP SLIGHT CHANCES CONFINED TO ZONE 24...BUT CALL
FOR MORE CLOUDINESS IN SKY GRIDS CWA-WIDE. IN ADDITION...DUE TO
LOWERING HEIGHTS AND THICKNESSES...WILL LOWER TEMPS DOWN CLOSER TO
SEASONAL NORMALS BY MIDDLE OF NEXT WEEK.
&&
.AVIATION...
CLEAR SKIES THROUGH ABOUT 18Z SATURDAY BEFORE SOME HIGH BASED
CUMULUS...ABOVE 12 KFT ASL...DEVELOP OVER SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA. EXPECT LIGHT SURFACE WINDS AGAIN FOLLOWING A
SIMILAR PATTERN AS FRIDAY...THOUGH MORE DISTINCT WESTERLY DIRECTIONS
IN THE AFTERNOON FOR THE PHOENIX AREA THAN WAS OBSERVED FRIDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY...BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 10 AM MST TO 8 PM MST SATURDAY FOR
AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM PDT TO 8 PM PDT SATURDAY FOR
CAZ031-032-033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...AJ/DG/ESTLE
AVIATION...AJ
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 060300
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
800 PM MST FRI SEP 5 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...SKIES HAVE CLEARED THIS EVENING ACROSS ALL OF NORTHERN
ARIZONA. WITH A DRY AIRMASS STILL IN PLACE...EXPECT ANOTHER COOL
NIGHT WITH LOW TEMPERATURES RUNNING A DEGREE OR TWO BELOW NORMAL.
SOME OF THE COOLER LOCATIONS WILL SEE LOWS DIP INTO THE MID 30S
AGAIN BY THE EARLY MORNING HOURS. THE CURRENT FORECAST IS IN GOOD
SHAPE AND NO UPDATES ARE PLANNED THIS EVENING.
PREV DISCUSSION (300 PM MST)...A HIGH PRESSURE RIDGE WILL REMAIN
OVER THE STATE THROUGH SATURDAY. THIS WILL RESULT IN DRY WEATHER
WITH MAINLY CLEAR SKIES...WARM AFTERNOONS AND COOL NIGHTS.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH RESPONSIBLE FOR THE NORTHWEST FLOW OVER ARIZONA MOVES EAST
AND A WEAK TROUGH OF LOW PRESSURE LINGERS OFF THE WEST COAST. A
HIGH PRESSURE CENTER IS ALSO EXPECTED TO BUILD OVER THE WESTERN GULF
OF MEXICO INTO NORTHERN MEXICO. THE AIR FLOW OVER ARIZONA SHOULD
TURN MORE SOUTHERLY...DRAWING UP MOISTURE AND INCREASING THE CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. STORM CHANCES FOR
SUNDAY LOOK SLIM BASED ON FORECAST SOUNDINGS...MAINLY AFFECTING THE
WHITE MTNS AND EASTERN MOGOLLON RIM WITH SOME HIGH-BASED ACTIVITY.
FOR MONDAY AND TUESDAY...LOW LEVEL MOISTURE SHOULD INCREASE...
BRINGING A BETTER CHANCE OF SHOWERS AND STORMS.
FOR WEDNESDAY THROUGH FRIDAY...FORECAST MODELS MOVE A TROUGH THROUGH
THE CENTRAL AND NORTHERN ROCKIES INTO THE MIDWEST WITH SOME OF THE
SHORTWAVE ENERGY FORECAST TO CUT OFF TO OUR WEST. AT THE SAME
TIME...THE NORTHERN MEXICO RIDGE SHIFTS WEST. THIS PATTERN WILL
RESULT IN MAINLY SOUTHWEST FLOW FOR NORTHERN ARIZONA...CONTINUING TO
FILTER IN ENOUGH MOISTURE FOR AT LEAST A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS EACH DAY. TEMPERATURES ARE EXPECTED TO BE NEAR
SEASONAL NORMALS.
&&
.AVIATION...FOR THE 06Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
MONDAY THROUGH WEDNESDAY...THERE WILL BE SLIGHT CHANCES OF MAINLY
AFTERNOON AND EVENING THUNDERSTORMS...PRIMARILY OVER THE HIGHER
TERRAIN OF NORTHERN ARIZONA THROUGH THE PERIOD.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............DDV
AVIATION/FIRE WX.....DDV
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KTWC 060244
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
745 PM MST FRI SEP 5 2008
.SYNOPSIS...DRIER AIR OVER SOUTHEAST ARIZONA WILL RESULT IN MOSTLY
CLEAR SKIES THIS WEEKEND WITH HOTTER AFTERNOONS. MOISTURE WILL
SLOWLY AND GRADUALLY MOVE BACK INTO SOUTHEAST ARIZONA BEGINNING LATE
SUNDAY....RESULTING IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
NEXT WEEK.
&&
.DISCUSSION...CURRENT SATELLITE IMAGERY SHOWS CLEAR SKIES OVER MUCH
OF ARIZONA WITH A WIDE RANGE OF DEWPOINT VALUES. WHILE MOST STATIONS
HAVE DEWPOINT VALUES IN THE UPPER 30S TO MID 40S...KOLS SHOWS A
DEWPOINT IN THE MID 50S. 00Z KTWC SOUNDING SHOWS PW VALUES LESS THAN
A HALF AN INCH (0.41 IN) AND A FAIRLY STABLE ATMOSPHERE. ALL THESE
ITEMS SPELL OUT A CLEAR AND QUIET NIGHT FOR AT LEAST THE SOUTHEAST
PORTION OF THE STATE.
LOOKING OVER CURRENT MODEL DATA...SEE NO REASON TO CHANGE INHERITED
FORECAST. THAT SAID...FOR FORECAST DETAILS...PLEASE REFER TO THE
PREV DISCUSSION SECTION BELOW.
&&
.AVIATION...DRIER AIR OVER SOUTHEAST ARIZONA WILL RESULT IN MOSTLY
CLEAR SKIES INTO THIS WEEKEND WITH HOTTER AFTERNOONS. MOISTURE WILL
SLOWLY AND GRADUALLY MOVE BACK INTO SOUTHEAST ARIZONA BEGINNING
SUNDAY....RESULTING IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
NEXT WEEK. OTHERWISE... EXPECT LIGHT DIURNALLY DRIVEN SURFACE WINDS
TONIGHT AND SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.PREV DISCUSSION...A DRY AIRMASS IN PLACE WITH THIS MORNINGS KTWC
SOUNDING SHOWING A PWAT OF ONLY 0.77 INCHES. THIS IS DOWN 0.37
INCHES IN 24 HOURS. WITH THAT SAID...WE ARE DRY ENOUGH TO PRECLUDE
THE DEVELOPMENT OF ANY STORMS FOR THIS AFTERNOON AND EVENING...AND
THIS WILL CONTINUE THROUGH SATURDAY.
BY SUNDAY THE MODELS SHOW A LOW DEVELOPING ALONG THE CALIFORNIA
COAST WITH SOME POTENTIAL FOR MOISTURE TO INCREASE AS THE LOW TO MID
LEVEL FLOW TRIES TO BECOME MORE SOUTHERLY...AND A PIECE OF ENERGY
SWINGS THROUGH THE STATE AND TO OUR NORTHEAST BY TUESDAY.
BOTH THE GFS AND ECMWF SHOW ANOTHER TROUGH DROPPING SOUTH FROM THE
PAC NW/WESTERN CANADA. THIS SYSTEM IS PROGGED TO LIE ACROSS IDAHO...
NEVADA AND SOUTH CENTRAL CALIFORNIA BY LATE IN THE AFTERNOON ON
WEDNESDAY.
THE 12Z RUN OF THE ECMWF IS NOW MORE IN LINE WITH THE 12Z RUN OF THE
GFS...BUT STILL WITH SOME SIGNIFICANT DIFFERENCES. THE GFS SHOWS THE
MAIN MID TO UPPER LEVEL VORT MAX HEADING INTO THE MIDWEST BY LATE
THURSDAY...WHILE THE ECMWF SHOWS THE VORT MAX OVER SE WYOMING AND
INTO NE UTAH. BOTH MODELS CUTOFF A LOW OFFSHORE OF SOUTHERN
CALIFORNIA ON THURSDAY WITH A LARGE RIDGE OVER NE MEXICO AND SRN
TEXAS WHICH WILL RESULT IN SW FLOW ACROSS THE DESERT SOUTHWEST.
BY FRIDAY THE MODELS SHOW A SIMILAR SETUP WITH A RIDGE TO OUR SE AND
A LOW TO OUR WEST...BUT THE ECMWF HAS THE LOW OFF THE SRN CALIFORNIA
COAST ABOUT 300 MILES...BUT THE GFS HAS THE LOW ABOUT 800 MILES TO
THE WEST OF THE SRN CALIFORNIA COAST. IT IS LIKELY THAT SOME
MOISTURE INCREASE WILL LIKELY BEGIN LATE SUNDAY AND CONTINUE THROUGH
THE WEEK AS THE TROUGHINESS PERSISTS TO OUR WEST...BUT THERE ARE
ENOUGH DIFFERENCES TO JUST HOLD ON TO THE SLIGHT CHANCE POPS FOR
GENERALLY MONDAY THROUGH THURSDAY...MAINLY ALONG THE NEW MEXICO
BORDER.
HIGHS WILL BE 5 TO 7 DEGS ABOVE NORMAL FOR SATURDAY...AND 3 TO 5
DEGS ABOVE NORMAL FOR SUNDAY AND MONDAY. THEREAFTER...EXPECT HIGHS
TO HOVER NEAR NORMAL. LOWS WILL BE AT OR SLIGHTLY BELOW NORMAL FOR
TONIGHT/EARLY SATURDAY...THEN 2 TO 4 DEGS ABOVE NORMAL EACH MORNING
THROUGH NEXT FRIDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
MOLLERE
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 060100 AAA
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
600 PM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT OVER THE WEEKEND. SOME RECORD HIGH TEMPERATURES ARE
POSSIBLE ACROSS SOUTHEAST CALIFORNIA INTO PARTS OF SOUTH-CENTRAL
ARIZONA. EARLY NEXT WEEK...LOW PRESSURE WILL DEVELOP NEAR THE WEST
COAST...HELPING TO PULL SOME MEXICAN MOISTURE BACK INTO THE AREA.
THIS WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVER THE SOUTH-CENTRAL HIGHER TERRAIN BEGINNING MONDAY. THE UPPER
LOW WILL ALSO PRODUCE A LOWERING OF AFTERNOON TEMPERATURES.
&&
.DISCUSSION...
UPDATED SECTION POSTED AT 558 PM MST/PDT: ISSUED EXCESSIVE HEAT
WARNING FOR LOWER DESERT OF FAR SOUTHEAST CALIFORNIA AND
WEST-CENTRAL AZ FOR SATURDAY. FORECAST DAYTIME HIGHS SATURDAY ARE
EXPECTED TO BE 1 TO 2 DEGREES ABOVE WHAT OCCURRED TODAY AT MOST CWA
LOCALES...AND IT WAS HOT OUT THAT WAY TODAY...WITH 112 AT
PARKER...111 AT IMPERIAL...AND 110 AT BLYTHE. ADJUSTED CORRESPONDING
TEMP/RH/HEAT INDEX GRIDS TO REFLECT SLIGHTLY WARMER MAX TEMP
EXPECTATION FOR SATURDAY...ESPECIALLY IN THE YUMA AREA...WHERE RAWS
SITES REPORTED MAX TEMPS ABOVE 110 TODAY.
NOTE TO OUR CUSTOMERS: TEMPERATURES PROVIDED FROM YUMA ASOS SITE
APPEAR SUSPECT/UNRELIABLE. FOR EXAMPLE...THE MAX TEMP RECORDED AT
THE YUMA ASOS SITE TODAY WAS ONLY 105...WHILE NEARBY RAWS SITES
REPORTED MAX TEMPS AROUND 112. AROUND 4 PM...A PNS WAS POSTED
CONCERNING THIS MATTER (PLEASE REFER TO PHXPNSPSR (NOUS45) ISSUED AT
2302 UTC FOR FURTHER DETAILS).
AFTERNOON DISCUSSION FOLLOWS...A FEW FLAT CUMULUS CLOUDS WERE NOTED
DRIFTING ACROSS THE AFTERNOON SKIES ON REGIONAL SATELLITE PIX.
MEANWHILE...FURTHER TO THE SW...SUFFICIENT MOISTURE REMAINED ALONG
THE BAJA SPINE FOR YET ANOTHER BATCH OF TSTMS. SERIOUSLY DOUBT ANY
OF THIS CONVECTION WILL DEVELOP/ MOVE INTO IMPERIAL COUNTY...AS THEY
SHOULD PRETTY REMAIN MOUNTAIN-HUGGERS. POTENTIAL OUTFLOWS OR VERY
ISOLD DEVELOPMENT OVER ANY OF IMPERIAL COUNTY COULD ADEQUATELY BE
COVERED BY NOWCASTS.
NOT EXPECTING MUCH CHANGE WITH REGARDS TO THE LONGWAVE H5 PATTERN
OVER OUR AREA FOR THE WEEKEND...WITH BROAD UPPER TROUGH OVER NRN
STATE TO CONTINUE...KEEPING THE UPPER RIDGE FROM TREKKING NWD AND
LEAVING US IN A DRY NWLY FLOW. HOWEVER...SOME CHANGES ANTICIPATED
EARLY NEXT WEEK AS A WEAK BAGGY TROUGH DEVELOPS ALONG THE WEST
COAST. MODELS IMPLY THIS TROUGH WILL PULL UP LIMITED AMOUNTS OF
MOISTURE FROM MEXICO OVER ERN AZ EARLY NEXT WEEK...SO SLIGHT CHANCE
OF TSTMS ZONE 24 MONDAY AND THEREAFTER STILL APPEARS ON TRACK. LATER
SHIFTS WILL NEED TO WATCH OUT FOR THE POSSIBILITY OF MOISTURE
ADVECTING FURTHER TO THE N AND W BY TUESDAY/WEDNESDAY TIME FRAME.
FOR NOW...WILL KEEP SLIGHT CHANCES CONFINED TO ZONE 24...BUT CALL
FOR MORE CLOUDINESS IN SKY GRIDS CWA-WIDE. IN ADDITION...DUE TO
LOWERING HEIGHTS AND THICKNESSES...WILL LOWER TEMPS DOWN CLOSER TO
SEASONAL NORMALS BY MIDDLE OF NEXT WEEK.
&&
.AVIATION...
JUST ENOUGH MOISTURE IN THE LOWER LEVELS THIS AFTERNOON FOR SOME
BUILDUPS MAINLY OVER THE HIGHER TERRAIN. STILL EXPECTING THESE
CLOUDS TO DISSIPATE QUICKLY AFTER 0100Z...FOR CLEAR SKIES BLO 12
THSD FT. WINDS WILL REMAIN LIGHT. THUS NO AVIATION CONCERNS THRU
SATURDAY 18Z.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY...BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...EXCESSIVE HEAT WARNING FROM 10 AM MST TO 8 PM MST SATURDAY FOR
AZZ020-021-025-026.
CA...EXCESSIVE HEAT WARNING FROM 10 AM PDT TO 8 PM PDT SATURDAY FOR
CAZ031-032-033.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...ESTLE/INIGUEZ/DG
AVIATION...SIPPLE
FIRE WEATHER...ROGERS
000
FXUS65 KPSR 052228
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 PM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT OVER THE WEEKEND. SOME RECORD HIGH TEMPERATURES ARE
POSSIBLE ACROSS SOUTHEAST CALIFORNIA INTO PARTS OF SOUTH-CENTRAL
ARIZONA. EARLY NEXT WEEK...LOW PRESSURE WILL DEVELOP NEAR THE WEST
COAST...HELPING TO PULL SOME MEXICAN MOISTURE BACK INTO THE AREA.
THIS WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVER THE SOUTH-CENTRAL HIGHER TERRAIN BEGINNING MONDAY. THE UPPER
LOW WILL ALSO PRODUCE A LOWERING OF AFTERNOON TEMPERATURES.
&&
.DISCUSSION...
A FEW FLAT CUMULUS CLOUDS WERE NOTED DRIFTING ACROSS THE AFTERNOON
SKIES ON REGIONAL SATELLITE PIX. MEANWHILE...FURTHER TO THE SW...
SUFFICIENT MOISTURE REMAINED ALONG THE BAJA SPINE FOR YET ANOTHER
BATCH OF TSTMS. SERIOUSLY DOUBT ANY OF THIS CONVECTION WILL DEVELOP/
MOVE INTO IMPERIAL COUNTY...AS THEY SHOULD PRETTY REMAIN MOUNTAIN-
HUGGERS. POTENTIAL OUTFLOWS OR VERY ISOLD DEVELOPMENT OVER ANY OF
IMPERIAL COUNTY COULD ADEQUATELY BE COVERED BY NOWCASTS.
NOT EXPECTING MUCH CHANGE WITH REGARDS TO THE LONGWAVE H5 PATTERN
OVER OUR AREA FOR THE WEEKEND...WITH BROAD UPPER TROUGH OVER NRN
STATE TO CONTINUE...KEEPING THE UPPER RIDGE FROM TREKKING NWD AND
LEAVING US IN A DRY NWLY FLOW. HOWEVER...SOME CHANGES ANTICIPATED
EARLY NEXT WEEK AS A WEAK BAGGY TROUGH DEVELOPS ALONG THE WEST
COAST. MODELS IMPLY THIS TROUGH WILL PULL UP LIMITED AMOUNTS OF
MOISTURE FROM MEXICO OVER ERN AZ EARLY NEXT WEEK...SO SLIGHT CHANCE
OF TSTMS ZONE 24 MONDAY AND THEREAFTER STILL APPEARS ON TRACK. LATER
SHIFTS WILL NEED TO WATCH OUT FOR THE POSSIBILITY OF MOISTURE
ADVECTING FURTHER TO THE N AND W BY TUESDAY/WEDNESDAY TIME FRAME.
FOR NOW...WILL KEEP SLIGHT CHANCES CONFINED TO ZONE 24...BUT CALL
FOR MORE CLOUDINESS IN SKY GRIDS CWA-WIDE. IN ADDITION...DUE TO
LOWERING HEIGHTS AND THICKNESSES...WILL LOWER TEMPS DOWN CLOSER TO
SEASONAL NORMALS BY MIDDLE OF NEXT WEEK.
&&
.AVIATION...
JUST ENOUGH MOISTURE IN THE LOWER LEVELS THIS AFTERNOON FOR SOME
BUILDUPS MAINLY OVER THE HIGHER TERRAIN. STILL EXPECTING THESE
CLOUDS TO DISSIPATE QUICKLY AFTER 0100Z...FOR CLEAR SKIES BLO 12
THSD FT. WINDS WILL REMAIN LIGHT. THUS NO AVIATION CONCERNS THRU
SATURDAY 18Z.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY...BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...ESTLE/INIGUEZ
AVIATION...SIPPLE
FIRE WEATHER...ROGERS
000
FXUS65 KPSR 052227
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 PM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
A DRY NORTHWEST FLOW ALOFT WILL KEEP THE DESERT SOUTHWEST GENERALLY
CLEAR AND HOT OVER THE WEEKEND. SOME RECORD HIGH TEMPERATURES ARE
POSSIBLE ACROSS SOUTHEAST CALIFORNIA INTO PARTS OF SOUTH-CENTRAL
ARIZONA. EARLY NEXT WEEK...LOW PRESSURE WILL DEVELOP NEAR THE WEST
COAST...HELPING TO PULL SOME MEXICAN MOISTURE BACK INTO THE AREA.
THIS WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVER THE SOUTH-CENTRAL HIGHER TERRAIN BEGINNING MONDAY. THE UPPER
LOW WILL ALSO PRODUCE A LOWERING OF AFTERNOON TEMPERATURES.
&&
.DISCUSSION...
A FEW FLAT CUMULUS CLOUDS WERE NOTED DRIFTING ACROSS THE AFTERNOON
SKIES ON REGIONAL SATELLITE PIX. MEANWHILE...FURTHER TO THE SW...
SUFFICIENT MOISTURE REMAINED ALONG THE BAJA SPINE FOR YET ANOTHER
BATCH OF TSTMS. SERIOUSLY DOUBT ANY OF THIS CONVECTION WILL DEVELOP/
MOVE INTO IMPERIAL COUNTY...AS THEY SHOULD PRETTY REMAIN MOUNTAIN-
HUGGERS. POTENTIAL OUTFLOWS OR VERY ISOLD DEVELOPMENT OVER ANY OF
IMPERIAL COUNTY COULD ADEQUATELY BE COVERED BY NOWCASTS.
NOT EXPECTING MUCH CHANGE WITH REGARDS TO THE LONGWAVE H5 PATTERN
OVER OUR AREA FOR THE WEEKEND...WITH BROAD UPPER TROUGH OVER NRN
STATE TO CONTINUE...KEEPING THE UPPER RIDGE FROM TREKKING NWD AND
LEAVING US IN A DRY NWLY FLOW. HOWEVER...SOME CHANGES ANTICIPATED
EARLY NEXT WEEK AS A WEAK BAGGY TROUGH DEVELOPS ALONG THE WEST
COAST. MODELS IMPLY THIS TROUGH WILL PULL UP LIMITED AMOUNTS OF
MOISTURE FROM MEXICO OVER ERN AZ EARLY NEXT WEEK...SO SLIGHT CHANCE
OF TSTMS ZONE 24 MONDAY AND THEREAFTER STILL APPEARS ON TRACK. LATER
SHIFTS WILL NEED TO WATCH OUT FOR THE POSSIBILITY OF MOISTURE
ADVECTING FURTHER TO THE N AND W BY TUESDAY/WEDNESDAY TIME FRAME.
FOR NOW...WILL KEEP SLIGHT CHANCES CONFINED TO ZONE 24...BUT CALL
FOR MORE CLOUDINESS IN SKY GRIDS CWA-WIDE. IN ADDITION...DUE TO
LOWERING HEIGHTS AND THICKNESSES...WILL LOWER TEMPS DOWN CLOSER TO
SEASONAL NORMALS BY MIDDLE OF NEXT WEEK.
&&
.AVIATION...
JUST ENOUGH MOISTURE IN THE LOWER LEVELS THIS AFTERNOON FOR SOME
BUILDUPS MAINLY OVER THE HIGHER TERRAIN. STILL EXPECTING THESE
CLOUDS TO DISSIPATE QUICKLY AFTER 0100Z...FOR CLEAR SKIES BLO 12
THSD FT. WINDS WILL REMAIN LIGHT. THUS NO AVIATION CONCERNS THRU
SATURDAY 18Z.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY..BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...ESTLE/INIGUEZ
AVIATION...SIPPLE
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 052200
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
300 PM MST FRI SEP 5 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...A HIGH PRESSURE RIDGE WILL REMAIN OVER THE STATE
THROUGH SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH MAINLY CLEAR
SKIES...WARM AFTERNOONS AND COOL NIGHTS.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH RESPONSIBLE FOR THE NORTHWEST FLOW OVER ARIZONA MOVES EAST
AND A WEAK TROUGH OF LOW PRESSURE LINGERS OFF THE WEST COAST. A
HIGH PRESSURE CENTER IS ALSO EXPECTED TO BUILD OVER THE WESTERN GULF
OF MEXICO INTO NORTHERN MEXICO. THE AIR FLOW OVER ARIZONA SHOULD
TURN MORE SOUTHERLY...DRAWING UP MOISTURE AND INCREASING THE CHANCE
OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. STORM CHANCES FOR
SUNDAY LOOK SLIM BASED ON FORECAST SOUNDINGS...MAINLY AFFECTING THE
WHITE MTNS AND EASTERN MOGOLLON RIM WITH SOME HIGH-BASED ACTIVITY.
FOR MONDAY AND TUESDAY...LOW LEVEL MOISTURE SHOULD INCREASE...
BRINGING A BETTER CHANCE OF SHOWERS AND STORMS.
FOR WEDNESDAY THROUGH FRIDAY...FORECAST MODELS MOVE A TROUGH THROUGH
THE CENTRAL AND NORTHERN ROCKIES INTO THE MIDWEST WITH SOME OF THE
SHORTWAVE ENERGY FORECAST TO CUT OFF TO OUR WEST. AT THE SAME
TIME...THE NORTHERN MEXICO RIDGE SHIFTS WEST. THIS PATTERN WILL
RESULT IN MAINLY SOUTHWEST FLOW FOR NORTHERN ARIZONA...CONTINUING TO
FILTER IN ENOUGH MOISTURE FOR AT LEAST A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS EACH DAY. TEMPERATURES ARE EXPECTED TO BE NEAR
SEASONAL NORMALS.
&&
.AVIATION...FOR THE 00Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
MONDAY THROUGH WEDNESDAY...THERE WILL BE SLIGHT CHANCES OF MAINLY
AFTERNOON AND EVENING THUNDERSTORMS...PRIMARILY OVER THE HIGHER
TERRAIN OF NORTHERN ARIZONA THROUGH THE PERIOD.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JJ
AVIATION/FIRE WX.....STAUDENMAIER
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KTWC 052015
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
115 PM MST FRI SEP 5 2008
.SYNOPSIS...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING LATE SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK.
&&
.DISCUSSION...A DRY AIRMASS IN PLACE WITH THIS MORNINGS KTWC
SOUNDING SHOWING A PWAT OF ONLY 0.77 INCHES. THIS IS DOWN 0.37
INCHES IN 24 HOURS. WITH THAT SAID...WE ARE DRY ENOUGH TO PRECLUDE
THE DEVELOPMENT OF ANY STORMS FOR THIS AFTERNOON AND EVENING...AND
THIS WILL CONTINUE THROUGH SATURDAY.
BY SUNDAY THE MODELS SHOW A LOW DEVELOPING ALONG THE CALIFORNIA
COAST WITH SOME POTENTIAL FOR MOISTURE TO INCREASE AS THE LOW TO MID
LEVEL FLOW TRIES TO BECOME MORE SOUTHERLY...AND A PIECE OF ENERGY
SWINGS THROUGH THE STATE AND TO OUR NORTHEAST BY TUESDAY.
BOTH THE GFS AND ECMWF SHOW ANOTHER TROUGH DROPPING SOUTH FROM THE
PAC NW/WESTERN CANADA. THIS SYSTEM IS PROGGED TO LIE ACROSS IDAHO...
NEVADA AND SOUTH CENTRAL CALIFORNIA BY LATE IN THE AFTERNOON ON
WEDNESDAY.
THE 12Z RUN OF THE ECMWF IS NOW MORE IN LINE WITH THE 12Z RUN OF THE
GFS...BUT STILL WITH SOME SIGNIFICANT DIFFERENCES. THE GFS SHOWS THE
MAIN MID TO UPPER LEVEL VORT MAX HEADING INTO THE MIDWEST BY LATE
THURSDAY...WHILE THE ECMWF SHOWS THE VORT MAX OVER SE WYOMING AND
INTO NE UTAH. BOTH MODELS CUTOFF A LOW OFFSHORE OF SOUTHERN
CALIFORNIA ON THURSDAY WITH A LARGE RIDGE OVER NE MEXICO AND SRN
TEXAS WHICH WILL RESULT IN SW FLOW ACROSS THE DESERT SOUTHWEST.
BY FRIDAY THE MODELS SHOW A SIMILAR SETUP WITH A RIDGE TO OUR SE AND
A LOW TO OUR WEST...BUT THE ECMWF HAS THE LOW OFF THE SRN CALIFORNIA
COAST ABOUT 300 MILES...BUT THE GFS HAS THE LOW ABOUT 800 MILES TO
THE WEST OF THE SRN CALIFORNIA COAST. IT IS LIKELY THAT SOME
MOISTURE INCREASE WILL LIKELY BEGIN LATE SUNDAY AND CONTINUE THROUGH
THE WEEK AS THE TROUGHINESS PERSISTS TO OUR WEST...BUT THERE ARE
ENOUGH DIFFERENCES TO JUST HOLD ON TO THE SLIGHT CHANCE POPS FOR
GENERALLY MONDAY THROUGH THURSDAY...MAINLY ALONG THE NEW MEXICO
BORDER.
HIGHS WILL BE 5 TO 7 DEGS ABOVE NORMAL FOR SATURDAY...AND 3 TO 5
DEGS ABOVE NORMAL FOR SUNDAY AND MONDAY. THEREAFTER...EXPECT HIGHS
TO HOVER NEAR NORMAL. LOWS WILL BE AT OR SLIGHTLY BELOW NORMAL FOR
TONIGHT/EARLY SATURDAY...THEN 2 TO 4 DEGS ABOVE NORMAL EACH MORNING
THROUGH NEXT FRIDAY.
&&
.AVIATION...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK. OTHERWISE...
EXPECT LIGHT DIURNALLY DRIVEN SURFACE WINDS TONIGHT AND SATURDAY.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
MOLLERE
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 051700
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
FAIRLY DRY AIR WILL REMAIN OVER THE REGION THROUGH SATURDAY
RESULTING IN CLEAR SKIES...HOT DAYS...AND COOL NIGHTS. BY SUNDAY A
LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST BRINGING AN INCREASE
IN CLOUDS. SLIGHT CHANCES FOR RAIN WILL RETURN TO THE EASTERN
ARIZONA MOUNTAINS MONDAY AND REMAIN THROUGH THE WEEK. THIS SYSTEM
WILL ALSO BRING COOLER AIR TO THE REGION WITH MORE FALL-LIKE
TEMPERATURES EXPECTED BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
A WEAK AREA OF LOW PRESSURE OFF THE BAJA COAST THIS MORNING WAS
ACTUALLY CREATING SOME CLOUDINESS TO OUR SW...ALONG WITH AN ISOLD
TSTM OR TWO OFF THE NRN BAJA. OVER AZ/SE CA...AMS IS DRIER THAN 24
HOURS AGO...AND AS A RESULT SKIES ARE STARTING OUT VERY CLEAR PER
LATEST SATELLITE IMAGERY. 12Z MODEL RUNS ARE KEEPING THE BAJA
MOISTURE AWAY FROM OUR AREA...IN FACT RH PROGS FROM THE NAM AND GFS
WOULD INDICATE THIS MOISTURE WILL BE TRANSPORTED FURTHER TO THE WEST
AS UPPER LOW GETS CAUGHT UNDER ERN PAC RIDGE. THIS MEANS OUR CWA
SHOULD REMAIN ON THE DRY SIDE OF THE SUBTROPICAL RIDGE...WITH WARM
DAYS AND CLEAR MILD NIGHTS IN STORE THRU THE WEEKEND. STILL KEEPING
OUR EYES ON POTENTIAL TROUGHING PROGGED TO TAKE PLACE OFF THE W
COAST NEXT WEEK. THIS MAY HELP TO ADVECT SOME MORE SIGNIFICANT MSTR
BACK INTO AZ FROM THE SE...STAY TUNED. FOR NOW...CURRENT FORECASTS
APPEAR TO BE IN GREAT SHAPE...NO UPDATES NEEDED.
PREVIOUS DISCUSSION...
FAVORED MODELS FOR THIS FORECAST PACKAGE INCLUDES A BLEND OF THE 00Z
NAM...18Z DGEX...00Z ECMWF...AND 00Z GFS ENS.
A VERY BROAD TROUGH WILL EXIST ACROSS NORTH AMERICA FOR MUCH OF THE
NEXT WEEK. FOR THE NEXT FEW DAYS THE NW FLOW WILL KEEP A DRY AIRMASS
IN PLACE ACROSS OR CWA. THE BIG STORY TODAY AND TOMORROW WILL BE
THE ABNORMALLY WARM/HOT TEMPERATURES. AREAS OF SE CA/SW AZ COULD BE
FLIRTING WITH RECORD HIGH TEMPS THROUGH SATURDAY...POSSIBLY INTO
SUNDAY...DUE TO A RATHER DRY PBL AND AMPLE SOLAR INSOLATION. NO
EXCESSIVE HEAT WARNING REQUIRED AT THIS TIME BUT WILL HIGHLIGHT THE
HEAT WITH A HEADLINE IN THE ZONES AND IN A HAZARDOUS WEATHER OUTLOOK
LATER THIS MORNING.
BY SUNDAY A WEAK CUT-OFF LOW NEAR LAX WILL GET PICKED-UP BY A
SHORTWAVE MOVING DOWN IN THE NW FLOW FROM THE PAC NW. THIS LOW WILL
BEGIN TO IMPORT SOME MID-LEVEL MOISTURE INTO AZ. WHILE THE MOISTURE
IS NOT IMPRESSIVE THE PBL WILL BE VERY WARM AND VERY DEEP SO WE/LL
LIKELY SEE SOME MOUNTAIN TSTMS ACROSS ERN AZ SUNDAY
AFTERNOON/EVENING. PROBABLY ONLY MTNS OF ABOUT 8K FEET AND HIGHER SO
NOT IN OUR CWA. STORM MOTION WILL BE OFF TO THE NE SO NO CHANCE OF
STORMS MOVING INTO THE LOWER ELEVATIONS...WHICH WOULD BE EXTREMELY
HOSTILE TO STORMS ANYWAYS.
MONDAY MID-LEVEL MOISTURE CONTINUES TO INCREASE ACROSS AZ. A NICE
DIFLUENT AREA SETS UP IN AN ARC FROM LAS TO ELP. BETTER CHANCE OF
MOUNTAIN STORMS IN OUR CWA MONDAY SO INCREASED POPS INTO THE SLIGHT
CHANCE TERRITORY. RATHER COMPLICATED PATTERN WILL BE UNFOLDING
MONDAY AS ANOTHER SHORTWAVE DROPS INTO THE BACKSIDE OF THE CUT-OFF
LOW...WHICH WILL HELP EJECT THE CUT-OFF LOW TO THE EAST ON TUESDAY.
AGAIN PRECIP CHANCES WILL MAINLY BE N/E OF OUR CWA. APPEARS THAT A
SIGNIFICANT DRY PUNCH WILL DEVELOP TUESDAY AND SPREAD ACROSS SE
CA/SW AZ.
THE KICKER SHORTWAVE DEVELOPS A BIT MORE ON WEDNESDAY AS IT MOVES
SOUTHWARD ALONG THE CA COAST...THEN MOVE ACROSS AZ ON THURSDAY.
LOOKS LIKE IT/LL PULL IN SOME MOISTURE FROM THE SOUTH BUT THE
MOISTURE MAY NOT GET WRAPPED IN UNTIL THE SHORTWAVE IS ALMOST EAST
OF OUR AREA. SOME SHORTWAVE ENERGY/TROUGHING REMAINS OVER THE AREA
INTO FRIDAY WITH THE DRY SLOT STILL SEEMINGLY IN PLACE. OTHER
POSSIBLE INTERESTING FEATURE AT THE END OF NEXT WEEK IS A TROPICAL
SYSTEM THE MODELS ARE TRYING TO SPIN-UP. LOW PROBABILITY EVENT RIGHT
NOW BUT WILL BEAR WATCHING.
AFTER A WARM/HOT WEEKEND TEMPERATURES NEXT WEEK WILL BE COOLING TO
NEAR OR JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...
QUIESCENT CONDITIONS EXPECTED THROUGH AT LEAST SATURDAY...WITH
MOSTLY CLEAR SKIES AND LIGHT DIURNALLY DRIVEN WINDS. FURTHER DRYING
OF THE ATMOSPHERE WILL PRECLUDE ANY ISOLATED THUNDERSTORM
DEVELOPMENT IN HIGHER TERRAIN AREAS THIS AFTERNOON. NO AVIATION
WEATHER CONCERNS ANTICIPATED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY..BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...ESTLE/INIGUEZ
AVIATION...ROGERS
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 051620
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
917 AM MST FRI SEP 5 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...A HIGH PRESSURE RIDGE WILL REMAIN OVER THE STATE
THROUGH SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH MAINLY CLEAR
SKIES...WARM AFTERNOONS AND COOL NIGHTS.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH RESPONSIBLE FOR THE NORTHWEST FLOW OVER ARIZONA MOVES EAST
AND A WEAK TROUGH OF LOW PRESSURE LINGERS OFF THE WEST COAST. A
HIGH PRESSURE CENTER IS ALSO EXPECTED TO BUILD OVER THE WESTERN GULF
OF MEXICO THROUGH EARLY IN THE WEEK. THE AIR FLOW OVER ARIZONA
SHOULD TURN MORE SOUTHERLY...DRAWING UP MOISTURE AND INCREASING THE
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. STORM CHANCES
FOR SUNDAY LOOK SLIM BASED ON FORECAST SOUNDINGS...MAINLY AFFECTING
THE WHITE MTNS AND EASTERN MOGOLLON RIM WITH SOME HIGH-BASED
ACTIVITY. FOR MONDAY AND TUESDAY...LOW LEVEL MOISTURE SHOULD
INCREASE...BRINGING A BETTER CHANCE OF SHOWERS AND STORMS.
FOR WEDNESDAY THROUGH FRIDAY...FORECAST MODEL SOLUTIONS BEGIN TO
DIFFER IN THE HANDLING OF A SHORTWAVE TROUGH MOVING INTO THE PACIFIC
NW. THE ECMWF DIGS THE SYSTEM SOUTHWARD INTO THE GREAT BASIN WHICH
WOULD LIKELY RESULT IN ADDITIONAL MOISTURE BEING PULLED INTO
ARIZONA. THE GFS AND MOST ENSEMBLES TAKE MOST OF THE SHORTWAVE
ENERGY ACROSS THE NORTHERN PLAINS...WITH ONLY WEAK TROUGHING OVER
THE GREAT BASIN AND SOMEWHAT LESS MOISTURE FOR OUR REGION. FOR
NOW...WE`LL LEAN TOWARD THE ECMWF AND KEEP LOW RAIN CHANCES IN THE
FORECAST EACH DAY THROUGH THE END OF THE WEEK...ALONG WITH SLIGHTLY
BELOW NORMAL TEMPERATURES.
&&
.AVIATION...FOR THE 18Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
SUNDAY THROUGH TUESDAY...THERE WILL BE SLIGHT CHANCES OF MAINLY
AFTERNOON AND EVENING THUNDERSTORMS...PRIMARILY OVER THE HIGHER
TERRAIN OF NORTHERN ARIZONA THROUGH THE PERIOD...ESPECIALLY THE
EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JJ
AVIATION/FIRE WX.....STAUDENMAIER
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KFGZ 051620
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
917 AM MST FRI SEP 5 2008
.SYNOPSIS...A HIGH PRESSURE RIDGE WILL PRODUCE A DRY WEATHER PATTERN
WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SUNDAY. BY
MONDAY...A SOUTHERLY FLOW WILL BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...A HIGH PRESSURE RIDGE WILL REMAIN OVER THE STATE
THROUGH SATURDAY. THIS WILL RESULT IN DRY WEATHER WITH MAINLY CLEAR
SKIES...WARM AFTERNOONS AND COOL NIGHTS.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH RESPONSIBLE FOR THE NORTHWEST FLOW OVER ARIZONA MOVES EAST
AND A WEAK TROUGH OF LOW PRESSURE LINGERS OFF THE WEST COAST. A
HIGH PRESSURE CENTER IS ALSO EXPECTED TO BUILD OVER THE WESTERN GULF
OF MEXICO THROUGH EARLY IN THE WEEK. THE AIR FLOW OVER ARIZONA
SHOULD TURN MORE SOUTHERLY...DRAWING UP MOISTURE AND INCREASING THE
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. STORM CHANCES
FOR SUNDAY LOOK SLIM BASED ON FORECAST SOUNDINGS...MAINLY AFFECTING
THE WHITE MTNS AND EASTERN MOGOLLON RIM WITH SOME HIGH-BASED
ACTIVITY. FOR MONDAY AND TUESDAY...LOW LEVEL MOISTURE SHOULD
INCREASE...BRINGING A BETTER CHANCE OF SHOWERS AND STORMS.
FOR WEDNESDAY THROUGH FRIDAY...FORECAST MODEL SOLUTIONS BEGIN TO
DIFFER IN THE HANDLING OF A SHORTWAVE TROUGH MOVING INTO THE PACIFIC
NW. THE ECMWF DIGS THE SYSTEM SOUTHWARD INTO THE GREAT BASIN WHICH
WOULD LIKELY RESULT IN ADDITIONAL MOISTURE BEING PULLED INTO
ARIZONA. THE GFS AND MOST ENSEMBLES TAKE MOST OF THE SHORTWAVE
ENERGY ACROSS THE NORTHERN PLAINS...WITH ONLY WEAK TROUGHING OVER
THE GREAT BASIN AND SOMEWHAT LESS MOISTURE FOR OUR REGION. FOR
NOW...WE`LL LEAN TOWARD THE ECMWF AND KEEP LOW RAIN CHANCES IN THE
FORECAST EACH DAY THROUGH THE END OF THE WEEK...ALONG WITH SLIGHTLY
BELOW NORMAL TEMPERATURES.
&&
.AVIATION...FOR THE 18Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
SUNDAY THROUGH TUESDAY...THERE WILL BE SLIGHT CHANCES OF MAINLY
AFTERNOON AND EVENING THUNDERSTORMS...PRIMARILY OVER THE HIGHER
TERRAIN OF NORTHERN ARIZONA THROUGH THE PERIOD...ESPECIALLY THE
EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............JJ
AVIATION/FIRE WX.....STAUDENMAIER
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KTWC 051530
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
830 AM MST FRI SEP 5 2008
.SYNOPSIS...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK.
&&
.DISCUSSION...A DRY AIRMASS IN PLACE WITH THIS MORNINGS KTWC
SOUNDING SHOWING A PWAT OF ONLY 0.77 INCHES. THIS IS DOWN 0.37
INCHES IN 24 HOURS. WITH THAT SAID...WE ARE DRY ENOUGH TO PRECLUDE
THE DEVELOPMENT OF ANY STORMS FOR THIS AFTERNOON AND EVENING. THIS
WILL CONTINUE THROUGH SATURDAY OR SO...WITH A RETURN TO A THREAT FOR
SHOWERS PERHAPS AS EARLY AS SUNDAY...BUT ESPECIALLY BY MONDAY...AND
MAINLY ALONG THE NEW MEXICO BORDER.
THE FORECAST FOR THIS AFTERNOON AND EVENING LOOKS GOOD AND NO
CHANGES ARE PLANNED AT THIS TIME.
&&
.AVIATION...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK. OTHERWISE...
EXPECT LIGHT DIURNALLY DRIVEN SURFACE WINDS TODAY. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.PREV DISCUSSION...SOUTHEAST ARIZONA IS CURRENTLY IN A QUIET WEATHER
PATTERN FOR EARLY SEPTEMBER. THE 00Z KTWC SOUNDING DEPICTED A MUCH
DRIER PROFILE WITH A PRECIPITABLE WATER VALUE OF 0.69 INCHES.
ALTHOUGH THERE WERE A FEW STORMS IN OUR CWA YESTERDAY...WOULD NOT
EXPECT THE SAME TODAY AS EXTREME SOUTHEAST EDGE OF MEAN RIDGE OFF
THE WEST COAST NUDGES INTO OUR NECK OF THE WOODS. IT IS NOT ANY
SIGNIFICANT WARMING ALOFT...BUT ENOUGH TO TURN THINGS OFF THE NEXT
DAY OR TWO. EXPECT A WEAK IMPULSE CURRENTLY IN NORTHWEST MEXICO TO
PUSH SOME MOISTURE NORTHWEST INTO THE FAR SE CORNER OF THE STATE
SUNDAY...RESULTING IN SLIGHT CHANCE POPS SUN AFTERNOON AND EVENING.
OTHERWISE...UPPER HIGH OVER THE GULF OF MEXICO WILL TRACK WEST NEXT
WEEK RESULTING IN A WEAK SOUTHERLY FLOW. THIS WILL HELP IMPORT SOME
MOISTURE BACK INTO THE CWA THROUGH THE WEEK...WITH INCREASING
CHANCES OF PRECIPITATION AS WE MOVE THROUGH THE WORK WEEK. 00Z GFS
INDICATING TROPICAL MOISTURE MAY MOVE UP THE GULF OF CA THE SECOND
HALF OF NEXT WEEK AS DISTURBANCE MOVES WEST OF BAJA. HARD TO JUMP ON
ANYTHING RIGHT NOW CONSIDERING PERFORMANCE OF MODELS IN EXTENDED
PERIODS THIS TIME OF YEAR...BUT TRENDING POPS UP THROUGH NEXT WEEK
LOOKS PRUDENT AT THIS TIME.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
MOLLERE
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 051142
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
440 AM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSION.
&&
.SYNOPSIS...
FAIRLY DRY AIR WILL REMAIN OVER THE REGION THROUGH SATURDAY
RESULTING IN CLEAR SKY...HOT DAYS...AND COOL NIGHTS. BY SUNDAY A LOW
PRESSURE SYSTEM WILL APPROACH FROM THE WEST BRINGING AN INCREASE IN
CLOUDS. SLIGHT CHANCES FOR RAIN WILL RETURN TO THE EASTERN ARIZONA
MOUNTAINS MONDAY AND REMAIN THROUGH THE WEEK. THIS SYSTEM WILL ALSO
BRING COOLER AIR TO THE REGION WITH MORE FALL LIKE TEMPERATURES
EXPECTED BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
FAVORED MODELS FOR THIS FORECAST PACKAGE INCLUDES A BLEND OF THE 00Z
NAM...18Z DGEX...00Z ECMWF...AND 00Z GFS ENS.
A VERY BROAD TROUGH WILL EXIST ACROSS NORTH AMERICA FOR MUCH OF THE
NEXT WEEK. FOR THE NEXT FEW DAYS THE NW FLOW WILL KEEP A DRY AIRMASS
IN PLACE ACROSS OR CWA. THE BIG STORY TODAY AND TOMORROW WILL BE
THE ABNORMALLY WARM/HOT TEMPERATURES. AREAS OF SE CA/SW AZ COULD BE
FLIRTING WITH RECORD HIGH TEMPS THROUGH SATURDAY...POSSIBLY INTO
SUNDAY...DUE TO A RATHER DRY PBL AND AMPLE SOLAR INSOLATION. NO
EXCESSIVE HEAT WARNING REQUIRED AT THIS TIME BUT WILL HIGHLIGHT THE
HEAT WITH A HEADLINE IN THE ZONES AND IN A HAZARDOUS WEATHER OUTLOOK
LATER THIS MORNING.
BY SUNDAY A WEAK CUT-OFF LOW NEAR LAX WILL GET PICKED-UP BY A
SHORTWAVE MOVING DOWN IN THE NW FLOW FROM THE PAC NW. THIS LOW WILL
BEGIN TO IMPORT SOME MID-LEVEL MOISTURE INTO AZ. WHILE THE MOISTURE
IS NOT IMPRESSIVE THE PBL WILL BE VERY WARM AND VERY DEEP SO WE/LL
LIKELY SEE SOME MOUNTAIN TSTMS ACROSS ERN AZ SUNDAY
AFTERNOON/EVENING. PROBABLY ONLY MTNS OF ABOUT 8K FEET AND HIGHER SO
NOT IN OUR CWA. STORM MOTION WILL BE OFF TO THE NE SO NO CHANCE OF
STORMS MOVING INTO THE LOWER ELEVATIONS...WHICH WOULD BE EXTREMELY
HOSTILE TO STORMS ANYWAYS.
MONDAY MID-LEVEL MOISTURE CONTINUES TO INCREASE ACROSS AZ. A NICE
DIFLUENT AREA SETS UP IN AN ARC FROM LAS TO ELP. BETTER CHANCE OF
MOUNTAIN STORMS IN OUR CWA MONDAY SO INCREASED POPS INTO THE SLIGHT
CHANCE TERRITORY. RATHER COMPLICATED PATTERN WILL BE UNFOLDING
MONDAY AS ANOTHER SHORTWAVE DROPS INTO THE BACKSIDE OF THE CUT-OFF
LOW...WHICH WILL HELP EJECT THE CUT-OFF LOW TO THE EAST ON TUESDAY.
AGAIN PRECIP CHANCES WILL MAINLY BE N/E OF OUR CWA. APPEARS THAT A
SIGNIFICANT DRY PUNCH WILL DEVELOP TUESDAY AND SPREAD ACROSS SE
CA/SW AZ.
THE KICKER SHORTWAVE DEVELOPS A BIT MORE ON WEDNESDAY AS IT MOVES
SOUTHWARD ALONG THE CA COAST...THEN MOVE ACROSS AZ ON THURSDAY.
LOOKS LIKE IT/LL PULL IN SOME MOISTURE FROM THE SOUTH BUT THE
MOISTURE MAY NOT GET WRAPPED IN UNTIL THE SHORTWAVE IS ALMOST EAST
OF OUR AREA. SOME SHORTWAVE ENERGY/TROUGHING REMAINS OVER THE AREA
INTO FRIDAY WITH THE DRY SLOT STILL SEEMINGLY IN PLACE. OTHER
POSSIBLE INTERESTING FEATURE AT THE END OF NEXT WEEK IS A TROPICAL
SYSTEM THE MODELS ARE TRYING TO SPIN-UP. LOW PROBABILITY EVENT RIGHT
NOW BUT WILL BEAR WATCHING.
AFTER A WARM/HOT WEEKEND TEMPERATURES NEXT WEEK WILL BE COOLING TO
NEAR OR JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...
QUIESCENT CONDITIONS EXPECTED THROUGH AT LEAST SATURDAY...WITH
MOSTLY CLEAR SKIES AND LIGHT DIURNALLY DRIVEN WINDS. FURTHER DRYING
OF THE ATMOSPHERE WILL PRECLUDE ANY ISOLATED THUNDERSTORM
DEVELOPMENT IN HIGHER TERRAIN AREAS THIS AFTERNOON. NO AVIATION
WEATHER CONCERNS ANTICIPATED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH WEDNESDAY...VERY HOT TEMPERATURES CAN BE EXPECTED
SUNDAY..BEFORE A GRADUAL COOLING TREND WILL COMMENCE...BRINGING
TEMPERATURES TO NEAR SEASONAL NORMALS TUESDAY AND WEDNESDAY. DRY
CONDITIONS WILL CONTINUE...WITH AFTERNOON RH VALUES FALLING TO NEAR
15 PERCENT ACROSS THE LOWER DESERTS...AND ONLY MODEST OVERNIGHT
RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE GUSTS
DURING THE DAY. A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE
COAST OF SOUTHERN CALIFORNIA...RETURNING A SLIGHT CHANCE OF
THUNDERSTORMS TO SOUTHERN GILA COUNTY EACH DAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...INIGUEZ
AVIATION...ROGERS
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 051015
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
315 AM MST FRI SEP 5 2008
.SYNOPSIS...NORTHWESTERLY FLOW ALOFT WILL PRODUCE A DRY WEATHER
PATTERN WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH SATURDAY.
BY SUNDAY...A SOUTHERLY FLOW IS EXPECTED TO BEGIN DEVELOPING...BRINGING
INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND THUNDERSTORMS.
&&
.DISCUSSION...
SKIES ARE CLEAR ACROSS NORTHERN ARIZONA THIS MORNING. THE 00Z KFGZ
SOUNDING HAD 0.30 PW AND THE SATELLITE GOES PW IS SHOWING 0.30 TO
AROUND 0.40 THIS MORNING. THE DEEP AND DRY WEST TO NORTHWEST FLOW IS
EXPECTED TO REMAIN OVER NORTHERN ARIZONA THROUGH SATURDAY.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE ON SUNDAY AS THE
TROUGH RESPONSIBLE FOR THE NORTHWEST FLOW OVER ARIZONA MOVES EAST. A
WEAK TROUGH OF LOW PRESSURE IS FORECAST DEVELOP OFF THE WEST COAST
ON SUNDAY. A HIGH PRESSURE CENTER IS ALSO EXPECTED TO BUILD OVER THE
WESTERN GULF OF MEXICO THROUGH EARLY IN THE WEEK. THE AIR FLOW OVER
ARIZONA SHOULD TURN MORE SOUTHERLY...DRAWING UP MOISTURE AND
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK.
THERE ARE INDICATIONS THAT A STRONGER LOW PRESSURE CENTER COULD
DEVELOP ALONG THE WEST COAST BY LATE NEXT WEEK THAT WOULD DRAW MORE
MOISTURE OVER ARIZONA. IT IS TOO EARLY GO WITH THIS SOLUTION YET.
WILL ONLY MAKE MINOR UPWARD ADJUSTMENTS TO THE CHANCES IN
PRECIPITATION SUNDAY AND MONDAY AT THIS TIME.
&&
.AVIATION...FOR THE 12Z PACKAGE...GENERALLY CLEAR SKIES AND LIGHT
SURFACE WINDS OF LESS THAN 15 KTS ARE EXPECTED FOR THE NEXT 24
HOURS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
SUNDAY THROUGH TUESDAY...CONTINUED DRY CONDITIONS ARE EXPECTED TO
LAST THROUGH THE FORECAST PERIOD...HOWEVER...THERE IS A SLIGHT
CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ALONG THE
HIGHER ELEVATIONS OF THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............MAS
AVIATION/FIRE WX.....JVC
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
000
FXUS65 KPSR 050900
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
200 AM MST FRI SEP 5 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
FAIRLY DRY AIR WILL REMAIN OVER THE REGION THROUGH SATURDAY
RESULTING IN CLEAR SKY...HOT DAYS...AND COOL NIGHTS. BY SUNDAY A LOW
PRESSURE SYSTEM WILL APPROACH FROM THE WEST BRINGING AN INCREASE IN
CLOUDS. SLIGHT CHANCES FOR RAIN WILL RETURN TO THE EASTERN ARIZONA
MOUNTAINS MONDAY AND REMAIN THROUGH THE WEEK. THIS SYSTEM WILL ALSO
BRING COOLER AIR TO THE REGION WITH MORE FALL LIKE TEMPERATURES
EXPECTED BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...
FAVORED MODELS FOR THIS FORECAST PACKAGE INCLUDES A BLEND OF THE 00Z
NAM...18Z DGEX...00Z ECMWF...AND 00Z GFS ENS.
A VERY BROAD TROUGH WILL EXIST ACROSS NORTH AMERICA FOR MUCH OF THE
NEXT WEEK. FOR THE NEXT FEW DAYS THE NW FLOW WILL KEEP A DRY AIRMASS
IN PLACE ACROSS OR CWA. THE BIG STORY TODAY AND TOMORROW WILL BE
THE ABNORMALLY WARM/HOT TEMPERATURES. AREAS OF SE CA/SW AZ COULD BE
FLIRTING WITH RECORD HIGH TEMPS THROUGH SATURDAY...POSSIBLY INTO
SUNDAY...DUE TO A RATHER DRY PBL AND AMPLE SOLAR INSOLATION. NO
EXCESSIVE HEAT WARNING REQUIRED AT THIS TIME BUT WILL HIGHLIGHT THE
HEAT WITH A HEADLINE IN THE ZONES AND IN A HAZARDOUS WEATHER OUTLOOK
LATER THIS MORNING.
BY SUNDAY A WEAK CUT-OFF LOW NEAR LAX WILL GET PICKED-UP BY A
SHORTWAVE MOVING DOWN IN THE NW FLOW FROM THE PAC NW. THIS LOW WILL
BEGIN TO IMPORT SOME MID-LEVEL MOISTURE INTO AZ. WHILE THE MOISTURE
IS NOT IMPRESSIVE THE PBL WILL BE VERY WARM AND VERY DEEP SO WE/LL
LIKELY SEE SOME MOUNTAIN TSTMS ACROSS ERN AZ SUNDAY
AFTERNOON/EVENING. PROBABLY ONLY MTNS OF ABOUT 8K FEET AND HIGHER SO
NOT IN OUR CWA. STORM MOTION WILL BE OFF TO THE NE SO NO CHANCE OF
STORMS MOVING INTO THE LOWER ELEVATIONS...WHICH WOULD BE EXTREMELY
HOSTILE TO STORMS ANYWAYS.
MONDAY MID-LEVEL MOISTURE CONTINUES TO INCREASE ACROSS AZ. A NICE
DIFLUENT AREA SETS UP IN AN ARC FROM LAS TO ELP. BETTER CHANCE OF
MOUNTAIN STORMS IN OUR CWA MONDAY SO INCREASED POPS INTO THE SLIGHT
CHANCE TERRITORY. RATHER COMPLICATED PATTERN WILL BE UNFOLDING
MONDAY AS ANOTHER SHORTWAVE DROPS INTO THE BACKSIDE OF THE CUT-OFF
LOW...WHICH WILL HELP EJECT THE CUT-OFF LOW TO THE EAST ON TUESDAY.
AGAIN PRECIP CHANCES WILL MAINLY BE N/E OF OUR CWA. APPEARS THAT A
SIGNIFICANT DRY PUNCH WILL DEVELOP TUESDAY AND SPREAD ACROSS SE
CA/SW AZ.
THE KICKER SHORTWAVE DEVELOPS A BIT MORE ON WEDNESDAY AS IT MOVES
SOUTHWARD ALONG THE CA COAST...THEN MOVE ACROSS AZ ON THURSDAY.
LOOKS LIKE IT/LL PULL IN SOME MOISTURE FROM THE SOUTH BUT THE
MOISTURE MAY NOT GET WRAPPED IN UNTIL THE SHORTWAVE IS ALMOST EAST
OF OUR AREA. SOME SHORTWAVE ENERGY/TROUGHING REMAINS OVER THE AREA
INTO FRIDAY WITH THE DRY SLOT STILL SEEMINGLY IN PLACE. OTHER
POSSIBLE INTERESTING FEATURE AT THE END OF NEXT WEEK IS A TROPICAL
SYSTEM THE MODELS ARE TRYING TO SPIN-UP. LOW PROBABILITY EVENT RIGHT
NOW BUT WILL BEAR WATCHING.
AFTER A WARM/HOT WEEKEND TEMPERATURES NEXT WEEK WILL BE COOLING TO
NEAR OR JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...
VERY LITTLE CLOUDINESS ANTICIPATED THROUGH 06Z SATURDAY. CONTINUED
DECLINE IN MOISTURE ANTICIPATED TO END THE PRESENCE OF THE ISOLATED
WEAK AFTERNOON THUNDERSTORMS THAT HAVE BEEN OCCURRING THE PAST
COUPLE DAYS. EXPECT LIGHT SURFACE WINDS THE REST OF THE NIGHT AND
THROUGH FRIDAY WITH A REPEAT OF THURSDAYS PATTERNS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES AND DRY
CONDITIONS CAN BE EXPECTED THIS WEEKEND. AFTERNOON RH VALUES WILL
FALL BELOW 15 PERCENT ACROSS THE LOWER DESERTS...WITH ONLY MODEST
OVERNIGHT RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE
GUSTS DURING THE DAY. MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL
DEVELOP AND MOVE TOWARDS ARIZONA...WITH A SLIGHT CHANCE OF
THUNDERSTORMS RETURNING TO SOUTHERN GILA COUNTY...AND TEMPERATURES
COOLING TO NEAR SEASONAL NORMALS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...INIGUEZ
AVIATION...AJ
FIRE WEATHER...ROGERS
000
FXUS65 KTWC 050759
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
100 AM MST FRI SEP 5 2008
.SYNOPSIS...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK.
&&
.DISCUSSION...SOUTHEAST ARIZONA IS CURRENTLY IN A QUIET WEATHER
PATTERN FOR EARLY SEPTEMBER. THE 00Z KTWC SOUNDING DEPICTED A MUCH
DRIER PROFILE WITH A PRECIPITABLE WATER VALUE OF 0.69 INCHES.
ALTHOUGH THERE WERE A FEW STORMS IN OUR CWA YESTERDAY...WOULD NOT
EXPECT THE SAME TODAY AS EXTREME SOUTHEAST EDGE OF MEAN RIDGE OFF
THE WEST COAST NUDGES INTO OUR NECK OF THE WOODS. IT IS NOT ANY
SIGNIFICANT WARMING ALOFT...BUT ENOUGH TO TURN THINGS OFF THE NEXT
DAY OR TWO. EXPECT A WEAK IMPULSE CURRENTLY IN NORTHWEST MEXICO TO
PUSH SOME MOISTURE NORTHWEST INTO THE FAR SE CORNER OF THE STATE
SUNDAY...RESULTING IN SLIGHT CHANCE POPS SUN AFTERNOON AND EVENING.
OTHERWISE...UPPER HIGH OVER THE GULF OF MEXICO WILL TRACK WEST NEXT
WEEK RESULTING IN A WEAK SOUTHERLY FLOW. THIS WILL HELP IMPORT SOME
MOISTURE BACK INTO THE CWA THROUGH THE WEEK...WITH INCREASING
CHANCES OF PRECIPITATION AS WE MOVE THROUGH THE WORK WEEK. 00Z GFS
INDICATING TROPICAL MOISTURE MAY MOVE UP THE GULF OF CA THE SECOND
HALF OF NEXT WEEK AS DISTURBANCE MOVES WEST OF BAJA. HARD TO JUMP ON
ANYTHING RIGHT NOW CONSIDERING PERFORMANCE OF MODELS IN EXTENDED
PERIODS THIS TIME OF YEAR...BUT TRENDING POPS UP THROUGH NEXT WEEK
LOOKS PRUDENT AT THIS TIME.
&&
.AVIATION...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...MOISTURE WILL SLOWLY AND GRADUALLY MOVE
BACK INTO SOUTHEAST ARIZONA BEGINNING SUNDAY....RESULTING IN A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEXT WEEK. OTHERWISE...
EXPECT LIGHT DIURNALLY DRIVEN SURFACE WINDS TODAY. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
000
FXUS65 KTWC 050404
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
903 PM MST THU SEP 4 2008
.SYNOPSIS...DRIER AIR HAS SETTLED ACROSS SOUTHEAST ARIZONA WHICH
WILL RESULT IN MOSTLY CLEAR SKIES INTO THIS WEEKEND WITH HOTTER
AFTERNOONS. THEREAFTER...A LOW PRESSURE SYSTEM MAY BRING A FEW
SHOWERS BACK TO MAINLY HIGHER TERRAIN NEXT WEEK.
&&
.DISCUSSION...DRIER AIR HAS FINALLY SETTLED INTO SOUTHEAST ARIZONA
THIS EVENING. THE 00Z KTWC SOUNDING INDICATES THE PRECIPITABLE WATER
VALUE HAS DROPPED TO 0.69 INCHES. LATEST IR SATELLITE IMAGERY AND
KEMX RADAR IMAGERY ALSO SHOWS THAT THE FEW SHOWERS AND ISOLATED
THUNDERSTORMS THAT DID DEVELOP THIS AFTERNOON QUICKLY DISSIPATED
AROUND SUNSET. THIS DRIER AIR WILL REMAIN OVER SOUTHEAST ARIZONA
THROUGH THIS WEEKEND RESULTING IN DRY AND WARM WEATHER BEFORE SOME
MOISTURE RETURNS NEXT WEEK.
&&
.AVIATION...MOSTLY CLEAR SKIES WILL CONTINUE THE REMAINDER OF
TONIGHT AND FRIDAY. LIGHT DIURNALLY DRIVEN SURFACE WINDS ARE
EXPECTED AS WELL. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.PREV DISCUSSION...MODELS DRY US OUT THROUGH AT LEAST SUNDAY...THEN
A PACIFIC SYSTEM ALONG THE CALIFORNIA COAST IS EXPECTED TO BRING
SOME RAIN THREAT BACK IN AS IT PULLS MOISTURE FROM THE SOUTH...BUT
FOR NOW THE GFS AND ECMWF HAVE THEIR DIFFERENCES. I JUST TWEAKED THE
INHERITED POP FORECAST FOR MONDAY THROUGH THURSDAY...WHICH MAINLY
SHOWS SINGLE DIGIT TO ISOLATED POPS EACH AFTERNOON AND EVENING AND
MAINLY FROM TUCSON EAST. STILL PLENTY OF TIME TO MAKE CHANGES IF THE
MODELS HOLD ON TO THE NOTION OF A WET WEEK.
HIGHS GENERALLY 3 TO 5 DEGS ABOVE NORMAL THROUGH MONDAY...THEN NEAR
NORMAL FOR TUESDAY THROUGH THURSDAY. LOWS WILL BE 1 TO 4 DEGS ABOVE
NORMAL THROUGH THE FORECAST PERIOD...BUT THE WARMEST MORNINGS WILL
BE TUESDAY AND WEDNESDAY OF NEXT WEEK.
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
000
FXUS65 KPSR 050353
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
850 PM MST THU SEP 4 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.SYNOPSIS...
CLEAR NIGHTS AND SUNNY DAYS ARE EXPECTED TONIGHT THROUGH SATURDAY AS
MUCH DRIER AIR FROM THE NORTHWEST MOVES INTO OUR AREA. AFTERNOON HIGH
TEMPERATURES WILL RISE A DEGREE OR SO FRIDAY AND AGAIN SATURDAY WHILE
EARLY MORNING LOW TEMPERATURES STAY NEAR THE SAME OR DROP SLIGHTLY. A
WEAK PACIFIC LOW PRESSURE SYSTEM IS EXPECTED TO APPROACH OUR AREA
FROM THE WEST AND BRING SOMEWHAT LOWER TEMPERATURES EARLY NEXT WEEK
WITH A SLIGHT CHANCE OF MOUNTAIN SHOWERS AND THUNDERSTORMS AFTER THE
WEEKEND.
&&
.DISCUSSION...
SURFACE DEW POINTS HAVE BEGUN TO REBOUND AS BOUNDARY LAYER MIXING
REVERSES. SATELLITE IMAGERY SHOWS BROAD UPPER LEVEL TROUGHING OVER
MUCH OF THE CONUS WITH A NORTHEAST PACIFIC RIDGE CENTERED WEST OF
VANCOUVER ISLAND B.C. UNDERNEATH THE RIDGE ARE VARIOUS CYCLONIC
CIRCULATIONS INCLUDING AN AREA NEAR 30N LATITUDE JUST WEST OF THE
CALIFORNIA/BAJA MEXICO COAST. 00Z PSR RAOB SHOWS WHY LOCAL DEW
POINTS DROPPED INTO THE 30S THIS AFTERNOON.
LATEST PROGS SHOW CONTINUED DECLINE OF LOW LEVEL MOISTURE OVER THE
FORECAST AREA. THIS SHOULD END THE LINGERING WEAK CB DEVELOPMENT OF
THE PAST COUPLE DAYS. PROGS ALSO SHOW THE PACIFIC RIDGE TRYING TO
MOVE INLAND BUT STRUGGLING TO DO SO. INSTEAD...THE CYCLONIC
CIRCULATION AREA CURRENTLY JUST TO THE WEST EXPANDS INTO ARIZONA.
THE 00Z NAM SHOWS A MOISTURE RETURN INTO THE SOUTHEASTERN THIRD OF
THE STATE BEGINNING SATURDAY NIGHT AND GETTING INTO ZONE 24 BY
SUNDAY EVENING. TOO PREMATURE AT THIS POINT TO INTRODUCE POPS INTO
OUR FORECAST AREA FOR SUNDAY. OTHERWISE...SLIGHTLY WARMER
TEMPERATURES STILL LOOK GOOD FOR FRIDAY WITH LITTLE CHANGE SATURDAY.
PREVIOUS DISCUSSION...
THERE WERE SOME BUILDING AND TOWERING CUMULUS CLOUDS OVER THE
MOUNTAINS...AND THERE WERE ISOLATED SHOWERS OVER THE MOUNTAINS OF
SOUTHERN GILA COUNTY AND IN YUMA COUNTY ALONG THE MEXICAN BORDER...
OTHERWISE IT WAS SUNNY EARLY THIS AFTERNOON. TEMPERATURES WERE CLOSE
TO THE SAME OR A COUPLE OF DEGREES WARMER EARLY THIS AFTERNOON
COMPARED WITH THE SAME TIME YESTERDAY. IT WAS DRIER WITH DEW POINT
TEMPERATURES SEVERAL DEGREES LOWER IN SOME LOCATIONS.
THE CENTER OF HIGH PRESSURE ALOFT WILL GENERALLY REMAIN ANCHORED
OVER THE PACIFIC WEST OF NORTHERN CALIFORNIA NEAR 40 DEGREES NORTH
LATITUDE...140 DEGREES WEST LONGITUDE AT LEAST THROUGH THE COMING
WEEKEND. AT THE SAME TIME...A BROAD AREA OF LOW PRESSURE WILL BE
OVER AT LEAST THE NORTH PORTION OF THE CENTRAL UNITED STATES. BETWEEN
THESE TWO SYSTEMS...A FLOW ALOFT MOVING AROUND THE PERIPHERY OF THE
HIGH FROM THE NORTHWEST...AND EVENTUALLY NORTHEAST...WILL BRING DRIER
AIR INTO OUR AREA FRIDAY WITH EVEN DRIER AIR SATURDAY. THIS MEANS
GENERALLY CLEAR NIGHTS AND SUNNY DAYS THROUGH THE END OF THE WEEK.
THE MUCH DRIER AIR WILL CAUSE AFTERNOON DEW POINT TEMPERATURES TO
DROP AT INTO THE 30S AND POSSIBLY EVEN THE 20S BY SATURDAY. THIS
MEANS THAT EVAPORATIVE COOLERS WILL BECOME QUITE EFFECTIVE AT
COOLING THE AIR.
A SLIGHTLY WARMER AIRMASS IS EXPECTED TO CAUSE AFTERNOON HIGH
TEMPERATURES TO RISE AN ADDITIONAL DEGREE OR SO FRIDAY AND AGAIN
SATURDAY. THE MUCH DRIER AIR WILL ALSO ALLOW LOW TEMPERATURES TO STAY
NEAR THE SAME OR DROP SLIGHTLY EARLY FRIDAY MORNING.
TOWARD EARLY NEXT WEEK MORE ACTIVE WEATHER LOOKS TO RETURN. MODELS
ARE IN AGREEMENT THAT A WEAK SHORTWAVE THAT WILL MEANDER OFF THE CA
COAST THIS WEEK WILL GET PICKED-UP BY A SECOND SHORTWAVE DROPPING
OUT OF THE PAC NW. SLY FLOW WILL BE INCREASING SUNDAY WHICH WILL
SPREAD SOME MID/HIGH LEVEL MOISTURE INTO OUR AREA RESULTING IN
INCREASING CLOUDS. THE BOUNDARY LAYER WILL REMAIN DRY INTO MONDAY
THOUGH THE ATMOSPHERE WILL CONTINUE TO SLOWLY MOISTEN. THE INCREASED
MOISTURE MONDAY WILL BE ENOUGH TO WARRANT SLIGHT CHANCES FOR
SHWR/TSTMS OVER OUR FAR ERN CWA.
TUESDAY THE SYSTEM DEVELOPS A BIT MORE AND PRECIP CHANCES ARE
CURRENTLY EXPECTED TO PEAK TUESDAY. WILL LIKELY SEE A NICE DRY SLOT
FORM ON TUESDAY WHICH WILL KEEP CLOUDS AND PRECIP CHANCES LOWER OVER
OUR WRN CWA. CONVERSELY THE SYSTEM BECOMING MORE DYNAMIC WILL
INCREASE CLOUDS AND PRECIP CHANCES OVER THE ERN CWA...THOUGH STILL
KEEPING MENTION OF PRECIP TO OUR ERN MOUNTAINS /NOT IN PHX OR POINTS
WEST/. MORE UNCERTAINTY BEYOND TUESDAY AS TO HOW THE SYSTEM EVOLVES
WITH THE GFS MORE PROGRESSIVE WITH THE SYSTEM AND THE ECMWF
DEVELOPING MORE OF A CUT-OFF LOW. MORE INCLINED TO GO WITH THE GFS
AT THIS TIME DUE TO IT/S CONSISTENCY. THE OTHER BIG IMPACT OF THIS
SYSTEM WILL BE A REDUCTION IN TEMPERATURES TO NEAR OR SLIGHTLY BELOW
NORMAL VALUES.
&&
.AVIATION...
VERY LITTLE CLOUDINESS ANTICIPATED THROUGH 06Z SATURDAY. CONTINUED
DECLINE IN MOISTURE ANTICIPATED TO END THE PRESENCE OF THE ISOLATED
WEAK AFTERNOON THUNDERSTORMS THAT HAVE BEEN OCCURRING THE PAST
COUPLE DAYS. EXPECT LIGHT SURFACE WINDS THE REST OF THE NIGHT AND
THROUGH FRIDAY WITH A REPEAT OF THURSDAYS PATTERNS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES AND DRY
CONDITIONS CAN BE EXPECTED THIS WEEKEND. AFTERNOON RH VALUES WILL
FALL BELOW 15 PERCENT ACROSS THE LOWER DESERTS...WITH ONLY MODEST
OVERNIGHT RECOVERY. WINDS WILL GENERALLY BE LIGHT WITH SOME UPSLOPE
GUSTS DURING THE DAY. MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL
DEVELOP AND MOVE TOWARDS ARIZONA...WITH A SLIGHT CHANCE OF
THUNDERSTORMS RETURNING TO SOUTHERN GILA COUNTY...AND TEMPERATURES
COOLING TO NEAR SEASONAL NORMALS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...AJ/ELLIS
AVIATION...AJ
FIRE WEATHER...ROGERS
000
FXUS65 KFGZ 050319
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
825 PM MST THU SEP 4 2008
.SYNOPSIS...NORTHWESTERLY FLOW ALOFT WILL PRODUCE A DRY WEATHER
PATTERN WITH SEASONABLY WARM DAYS AND COOL NIGHTS THROUGH THE
WEEKEND. BY EARLY NEXT WEEK...SOUTHERLY FLOW IS EXPECTED TO
DEVELOP...BRINGING INCREASING MOISTURE AND A CHANCE FOR SHOWERS AND
THUNDERSTORMS.
&&
.DISCUSSION...
SKIES ARE CLEAR ACROSS NORTHERN ARIZONA THIS EVENING AS A DRY AIR
MASS IS OVERHEAD. COOL OVERNIGHT TEMPERATURES ARE IN STORE...THE
CURRENT FORECAST IS IN GOOD SHAPE WITH NO UPDATES NEEDED.
PREV DISCUSSION 225 PM MST...DEEP WEST TO NORTHWEST FLOW HAS
DEVELOPED OVER THE REGION TODAY...BRINGING A MUCH DRIER AIR MASS TO
NORTHERN ARIZONA THAT WILL CONTINUE THROUGH THE WEEKEND. THE MORNING
UPPER AIR SOUNDING AT BELLEMONT SHOWED A LARGE DECREASE IN BOUNDARY
LAYER MOISTURE SINCE WEDNESDAY MORNING...WITH PRECIPITABLE WATER
VALUES FALLING FROM .62 TO .25 INCHES. SO MOSTLY SUNNY SKIES HAVE
PREVAILED TODAY. THE DRIER AIR HAS PUSHED ALL THE WAY EAST TO THE
WHITE MTNS BASED ON SATELLITE DERIVED PRECIPITABLE WATER
IMAGES...ALTHOUGH JUST ENOUGH MOISTURE HAS LINGERED IN CENTRAL GILA
COUNTY FOR A FEW ISOLATED SHOWERS THIS AFTERNOON. ANY SHOWERS WILL
DISSIPATE QUICKLY BY LATE AFTERNOON. THE DRY AIR WILL ALSO ALLOW FOR
STRONG RADIATIONAL COOLING EACH NIGHT THROUGH THE WEEKEND...WITH
LOWS IN THE UPPER 30S TO LOW 40S OVER THE HIGHER TERRAIN...AND LOW
TO MID 30S OVER THE FAVORED COLDER SPOTS.
THE WEATHER PATTERN IS FORECAST TO BEGIN TO CHANGE BY EARLY NEXT
WEEK...POSSIBLY AS EARLY AS SUNDAY AFTERNOON OVER SOUTHERN SECTIONS.
THIS IS DUE TO WEAKENING NORTHWEST FLOW AS THE CENTRAL U.S. TROUGH
MOVES EASTWARD...AS WELL AS THE APPROACH OF A LOW PRESSURE SYSTEM
OFF THE WEST COAST. THE FLOW SHOULD TURN MORE SOUTHERLY...DRAWING UP
MOISTURE AND INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS
THROUGH MIDWEEK.
JJ
&&
.AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS AND SURFACE WINDS
LESS THAN 15 KTS ARE FORECAST FOR THE NEXT 24 HOURS. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...SEE FIRE WEATHER FORECAST (FWFFGZ) FOR DISCUSSION OF
DAYS 1 AND 2.
SUNDAY THROUGH TUESDAY...A SLIGHT CHANCE FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS MAY RETURN TO THE FORECAST AREA FOR THE
PERIOD...PRIMARILY ACROSS THE HIGHER TERRAIN OF EAST-CENTRAL
ARIZONA. IN ALL...NO OTHER CRITICAL FIRE WEATHER CONDITIONS ARE
ANTICIPATED.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...............DL
AVIATION/FIRE WX.....DL
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
| 
