000
FXUS63 KDVN 202005
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
305 PM CDT WED AUG 20 2008

.SYNOPSIS...
LOW PRESSURE IN THE SOUTHERN PLAINS FINALLY MAKING ITS MOVE TO THE
NORTHEAST WHICH WILL BE SPREADING RAIN INTO THE DVN CWA LATER
TONIGHT AND THURSDAY. MAIN TROUGH IN THE PACIFIC NORTHWEST SHOULD
SWING THROUGH THE UPPER MIDWEST THIS WEEKEND RETURNING A NORTHWEST
FLOW REGIME. THIS WILL SEND COOLER AND MUCH DRIER AIR INTO THE
REGION INTO EARLY NEXT WEEK.

&&

.SHORT TERM...TONIGHT AND THURSDAY...
SATELLITE MOVIE LOOPS SHOW UPPER LOW IN OK FINALLY LIFTING TO THE
NORTHEAST ALL THE WHILE WEAKENING INTO AN OPEN WAVE. DECENT AREA
OF RAIN IN SOUTHERN MO WILL CONTINUE TO PUSH NORTH INTO OUR SOUTHERN
CWA LATE TONIGHT...SPREADING NORTHWARD OVER ALL THE CWA DURING
THURSDAY. FORECAST SOUNDINGS INDICATE DEEP MOISTURE IN PLACE ON
THURSDAY WITH PRECIPITABLE WATER NEARING 2 INCHES. OPERATIONAL
MODELS CONSISTENT ON BRINGING THE HIGHEST QPF ACROSS THE DVN CWA SO
SHOULD BE A RATHER WIDESPREAD 1/4-1/2 INCH OF RAIN WITH LOCALLY
HIGHER AMOUNTS AROUND AN INCH. MANY LOCATIONS IN THE DVN CWA HAVENT
SEEN MUCH RAIN SINCE AUGUST 5TH SO A DRINK OF WATER WOULDNT HURT.
VISIBLE SATELLITE SHOWS THICK CLOUD COVER ACROSS MUCH OF MO AND AR
WITH CURRENT TEMPERATURES STILL ONLY IN THE UPPER 60S AT SOME
OBSERVATION SITES IN THE OZARKS. WITH THIS IN MIND WE HAVE LOWERED
MAXIMUM TEMPERATURES ON THURSDAY KEEPING MUCH OF THE CWA IN THE
LOWER TO MID 70S. WITH CLOUDS INCREASING OVERNIGHT MINIMUM
TEMPERATURES BY THURSDAY MORNING SHOULD BE WARMER THAN THE PAST FEW
NIGHTS...IN THE 60S WHICH THE SURFACE PARCEL TRAJECTORY METHOD
CONFIRMS. THE CLOUD COVER SHOULD ALSO PRECLUDE ANY FOG
DEVELOPMENT.

WILL HAVE SHOWERS LIKELY ON THURSDAY BUT CONFINE MENTION OF ISOLATED
THUNDER TO THURSDAY AFTERNOON AS OPERATIONAL MODELS INDICATE ONLY
MARGINAL INSTABILITY IN PLACE DUE TO THICK CLOUD COVER.

..HAASE..

.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
LOTS OF CLOUDS AND PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY...THEN CLEARING AND COMFORTABLY MILD INTO WEDNESDAY.

TYPICAL LATE SUMMER WEATHER WITH HINT OF FALL BY SUNDAY NIGHT. USED
BLEND OF GFS AND HI-RES ECMWF WITH FAIR MODEL INITIALIZATION TODAY...
MAIN QUESTION IS WHAT TS FAY DOES NEXT 48-72 HOURS.

THURSDAY NIGHT...UPPED MINS WITH LOTS OF CLOUDS AND SHOWERS WITH SOME
LOWS NEAR 70F POSSIBLE FOR LATER SHIFTS TO CONSIDER.  UPPED POPS IN
EVENING WITH AREAS OF RAIN AND RAIN SHOWERS WITH ISOLATED THUNDER
POSSIBLE AS MAIN UPPER VORT MAX PASSES OVERHEAD.  SOME LINGERING
SHOWERS OVERNIGHT WITH NEARLY SATURATED LOW TO MID LEVELS TO
PRECLUDE ANY THUNDER INTO FRIDAY MORNING.  RAIN AMOUNTS LIGHT TO
MODERATE...GENERALLY BELOW A QUARTER INCH.

FRIDAY AND SATURDAY...KEPT CHANCE POPS WITH LINGERING SHOWER AND PM
AND EVENING THUNDERSTORM ACTIVITY AS MOISTURE POOLS AHEAD OF NEXT
FRONT.  AS OFTEN HAPPENS IN LATE FALL...EACH RUN TENDING THIS FRONT
TO BE SLIGHTLY STRONGER AND COOLER AS NEGATIVE FEEDBACK AS SUN
HEADS SOUTH AT 22+ MILES PER DAY AS HEAD TO EQUINOX.  MINOR CHANGES
TO TEMPERATURES WITH MINS FRIDAY NIGHT POSSIBLE A FEW DEGREES TOO
COOL AS MOISTURE AND CLOUDS POOL AHEAD OF FRONT. MAIN ISSUE IS PM
POPS AS FRONT ARRIVES AND LIKELY POPS WILL BE NEEDED FOR LATER SHIFTS
TO CONSIDER WITH TREND OF STRONGER FORCING AND MARGINAL LOWER END
SEVERE THAT SHOULD BE CLARIFIED NEXT 24 HOURS.  KEPT LIGHT TO
MODERATE RAIN AMOUNTS BUT SOME LOCALLY HIGHER AMOUNTS SUGGESTED
WITH STRONGER CONVECTION/FORCING.

SATURDAY NIGHT...CONTINUED SOME RISK OF MARGINAL SEVERE SUGGEST INTO
MID EVENING AS FRONT PASSES AS FRONT MOVES SOUTH WITH COOLER AND
DRIER AIR INTO ALL AREA BY DAYBREAK. MIN TEMPERATURES NW 1/2 MAY
NEED LOWERING A FEW MORE DEGREES FOR LATER SHIFTS TO REASSESS.

SUNDAY THROUGH WEDNESDAY...BEAUTIFUL LATE SUMMER WEATHER WITH
CANADIAN SURFACE HIGH PRESSURE TO KEEP TEMPERATURES SLIGHTLY BELOW
BELOW NORMAL.  LOW LEVEL THERMAL FIELDS SUGGEST MIN TEMPERATURES
PROBABLY 3 TO 5 DEGREES TOO MILD WITH SOME UPPER 40S FOR MONDAY AND
TUESDAY AM.  HIGHS ALSO MAY BE A DEGREE OR TWO TOO MILD.  DEWPOINTS
WITH STRONGER HIGH AND SUBSIDENCE MAY NEED LOWERING TO 40S AND
LOWER 50S FOR VERY COMFORTABLE CONDITIONS.   ..NICHOLS..

&&

.AVIATION...
SCT040-050 REMAINDER OF THIS AFTERNOON INTO EVENING. MID AND HIGH
LEVEL CLOUDS ABOVE 8000 FEET AGL WILL BE SPREADING NORTHWARD ACROSS
THE TAF SITES TONIGHT. SHOWERS WILL ALSO SPREAD NORTHWARD ACROSS THE
TAF SITES REACHING KBRL LATE TONIGHT AND KDBQ LATER THURSDAY
MORNING. CIGS/VIS WILL BE LOWERING ON THURSDAY TO MVFR CONDITIONS.
EXPECT OCNL IFR CONDITIONS IN HEAVIER SHOWERS SPREADING FROM SOUTH
TO NORTH.

..HAASE..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

$$

HAASE/NICHOLS

000
FXUS63 KDVN 201738 AAA
AFDDVN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1238 PM CDT WED AUG 20 2008

.UPDATE...
VISIBLE SATELLITE/SURFACE OBSERVATIONS INDICATE AREAS OF FOG HAVE
DISSIPATED. OTHERWISE PARTLY TO MOSTLY SUNNY SKIES EXPECTED
REMAINDER OF THE AFTERNOON. ALREADY HAVE SENT UPDATED GRIDS/ZFP
TO LOWER MAXIMUM TEMPERATURES A COUPLE OF DEGREES DUE TO FOG
LINGERING INTO THE MID MORNING.

MID AND HIGH LEVEL CLOUDS WILL SPREAD NORTHWARD AHEAD OF STORM
SYSTEM IN THE SOUTHERN PLAINS LATER TODAY AND TONIGHT. RAIN IN THE
LOWER MISSISSIPPI VALLEY HAS SPREAD INTO SOUTHERN MO WITH
TEMPERATURES CURRENTLY ONLY IN THE UPPER 60S IN NORTHERN AR AND
SOUTHERN MO. WILL BE LOWERING TEMPS ON THURSDAY BY AT LEAST SEVERAL
DEGREES AND RAISING POPS AS OPERATIONAL MODELS SPREAD RAIN FROM
SOUTH TO NORTH OVER THE DVN CWA LATE TONIGHT AND THURSDAY.

&&

.AVIATION...
SCT040-050 THIS AFTERNOON INTO EVENING. MID AND HIGH LEVEL CLOUDS
ABOVE 8000 FEET AGL WILL BE SPREADING NORTHWARD ACROSS THE TAF SITES
TONIGHT. SHOWERS WILL SPREAD NORTHWARD ACROSS THE TAF SITES REACHING
KBRL LATE TONIGHT AND KDBQ LATER THURSDAY MORNING. CIGS/VIS WILL BE
LOWERING ON THURSDAY TO MVFR/IFR SPREADING FROM SOUTH TO NORTH.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

HAASE

000
FXUS63 KDMX 201724 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1224 PM CDT WED AUG 20 2008

...UPDATED AVIATION SECTION...

.SHORT TERM...TODAY
MAIN CONCERN THIS MORNING WAS WHETHER TO INTRODUCE LOW POPS LATER
THIS AFTERNOON AS PERSISTENT SRN PLAINS LOW FINALLY APPROACHES IA.
NONE OF THE MODELS DEPICT MUCH IN THE WAY OF FORCING...BUT THEY DO
GRADUALLY TRY TO INCREASE DEEPER MOISTURE.  12Z ECMWF AND 21Z SREF
WERE MORE BULLISH IN THIS REGARD THAN GFS/NAM...BUT RESPECTIVE 00Z
AND 03Z RUNS HAVE BACKPEDALED SO WILL LEAVE DRY FOR THE TIME BEING
BUT INCREASE CLOUD WORDING.

IN MOST INSTANCES SOMETHING CLOSE TO PERSISTENCE WILL BE FOLLOWED
FOR HIGHS...INCLUDING ATYPICAL WARMER ALO.  INITIAL FEELING WAS THAT
OB MAY BE INCORRECT...BUT OTHER VICINITY MESONET OBS WERE SIMILAR
YESTERDAY SO WILL CONTINUE TO INCLUDE THAT TREND IN THE FORECAST.
ONLY EXCEPTION TO PERSISTENCE WAS SRN PORTIONS WHICH ARE SEVERAL
DEGREES COOLER.  LOWERING AND THICKENING CLOUDS...AND POTENTIALLY
SOME VIRGA...MAY HOLD THE WARMING DOWN THERE SOMEWHAT.  FARTHER
NORTH...EXPANDING NWD MOVING CLOUD SHIELD WILL HAVE TO BE WATCHED
BUT FORECAST SOUNDINGS STILL INDICATED DECENT MIXED IN DRIER LOW
LEVELS.

.LONG TERM...TONIGHT THROUGH TUE
THE FORECAST IS A BIT MORE COMPLICATED TODAY THAN IT HAS BEEN OVER
THE PAST COUPLE DAYS.  SURFACE HIGH PRESSURE IS NOW SLIDING EAST AS
PER FORECAST AND ALLOWING A LOW PRESSURE SYSTEMTO MOVE INTO CENTRAL
IOWA.  IN ADDITION...THERE IS A PRETTY GOOD SLUG OF MOISTURE
MISSOURI AN ARKANSAS THAT IS MOVING TO THE NORTH.  SOME SHOWERS WERE
NOTED WITH THIS OVERNIGHT IN FAR SOUTHERN MISSOURI. THIS FEATURE IS
MAINLY ASSOCIATED WITH THE MEANDERING UPPER LEVEL LOW THAT DRIFTED
IN FROM THE WESTERN HIGH PLAINS.  MOISTURE TRANSPORT VECTORS BRING
THIS INTO ABOUT THE SOUTHERN HALF OF IOWA LATE TONIGHT.  CAPE VALUES
ARE LOW AND SHEAR IS WEAK SO I AM EXPECTING MAINLY SHOWERS WITH AN
ISOLATED THUNDERSTORM NOT BEING RULED OUT.

A MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL PUSH OUT OF CANADA LATE
THURSDAY AND THIS WILL PUSH THE AFOREMENTIONED SURFACE LOW PRESSURE
SYSTEM OVER THE NORTHERN ROCKIES TO MOVE EAST... DRAGGING A COLD
FRONT ALONG WITH IT.  THE FRONT IS PROGGED TO MOVE ACROSS THE
FORECAST AREA FRIDAY NIGHT.  MODELS ARE INDICATING A NARROW RIBBON
OF 2500+ J/KG OF CAPE MAINLY ALONG THE FRONTAL BOUNDARY AND WHILE
SHEAR IS WEAK TO MODERATE IT MAY BE ENOUGH FOR ORGANIZED CONVECTION
TO DEVELOP WITH A FEW STRONGER STORMS FRIDAY EVENING/NIGHT.  THERE
IS SOME POTENTIAL FOR AN ISOLATED SEVERE STORM AT LEAST SO THE HWO
WILL BE UPDATED TO REFLECT A MINIMAL THREAT OR POTENTIAL FOR
ISOLATED SEVERE STORMS FRIDAY NIGHT.  THIS WOULD NOT BE ANYTHING
WIDESPREAD BUT THE STRENGTH OF THIS SYSTEM AND THE FRONTAL BOUNDARY
IS THE BEST WE`VE SEEN IN A THE LAST WEEK OR SO.  I FELT IT DESERVED
MENTION.  AFTER FROPA MID DAY SATURDAY...THE REST OF THE WEEKEND
LOOKS RATHER NICE WITH SEASONAL TEMPS.

AS FOR TEMPS...DROPPED TEMPS A DEGREE OR TWO FROM THE GOING FORECAST
FOR THURSDAY GIVEN THE CLOUD COVER AND DECENT PRECIP CHANCE.  TEMPS
ON FRIDAY SHOULD REBOUND AHEAD OF THE FRONT AS A PRETTY GOOD RETURN
FLOW DEVELOPS OVER CENTRAL IOWA.  THERE IS SOME CONCERN THAT THE
ATMOSPHERE WILL BE CAPPED DURING THE DAY AND INTO THE EVENING SO
CONVECTION MAY HAVE TO WAIT UNTIL THE FRONT PASSES.  THIS WOULD MEAN
THAT POPS ARE OVERDONE FOR DURING THE DAY FRIDAY BUT IT ALSO LENDS
CREDENCE TO A BETTER POTENTIAL FOR A FEW SEVERE STORMS AS THE
AIRMASS OVER IOWA BECOMES INCREASINGLY UNSTABLE DURING THE DAY.
IT`LL BE INTERESTING TO SEE HOW THIS DEVELOPS.  NO CHANGES WERE MADE
BEYOND DAY 5 AT THIS TIME.

&&

.AVIATION...20/18Z
VFR CONDITIONS WILL PREVAIL FOR MOST OF THE NEXT 24 HOURS. CLOUD
COVER WILL MOVE IN FROM THE SOUTH THIS EVENING AND OVERNIGHT...BUT
PREVAILING CIGS XPCTD TO REMAIN VFR. SOME SHOWERS ARE POSSIBLE THURS
MORNING MAINLY AT KDSM AND KOTM...BUT THESE SHOULD BE INTERMITTENT
WITH VSBYS REDUCED ONLY TO MVFR. THERE IS ALSO A POSSIBILITY OF
EARLY MORNING BR ONCE AGAIN...ESPECIALLY AT THE THREE NORTHERN
SITES...ALTHOUGH WITH HIGH CLOUD COVER RADIATIONAL COOLING MAY BE
INHIBITED SO CONFIDENCE IN BR IS SOMEWHAT LOWER THAN IT WAS YSTDY.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...BSS
LONG TERM...FAB
AVIATION...LEE

000
FXUS63 KDMX 201148
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
648 AM CDT WED AUG 20 2008

.SHORT TERM...TODAY
MAIN CONCERN THIS MORNING WAS WHETHER TO INTRODUCE LOW POPS LATER
THIS AFTERNOON AS PERSISTENT SRN PLAINS LOW FINALLY APPROACHES IA.
NONE OF THE MODELS DEPICT MUCH IN THE WAY OF FORCING...BUT THEY DO
GRADUALLY TRY TO INCREASE DEEPER MOISTURE.  12Z ECMWF AND 21Z SREF
WERE MORE BULLISH IN THIS REGARD THAN GFS/NAM...BUT RESPECTIVE 00Z
AND 03Z RUNS HAVE BACKPEDALED SO WILL LEAVE DRY FOR THE TIME BEING
BUT INCREASE CLOUD WORDING.

IN MOST INSTANCES SOMETHING CLOSE TO PERSISTENCE WILL BE FOLLOWED
FOR HIGHS...INCLUDING ATYPICAL WARMER ALO.  INITIAL FEELING WAS THAT
OB MAY BE INCORRECT...BUT OTHER VICINITY MESONET OBS WERE SIMILAR
YESTERDAY SO WILL CONTINUE TO INCLUDE THAT TREND IN THE FORECAST.
ONLY EXCEPTION TO PERSISTENCE WAS SRN PORTIONS WHICH ARE SEVERAL
DEGREES COOLER.  LOWERING AND THICKENING CLOUDS...AND POTENTIALLY
SOME VIRGA...MAY HOLD THE WARMING DOWN THERE SOMEWHAT.  FARTHER
NORTH...EXPANDING NWD MOVING CLOUD SHIELD WILL HAVE TO BE WATCHED
BUT FORECAST SOUNDINGS STILL INDICATED DECENT MIXED IN DRIER LOW
LEVELS.

.LONG TERM...TONIGHT THROUGH TUE
THE FORECAST IS A BIT MORE COMPLICATED TODAY THAN IT HAS BEEN OVER
THE PAST COUPLE DAYS.  SURFACE HIGH PRESSURE IS NOW SLIDING EAST AS
PER FORECAST AND ALLOWING A LOW PRESSURE SYSTEMTO MOVE INTO CENTRAL
IOWA.  IN ADDITION...THERE IS A PRETTY GOOD SLUG OF MOISTURE
MISSOURI AN ARKANSAS THAT IS MOVING TO THE NORTH.  SOME SHOWERS WERE
NOTED WITH THIS OVERNIGHT IN FAR SOUTHERN MISSOURI. THIS FEATURE IS
MAINLY ASSOCIATED WITH THE MEANDERING UPPER LEVEL LOW THAT DRIFTED
IN FROM THE WESTERN HIGH PLAINS.  MOISTURE TRANSPORT VECTORS BRING
THIS INTO ABOUT THE SOUTHERN HALF OF IOWA LATE TONIGHT.  CAPE VALUES
ARE LOW AND SHEAR IS WEAK SO I AM EXPECTING MAINLY SHOWERS WITH AN
ISOLATED THUNDERSTORM NOT BEING RULED OUT.

A MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL PUSH OUT OF CANADA LATE
THURSDAY AND THIS WILL PUSH THE AFOREMENTIONED SURFACE LOW PRESSURE
SYSTEM OVER THE NORTHERN ROCKIES TO MOVE EAST... DRAGGING A COLD
FRONT ALONG WITH IT.  THE FRONT IS PROGGED TO MOVE ACROSS THE
FORECAST AREA FRIDAY NIGHT.  MODELS ARE INDICATING A NARROW RIBBON
OF 2500+ J/KG OF CAPE MAINLY ALONG THE FRONTAL BOUNDARY AND WHILE
SHEAR IS WEAK TO MODERATE IT MAY BE ENOUGH FOR ORGANIZED CONVECTION
TO DEVELOP WITH A FEW STRONGER STORMS FRIDAY EVENING/NIGHT.  THERE
IS SOME POTENTIAL FOR AN ISOLATED SEVERE STORM AT LEAST SO THE HWO
WILL BE UPDATED TO REFLECT A MINIMAL THREAT OR POTENTIAL FOR
ISOLATED SEVERE STORMS FRIDAY NIGHT.  THIS WOULD NOT BE ANYTHING
WIDESPREAD BUT THE STRENGTH OF THIS SYSTEM AND THE FRONTAL BOUNDARY
IS THE BEST WE`VE SEEN IN A THE LAST WEEK OR SO.  I FELT IT DESERVED
MENTION.  AFTER FROPA MID DAY SATURDAY...THE REST OF THE WEEKEND
LOOKS RATHER NICE WITH SEASONAL TEMPS.

AS FOR TEMPS...DROPPED TEMPS A DEGREE OR TWO FROM THE GOING FORECAST
FOR THURSDAY GIVEN THE CLOUD COVER AND DECENT PRECIP CHANCE.  TEMPS
ON FRIDAY SHOULD REBOUND AHEAD OF THE FRONT AS A PRETTY GOOD RETURN
FLOW DEVELOPS OVER CENTRAL IOWA.  THERE IS SOME CONCERN THAT THE
ATMOSPHERE WILL BE CAPPED DURING THE DAY AND INTO THE EVENING SO
CONVECTION MAY HAVE TO WAIT UNTIL THE FRONT PASSES.  THIS WOULD MEAN
THAT POPS ARE OVERDONE FOR DURING THE DAY FRIDAY BUT IT ALSO LENDS
CREDENCE TO A BETTER POTENTIAL FOR A FEW SEVERE STORMS AS THE
AIRMASS OVER IOWA BECOMES INCREASINGLY UNSTABLE DURING THE DAY.
IT`LL BE INTERESTING TO SEE HOW THIS DEVELOPS.  NO CHANGES WERE MADE
BEYOND DAY 5 AT THIS TIME.

&&

.AVIATION...20/12Z
INITIAL CONCERN IS TRENDS OF ANYWHERE FROM MVFR TO LIFR FOG/STRATUS
EARLY THIS MORNING.  DSM SHOULD REMAIN VFR WHILE MVFR VSBYS AT
FOD/OTM SHOULD IMPROVE BY 15Z.  TRENDS AT MCW/ALO ARE MORE
PROBLEMATIC.  VIS/FOG SATELLITE IMAGERY SHOWS SWATCH OF IFR OR LOWER
STRATUS ALONG AND EAST OF MCW/VTI/CID LINE WITH HOLE NEAR ALO.
CONDITIONS SHOULD CHANGE LITTLE UNTIL AT LEAST 15Z AT MCW...BUT
SATELLITE TRENDS SHOW STRATUS APPROACHING ALO SO HAVE BROUGHT THESE
CONDITIONS INTO THAT SITE.

EXPECT VFR BUT WITH AT LEAST BKN MID/HIGH CLOUDS LATER TODAY.  LOW
PRESSURE APPROACHING FROM THE SOUTH WILL LOWER VFR CIGS OVERNIGHT
WITH LIGHT SHOWERS POSSIBLE AT DSM/OTM 09-12Z.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM/AVIATION...BSS
LONG TERM...FAB

000
FXUS63 KDMX 200930
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
425 AM CDT WED AUG 20 2008

.DISCUSSION...
THE FORECAST IS A BIT MORE COMPLICATED TODAY THAN IT HAS BEEN OVER
THE PAST COUPLE DAYS.  SURFACE HIGH PRESSURE IS NOW SLIDING EAST AS
PER FORECAST AND ALLOWING A LOW PRESSURE SYSTEM OVER THE ROCKIES TO
MOVE INTO CENTRAL IOWA.  IN ADDITION...THERE IS A PRETTY GOOD SLUG
OF MOISTURE MISSOURI AN ARKANSAS THAT IS MOVING TO THE NORTH.  SOME
SHOWERS WERE NOTED WITH THIS OVERNIGHT IN FAR SOUTHERN MISSOURI.
THIS FEATURE IS MAINLY ASSOCIATED WITH THE MEANDERING UPPER LEVEL
LOW THAT DRIFTED IN FROM THE WESTERN HIGH PLAINS.  MOISTURE
TRANSPORT VECTORS BRING THIS INTO ABOUT THE SOUTHERN HALF OF IOWA
LATE TONIGHT.  CAPE VALUES ARE LOW AND SHEAR IS WEAK SO I AM
EXPECTING MAINLY SHOWERS WITH AN ISOLATED THUNDERSTORM NOT BEING
RULED OUT.  A MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL PUSH OUT OF
CANADA LATE THURSDAY AND THIS WILL PUSH THE AFOREMENTIONED SURFACE
LOW PRESSURE SYSTEM OVER THE NORTHERN ROCKIES TO MOVE EAST...
DRAGGING A COLD FRONT ALONG WITH IT.  THE FRONT IS PROGGED TO MOVE
ACROSS THE FORECAST AREA FRIDAY NIGHT.  MODELS ARE INDICATING A
NARROW RIBBON OF 2500+ J/KG OF CAPE MAINLY ALONG THE FRONTAL
BOUNDARY AND WHILE SHEAR IS WEAK TO MODERATE IT MAY BE ENOUGH FOR
ORGANIZED CONVECTION TO DEVELOP WITH A FEW STRONGER STORMS FRIDAY
EVENING/NIGHT.  THERE IS SOME POTENTIAL FOR AN ISOLATED SEVERE STORM
AT LEAST SO THE HWO WILL BE UPDATED TO REFLECT A MINIMAL THREAT OR
POTENTIAL FOR ISOLATED SEVERE STORMS FRIDAY NIGHT.  THIS WOULD NOT
BE ANYTHING WIDESPREAD BUT THE STRENGTH OF THIS SYSTEM AND THE
FRONTAL BOUNDARY IS THE BEST WE`VE SEEN IN A THE LAST WEEK OR SO.  I
FELT IT DESERVED MENTION.  AFTER FROPA MID DAY SATURDAY...THE REST
OF THE WEEKEND LOOKS RATHER NICE WITH SEASONAL TEMPS.

AS FOR TEMPS...DROPPED TEMPS A DEGREE OR TWO FROM THE GOING FORECAST
FOR THURSDAY GIVEN THE CLOUD COVER AND DECENT PRECIP CHANCE.  TEMPS
ON FRIDAY SHOULD REBOUND AHEAD OF THE FRONT AS A PRETTY GOOD RETURN
FLOW DEVELOPS OVER CENTRAL IOWA.  THERE IS SOME CONCERN THAT THE
ATMOSPHERE WILL BE CAPPED DURING THE DAY AND INTO THE EVENING SO
CONVECTION MAY HAVE TO WAIT UNTIL THE FRONT PASSES.  THIS WOULD MEAN
THAT POPS ARE OVERDONE FOR DURING THE DAY FRIDAY BUT IT ALSO LENDS
CREDENCE TO A BETTER POTENTIAL FOR A FEW SEVERE STORMS AS THE
AIRMASS OVER IOWA BECOMES INCREASINGLY UNSTABLE DURING THE DAY.
IT`LL BE INTERESTING TO SEE HOW THIS DEVELOPS.  NO CHANGES WERE MADE
BEYOND DAY 5 AT THIS TIME.

&&

.AVIATION...20/06Z
VFR CEILINGS EXPECTED FOR MOST OF THE NEXT 24 HOURS...HOWEVER
VISIBILITY WILL BE A DIFFERENT STORY OVER NORTHERN TAF SITES. MAY
SEE IFR BRIEFLY BETWEEN 9-12 Z ESPECIALLY AT KFOD WITH DEW POINT
DEPRESSIONS ALREADY IN THE 2-3 DEGREE RANGE. THROUGH THE HIGHWAY 30
CORRIDOR. SURFACE WINDS WILL BE LIGHT THROUGHOUT THE FORECAST.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SMALL
LONG TERM...FAB
AVIATION...RUSSELL

000
FXUS63 KDVN 200801
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 AM CDT WED AUG 20 2008

.SYNOPSIS...
00Z SUBJECTIVE UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY SHOW CUT-OFF
LOW OVER NORTH TX. LARGE SWATH OF PCPN IS ADVANCING NORTHWARD
THROUGH THE LOWER MISSISSIPPI VALLEY WITHIN SUBTROPICAL MOIST PLUME
WRAPPING IN AROUND EASTERN SIDE OF SYSTEM. LEADING EDGE OF THE
PCPN WAS NEAR THE MO/AR BORDER. ANOMALOUSLY DEEP SHORTWAVE TROUGH
WAS LOCATED OFF THE BRITISH COLUMBIA COAST WITH ENERGY SHIFTING EAST
INTO NORTHERN ROCKIES IN ADVANCE OF SYSTEM. MEANWHILE... TROPICAL
STORM FAY WAS LIFTING NORTH ALONG EAST COAST OF CENTRAL FL WITH THE
CENTER PASSING NEAR MELBOURNE ATTM. CLOSER TO HOME... SFC HIGH
WAS ANCHORED OVER THE GREAT LAKES WITH LIGHT EASTERLY FLOW FUNNELING
INTO CWA AROUND PERIPHERY. WEAK BOUNDARY ANALYZED JUST SOUTHWEST
OF KCID-KMLI LINE... DENOTED MORE BY SUBTLE WIND SHIFT AND WEAK LLVL
CONVERGENCE WITH WINDS MORE FROM NORTHEAST BEHIND BOUNDARY WHILE FROM
EAST/SOUTHEAST IN ADVANCE. FOG FOUND YET AGAIN THIS MORNING...MORE
WIDESPREAD THOUGH WITH MOISTURE POOLING ALONG WEAK BOUNDARY...AND LIGHT
WINDS AND MAINLY CLEAR SKIES WITH NOCTURNAL SC/AC DEVELOPMENT IN PATCHES.
..05..

&&

.SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGE IS PCPN CHCS AND TEMPS. SHORT TERM MODELS IN DECENT
AGREEMENT ON TX CUT-OFF LOW FINALLY OPENING UP AND BEGINNING TO
LIFT GRADUALLY NORTH IN ADVANCE OF SHORTWAVE TROUGH DIGGING INTO THE
PACIFIC NORTHWEST. SUBTROPICAL MOIST PLUME ADVANCING NORTHWARD WILL
BRING INCREASE IN MID/HIGH LEVEL MOISTURE TODAY... BUT EASTERLY LLVL
FLOW SHOULD KEEP DEEPER MOISTURE AND PCPN THREAT SOUTH OF THE
CWA TODAY. SOME SUGGESTION OF WEAK BOUNDARY /LOW LEVEL CONVERGENCE/
LINGERING OVER AREA TODAY AND WITH HEATING CAN/T TOTALLY RULE OUT
VERY ISOLD WEAK CONVECTION IF CONVECTIVE TEMPS REACHED (82-85 DEGS)
MAINLY ALONG/EAST OF KCID-KMLI LINE... THOUGH FCST SOUNDINGS DEPICT
DECENT MID LEVEL CAP TOUGH TO OVERCOME. GIVEN THIS HAVE LEFT OUT
MENTION. IF WEAK CONVECTION DEVELOPS... WOULD BE SHORT-LIVED AND
VERY ISOLD GIVEN WEAK VERTICAL PROFILES... SIMILAR TO WHAT WAS OBSERVED
YESTERDAY... AND NOT WORTH MENTION. PERSISTENCE TEMPS HAVE
WORKED VERY WELL PAST SEVERAL DAYS... AND SEE NO REASON TO DEVIATE...
THOUGH WENT A LITTLE LOWER TODAY ESPECIALLY IN THE SOUTH WHERE MORE
SUBSTANTIAL INCREASE IN MID/HIGH CLOUDINESS EXPECTED.
TONIGHT...CUT-OFF LOW BEGINS LIFTING NORTH WHILE WEAKENING. MODELS
SUGGEST RECYCLING OF DRIER AIR INTO THE EAST WITH LOW LEVEL
EASTERLY FLOW AROUND SFC HIGH PRESSURE RIDGE SAGGING SOUTH INTO THE
OHIO VALLEY. MEANWHILE... MOISTURE WILL DEEPEN ALONG AND ESPECIALLY WEST
OF THE MISSISSIPPI WITH SUBTROPICAL PLUME CONTINUING TO ADVANCE
NORTHWARD. WEAK SFC WAVE AND LOW LEVEL CYCLONIC FLOW ATTENDANT TO
CUT-OFF LOW TO LIFT NORTH TO I-70 CORRIDOR BY 12Z. ISENTROPIC LIFT
SHOULD LEAD TO TOP DOWN SATURATION WITH PCPN CHCS INCREASING BY LATE
EVE FAR SOUTH... AND ADVANCING TO JUST SOUTH OF KCID-KMLI LINE OVERNIGHT.
HAVE NUDGED UP POPS ESPECIALLY AFT 06Z ALONG AND WEST OF THE MISSISSIPPI
RIVER AND SOUTH OF I-80. POPS MAY STILL BE TOO LOW IN THE FAR SOUTH/WEST
AND PASS ON CONCERNS TO DAY CREW. VERY LITTLE IN WAY OF THUNDER OBSERVED
WITH PCPN SHIELD LIFTING THROUGH AR EARLY THIS MORNING... AND FCST
SOUNDINGS FAIRLY SATURATED WITH WEAK MID LEVEL LAPSE RATES... THUS PCPN
MOSTLY JUST SHOWERS. CLOUDS TO RESULT IN WARMER MIN TEMPS MOST AREAS...
WITH WIDESPREAD 60S.    ..05..

.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
THURSDAY THROUGH FRIDAY NIGHT...THE DETAILS OF THE MODELS DIFFER BUT
THE INTERNAL SIGNALS ARE SIMILAR. A SURGE OF MOISTURE WILL MOVE
NORTHWARD IN ASSOCIATION WITH THE PLAINS CLOSED LOW. PRECIP WILL
OVERSPREAD THE CWFA DURING THE DAY THURSDAY AND KEEP TEMPERATURES
BELOW NORMAL. LATER SHIFTS WILL NEED TO ASSESS IF POPS NEED TO BE
RAISED FURTHER OR MAX TEMPS LOWERED. PASSAGE OF UPPER LOW THURSDAY
NIGHT MAY RESULT IN A BREAK IN THE PRECIP LATE THURSDAY NIGHT/FRIDAY
MORNING. SIGNAL IS NOT CLEAR SO WILL GO WITH SLIGHTLY LOWER POPS.
MIN TEMPS MAY NEED TO BE RAISED IF MID TEEN DEW POINTS AT 850MB ARE
REALIZED. THERE MAY ALSO BE A THREAT OF LOCALLY HEAVY RAINFALL
THURSDAY/THURSDAY EVENING. NEXT VORT MAX TO ARRIVE FRIDAY
AFTERNOON/EVENING WHICH SHOULD RESULT IN ANOTHER ROUND OF PRECIP.
HOWEVER...THE TRIGGER IS NOT OVERLY STRONG SO FRIDAY
AFTERNOON/EVENING MAY NOT SEE MUCH IN THE WAY OF PRECIP.

SATURDAY ON...DID NOT MAKE ANY CHANGES TO THE CURRENT FCST. MODELS
BRING A COLD FRONT THROUGH THE AREA ON SATURDAY WHICH SHOULD BRING
ANOTHER ROUND OF FAIRLY WIDESPREAD PRECIPITATION. GIVEN THE ALREADY
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE...THERE MAY BE A
POTENTIAL FOR LOCALLY HEAVY RAINFALL. MODERATELY STRONG HIGH
PRESSURE BUILDS IN SUNDAY THROUGH TUESDAY BRINGING DRY WX. MAX
TEMPERATURES MAY NEED TO BE LOWERED AS PLENTY OF LOW LEVEL EASTERLY
FLOW WILL BE PRESENT.          ..08..

&&

.AVIATION...
VFR CIGS GENERALLY EXPECTED THROUGH PERIOD... THOUGH FOG WILL BRING
PERIOD OF MVFR/IFR VSBYS THROUGH 14Z. OTHERWISE... LIGHT E/SE
WINDS. CUT-OFF LOW OVER TX TO WEAKEN AND LIFT SLOWLY NORTH.
MOISTURE PLUME SURGING NORTH TO BRING INCREASE IN MID/HIGH CLOUDS
TODAY INTO THIS EVE. MOISTURE DEEPENING SUFFICIENTLY TO BRING CHC
OF SHRA TO KBRL AFT 06Z... WITH SHOWERS POSSIBLY AS FAR NORTH AS
NEAR KCID AND KMLI TERMINALS BY 12Z THURS.     ..05..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$


05/08

000
FXUS63 KDMX 200437 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE DES MOINES IA
1135 PM CDT TUE AUG 19 2008

.DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE AREA TONIGHT RESULTING IN LIGHT AND
VARIABLE WINDS...GENERALLY SOUTHEAST TO SOUTH...AND FEW-SCT MID
LEVEL CLOUDS. ONLY SIGNIFICANT WEATHER IMPACT WILL BE POTENTIAL FOR
EARLY MORNING FOG. AT THIS TIME SUCH POTENTIAL SEEMS MITIGATED BY
PARTLY CLOUDY SKIES AND JUST A FEW KNOTS OF WIND...SO HAVE ONLY
INCLUDED PATCHY FOG NORTH OF THE I-80 CORRIDOR. ANY DENSE FOG SHOULD
BE VERY LOCALIZED...AND ONLY SIGNIFICANT IMPACTS WILL BE TO AVIATION
CONCERNS.  WED SHOULD BE SIMILAR TO TDA WITH TEMPS CLOSE OR PERHAPS
A DEG WARMER THAN HIGHS TUE.  CLOSED LOW THAT HAS WORKED ITS WAY
SOUTH THRU THE RCKYS IN TO THE SRN U.S. WILL FINALLY LIFT NWD INTO
THE CENTRAL CONUS.  MOISURE INCREASES WED NGT AND CONT INTO THU.
EXPECT TO SEE SIG COOLING ARND UPR LOW AND DROPPED TEMPS INTO THE
MID TO UPPER 70S FOR THU.  WOULD NOT BE SURPRISED TO SEE THEM
ACTUALLY TURN OUT ANOTHER 3-5 DEG COOLER...DEPENDING ON HOW THICK
THE CLOUDS ARE. UNSETTLED PERIOD FRI INTO SAT YET AS LOW PRES/WSHFT
LINE MOVS IN FM THE NW.  FRI WILL BE A TRICKY DAY AS THE EXITING SYS
FROM THU WILL HAVE SOME SEPARATION FROM THE APCHG SYS TO THE NW.
THIS MAY ALLOW TEMPS TO RECOVER FOR A WHILE FRI.  CDFNT PASSES FRI
NGT INTO SAT...THEN EXPECT TO SEE ANOTHER RELATIVELY DRY PD AS HI
PRES BLDS INTO THE UPPER MIDWEST.  THINKING ATTM IS THAT CONVECTION
AROUND THE EDGE OF THE HIGH WILL BE PUSHED TO THE SW OF THE CWA AND
HAVE PLAYED IT THAT WAY FOR THE FIRST PART OF NEXT WEEK.

&&

.AVIATION...20/06Z
VFR CIELINGS EXPECTED FOR MOST OF THE NEXT 24 HOURS...HOWEVER
VISIBILITY WILL BE A DIFFERENT STORY OVER NORTHERN TAF SITES. MAY
SEE IFR BRIEFLY BETWEEN 9-12 Z ESPECIALLY AT KFOD WITH DEW POINT
DEPRESSIONS ALREADY IN THE 2-3 DEGREE RANGE. THROUGH THE HIGHWAY 30
CORRIDOR. SURFACE WINDS WILL BE LIGHT THROUGHOPUT THE FORECAST.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LEE
LONG TERM...MS AUG 08
AVIATION...RUSSELL

000
FXUS63 KDMX 192254 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE DES MOINES IA
600 PM CDT TUE AUG 19 2008

.DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE AREA TONIGHT RESULTING IN LIGHT AND
VARIABLE WINDS...GENERALLY SOUTHEAST TO SOUTH...AND FEW-SCT MID
LEVEL CLOUDS. ONLY SIGNIFICANT WEATHER IMPACT WILL BE POTENTIAL FOR
EARLY MORNING FOG. AT THIS TIME SUCH POTENTIAL SEEMS MITIGATED BY
PARTLY CLOUDY SKIES AND JUST A FEW KNOTS OF WIND...SO HAVE ONLY
INCLUDED PATCHY FOG NORTH OF THE I-80 CORRIDOR. ANY DENSE FOG SHOULD
BE VERY LOCALIZED...AND ONLY SIGNIFICANT IMPACTS WILL BE TO AVIATION
CONCERNS.  WED SHOULD BE SIMILAR TO TDA WITH TEMPS CLOSE OR PERHAPS
A DEG WARMER THAN HIGHS TUE.  CLOSED LOW THAT HAS WORKED ITS WAY
SOUTH THRU THE RCKYS IN TO THE SRN U.S. WILL FINALLY LIFT NWD INTO
THE CENTRAL CONUS.  MOISURE INCREASES WED NGT AND CONT INTO THU.
EXPECT TO SEE SIG COOLING ARND UPR LOW AND DROPPED TEMPS INTO THE
MID TO UPPER 70S FOR THU.  WOULD NOT BE SURPRISED TO SEE THEM
ACTUALLY TURN OUT ANOTHER 3-5 DEG COOLER...DEPENDING ON HOW THICK
THE CLOUDS ARE. UNSETTLED PERIOD FRI INTO SAT YET AS LOW PRES/WSHFT
LINE MOVS IN FM THE NW.  FRI WILL BE A TRICKY DAY AS THE EXITING SYS
FROM THU WILL HAVE SOME SEPARATION FROM THE APCHG SYS TO THE NW.
THIS MAY ALLOW TEMPS TO RECOVER FOR A WHILE FRI.  CDFNT PASSES FRI
NGT INTO SAT...THEN EXPECT TO SEE ANOTHER RELATIVELY DRY PD AS HI
PRES BLDS INTO THE UPPER MIDWEST.  THINKING ATTM IS THAT CONVECTION
AROUND THE EDGE OF THE HIGH WILL BE PUSHED TO THE SW OF THE CWA AND
HAVE PLAYED IT THAT WAY FOR THE FIRST PART OF NEXT WEEK.

&&

.AVIATION...20/00Z
VFR CONDITIONS EXPECTED FOR MOST OF THE NEXT 24 HOURS. ONLY
EXCEPTION WILL BE EARLY MORNING FOG...WITH MVFR VSBYS MOST LIKELY
BETWEEN 08Z AND 13Z WED ESPECIALLY IN THE NORTH...AND BRIEF IFR
VSBYS POSSIBLE AROUND 11-12Z MAINLY AT KFOD AND KALO. OTHERWISE NO
PRECIP OR LOW CIGS ANTICIPATED THROUGH THE PERIOD.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LEE
LONG TERM...MS AUG 08
AVIATION...LEE/71

000
FXUS63 KDMX 192008 AAA
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
310 PM CDT TUE AUG 19 2008

.DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE AREA TONIGHT RESULTING IN LIGHT AND
VARIABLE WINDS...GENERALLY SOUTHEAST TO SOUTH...AND FEW-SCT MID
LEVEL CLOUDS. ONLY SIGNIFICANT WEATHER IMPACT WILL BE POTENTIAL FOR
EARLY MORNING FOG. AT THIS TIME SUCH POTENTIAL SEEMS MITIGATED BY
PARTLY CLOUDY SKIES AND JUST A FEW KNOTS OF WIND...SO HAVE ONLY
INCLUDED PATCHY FOG NORTH OF THE I-80 CORRIDOR. ANY DENSE FOG SHOULD
BE VERY LOCALIZED...AND ONLY SIGNIFICANT IMPACTS WILL BE TO AVIATION
CONCERNS.  WED SHOULD BE SIMILAR TO TDA WITH TEMPS CLOSE OR PERHAPS
A DEG WARMER THAN HIGHS TUE.  CLOSED LOW THAT HAS WORKED ITS WAY
SOUTH THRU THE RCKYS IN TO THE SRN U.S. WILL FINALLY LIFT NWD INTO
THE CENTRAL CONUS.  MOISURE INCREASES WED NGT AND CONT INTO THU.
EXPECT TO SEE SIG COOLING ARND UPR LOW AND DROPPED TEMPS INTO THE
MID TO UPPER 70S FOR THU.  WOULD NOT BE SURPRISED TO SEE THEM
ACTUALLY TURN OUT ANOTHER 3-5 DEG COOLER...DEPENDING ON HOW THICK
THE CLOUDS ARE. UNSETTLED PERIOD FRI INTO SAT YET AS LOW PRES/WSHFT
LINE MOVS IN FM THE NW.  FRI WILL BE A TRICKY DAY AS THE EXITING SYS
FROM THU WILL HAVE SOME SEPARATION FROM THE APCHG SYS TO THE NW.
THIS MAY ALLOW TEMPS TO RECOVER FOR A WHILE FRI.  CDFNT PASSES FRI
NGT INTO SAT...THEN EXPECT TO SEE ANOTHER RELATIVELY DRY PD AS HI
PRES BLDS INTO THE UPPER MIDWEST.  THINKING ATTM IS THAT CONVECTION
AROUND THE EDGE OF THE HIGH WILL BE PUSHED TO THE SW OF THE CWA AND
HAVE PLAYED IT THAT WAY FOR THE FIRST PART OF NEXT WEEK.

&&

.AVIATION...19/18Z
VFR CONDITIONS EXPECTED FOR MOST OF THE NEXT 24 HOURS. ONLY
EXCEPTION WILL BE EARLY MORNING FOG...WITH MVFR VSBYS MOST LIKELY
BETWEEN 08Z AND 13Z WED ESPECIALLY IN THE NORTH...AND BRIEF IFR
VSBYS POSSIBLE AROUND 11-12Z MAINLY AT KFOD AND KALO. OTHERWISE NO
PRECIP OR LOW CIGS ANTICIPATED THROUGH THE PERIOD.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LEE
LONG TERM...MS AUG 08
AVIATION...LEE

000
FXUS63 KDVN 192002
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
302 PM CDT TUE AUG 19 2008

.SYNOPSIS...
WEAK BACK DOOR COLD FRONT LOCATED ALONG I-80 IN ILLINOIS TO THE QUAD
CITIES TO EAST OF CID AND WILL WASH OUT OVERNIGHT. ISOLATED SHOWERS
EXPECTED REMAINDER THIS AFTERNOON INTO EARLY EVENING NEAR BOUNDARY.
OTHERWISE DEEP TROUGH IN THE PACIFIC NORTHWEST WILL BEGIN TO LIFT
STATIONARY LOW IN THE EASTERN TX PANHANDLE OVERNIGHT PER HENRY RULE
CIRCA 1978. SOUTHERN PLAINS LOW IS EXPECTED TO LIFT OUT AS AN OPEN
WAVE BRINGING A CHANCE OF SHOWERS OR STORMS LATER THIS WEEK. PASSAGE
OF MAIN TROUGH THIS WEEKEND WILL RETURN NORTHWEST FLOW ALOFT AND
SOMEWHAT COOLER AND LESS HUMID AIR WHICH SHOULD LAST INTO EARLY NEXT
WEEK.

..HAASE..

&&

.SHORT TERM...TONIGHT AND WEDNESDAY...
VISIBLE SATELLITE SHOWS WEAK BACK DOOR COLD FRONT ALONG I-80 IN
ILLINOIS TO NEAR THE QUAD CITIES TO EAST OF CID. ISOLATED SHOWERS
EXPECTED ALONG BOUNDARY WITH PEAK HEATING LATE AFTERNOON AND EARLY
EVENING. BUT WITH LIGHT LOWER AND MID LEVEL WINDS...WEAK SURFACE
CONVERGENCE AND LACK OF UPPER SUPPORT NOT EXPECTING THUNDERSTORMS.
BELIEVE COVERAGE OF LOW TOP SHOWERS CONFINED TO NEAR FRONTAL
BOUNDARY AND LESS THAN 15 PERCENT POPS SO WILL NOT MENTION SHOWERS
IN GRIDS/ZFP. DEWPOINTS HAVE SHOT UP INTO THE 60S IN MANY LOCATIONS
SO MINIMUM TEMPERATURES WEDNESDAY MORNING ABOVE 60.

ON WEDNESDAY A MORE TYPICAL MID AUGUST DAY EXPECTED WITH MAXIMUM
TEMPERATURES IN THE MID 80S...RATHER HUMID WITH DEWPOINTS IN THE
60S. SOME WISPY HIGH LEVEL CLOUDS SHOULD BEGIN TO SPREAD INTO
THE AREA FROM THE SOUTHWEST LATER IN THE DAY...AS THE SOUTHERN
PLAINS LOW APPROACHES.

..HAASE..

.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...
COMBINATION OF TX CUTOFF UPPER LOW LIFTING NORTHEAST INTO THE AREA
LATE IN THE WEEK...FOLLOWED BY UPPER TROUGH PASSAGE EARLY IN THE
WEEKEND TO RESULT IN SEVERAL DAYS OF ENHANCED RAIN CHANCES. FIRST
ROUND WILL BE WITH ELEVATED WARM ADVECTION THAT DEVELOPS INTO THE
SOUTH WED NIGHT. WITH UNIMPRESSIVE MID LEVEL LAPSE RATES...HAVE ONLY
ISOLATED THUNDERSTORMS MENTIONED. BETTER QG FORCING ARRIVES ON THU
AHEAD OF MODEL DEPICTED VORT EMBEDDED IN THE TROUGH AND HAVE HIGH
CHANCE POPS BY AFTERNOON WHEN MODELS DEVELOP SOME MODEST LOW LEVEL
CAPE. MAIN AXIS OF THIS WEAKENING WAVE SLIDES THROUGH FRI NIGHT INTO
EARLY SAT AS IT GETS PULLED INTO THE MAIN LONGER WAVE UPPER TROUGH
AND HAVE MAINTAINED RAIN AND THUNDERSTORM CHANCES THROUGHOUT. THESE
CAN LIKELY BE FURTHER REFINED WITH LATER MODEL RUNS. BOTH THE 12Z
GFS AND ECMWF DEPICT STRONGEST QG FORCING ON SAT AS BASE OF CANADIAN
UPPER TROUGH SWEEPS A COLD FRONT THROUGH THE AREA. THIS FROPA SHOULD
END THE RAIN CHANCES AS IT WILL BE FOLLOWED BY HIGH PRESSURE
SETTLING INTO THE UPPER MS VALLEY SUN AND MON. RIGHT NOW...MODELS
KEEP REMNANTS OF FAY MEANDERING WELL SOUTH OF THE AREA INTO NEXT
WEEK WITH MINIMAL IMPACT LOCALLY.

HIGHS KEPT IN THE 80S SUN THROUGH TUE...BUT THESE COULD BE
TOO WARM...DEPENDING ON THE STRENGTH OF THE HIGH TO THE NORTH AND
RESULTING LOW LEVEL E-NE FLOW THAT HAS RESULTED IN COOLER THAN
NORMAL TEMPS OVER THE PAST COUPLE WEEKS. BY TUE...MODELS START TO
SUPPRESS THE WESTERN RIDGE WITH ECMWF DEPICTING AN UPPER LOW
OVERHEAD BY TUE. RECENT TRENDS SUPPORT LOW CONFIDENCE IN
MODELS THAT FAR OUT AND THUS BROUGHT IN TUE WITH NEAR CLIMO
CONDITIONS. ..SHEETS..

&&

.AVIATION...
ISOLATED -SHRA IN EASTERN IA REMAINDER OF THIS AFTERNOON INTO EARLY
EVENING WITH PEAK HEATING. OTHERWISE PREVAILING VFR CONDITIONS WITH
FEW-SCT040-080 THROUGH WEDNESDAY...BUT LOCAL 4-6SM BR 10-14Z.

..HAASE..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

$$

HAASE/SHEETS

000
FXUS63 KDMX 191727 AAA
AFDDMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1227 PM CDT TUE AUG 19 2008

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...
HIGH PRESSURE WILL REMAIN IN CONTROL OVER CENTRAL IOWA THROUGH LATE
WEDNESDAY.  THE HIGH IS MOVING TO THE EAST AND AS IT DOES...RETURN
FLOW WILL INCREASE AND TEMPS SHOULD WARM ACCORDINGLY MID WEEK.  THE
PASSING OF THE HIGH WILL ALLOW A LOW PRESSURE SYSTEM OVER THE
CENTRAL/SOUTHERN HIGH PLAINS TO MEANDER INTO THE UPPER MIDWEST.
THIS WILL BRING AT LEAST SOME CHANCE FOR SHOWERS OR THUNDERSTORMS TO
CENTRAL IOWA ON THURSDAY.  A STRONGER SYSTEM WILL SWEEP ACROSS
SOUTHERN CANADA THURSDAY NIGHT AND FRIDAY AND THE AFOREMENTIONED
SYSTEM WILL BLEND WITH THIS SYSTEM STRENGTHENING THE ATTENDANT COLD
FRONT.  THE FRONT IS FORECAST TO PUSH TO THE EAST ACROSS CENTRAL
IOWA THURSDAY NIGHT THROUGH FRIDAY NIGHT.  FORCING IS NOT ALL THAT
IMPRESSIVE AT THIS TIME AND THE SHEAR IS WEAK BUT THERE DOES APPEAR
TO BE A NARROW RIBBON OF BETTER SHEAR MOVING ALONG THE FRONT LATE
FRIDAY INTO FRIDAY NIGHT.  THIS WOULD GIVE US OUR BEST SHOT AT
PRECIP AND THUNDERSTORMS..  MODELS HAVE BEEN FAIRLY CONSISTENT WITH
THIS FEATURE AND I HAVE MADE ADJUSTMENTS TO CLOUD COVER AND TEMPS
THIS FORECAST ALONG WITH SOME REFINEMENT TO PRECIP CHANCES AND
TIMING.  NO OTHER CHANGES MADE BEYOND SATURDAY.  AS FOR TEMPS...I
STAYED CLOSER TO MOS WITH THE TRENDS OF PERSISTENCE GIVEN THAT
WATERLOO AND MASON CITY HAVE BEEN WARMER THAN DES MOINES THE PAST
COUPLE DAYS.

&&

.AVIATION...19/18Z
VFR CONDITIONS EXPECTED FOR MOST OF THE NEXT 24 HOURS. ONLY
EXCEPTION WILL BE EARLY MORNING FOG...WITH MVFR VSBYS MOST LIKELY
BETWEEN 08Z AND 13Z WED ESPECIALLY IN THE NORTH...AND BRIEF IFR
VSBYS POSSIBLE AROUND 11-12Z MAINLY AT KFOD AND KALO. OTHERWISE NO
PRECIP OR LOW CIGS ANTICIPATED THROUGH THE PERIOD.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SMALL
LONG TERM...BOKSA
AVIATION...LEE

000
FXUS63 KDMX 191201
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
701 AM CDT TUE AUG 19 2008

.DISCUSSION...
HIGH PRESSURE WILL REMAIN IN CONTROL OVER CENTRAL IOWA THROUGH LATE
WEDNESDAY.  THE HIGH IS MOVING TO THE EAST AND AS IT DOES...RETURN
FLOW WILL INCREASE AND TEMPS SHOULD WARM ACCORDINGLY MID WEEK.  THE
PASSING OF THE HIGH WILL ALLOW A LOW PRESSURE SYSTEM OVER THE
CENTRAL/SOUTHERN HIGH PLAINS TO MEANDER INTO THE UPPER MIDWEST.
THIS WILL BRING AT LEAST SOME CHANCE FOR SHOWERS OR THUNDERSTORMS TO
CENTRAL IOWA ON THURSDAY.  A STRONGER SYSTEM WILL SWEEP ACROSS
SOUTHERN CANADA THURSDAY NIGHT AND FRIDAY AND THE AFOREMENTIONED
SYSTEM WILL BLEND WITH THIS SYSTEM STRENGTHENING THE ATTENDANT COLD
FRONT.  THE FRONT IS FORECAST TO PUSH TO THE EAST ACROSS CENTRAL
IOWA THURSDAY NIGHT THROUGH FRIDAY NIGHT.  FORCING IS NOT ALL THAT
IMPRESSIVE AT THIS TIME AND THE SHEAR IS WEAK BUT THERE DOES APPEAR
TO BE A NARROW RIBBON OF BETTER SHEAR MOVING ALONG THE FRONT LATE
FRIDAY INTO FRIDAY NIGHT.  THIS WOULD GIVE US OUR BEST SHOT AT
PRECIP AND THUNDERSTORMS..  MODELS HAVE BEEN FAIRLY CONSISTENT WITH
THIS FEATURE AND I HAVE MADE ADJUSTMENTS TO CLOUD COVER AND TEMPS
THIS FORECAST ALONG WITH SOME REFINEMENT TO PRECIP CHANCES AND
TIMING.  NO OTHER CHANGES MADE BEYOND SATURDAY.  AS FOR TEMPS...I
STAYED CLOSER TO MOS WITH THE TRENDS OF PERSISTENCE GIVEN THAT
WATERLOO AND MASON CITY HAVE BEEN WARMER THAN DES MOINES THE PAST
COUPLE DAYS.

&&

.AVIATION...19/12Z
VFR CONDITIONS THROUGH MUCH OF THE PERIOD WITH SCT MID CLOUDS IN AND
OUT.  ONLY MVFR POTENTIAL WOULD BE LINGERING FOG VERY EARLY THIS
MORNING...AND THEN REPEATING AGAIN EARLY WED MORNING.  SOME
POTENTIAL FOR IFR CONDITIONS AFT 09Z...BUT CONFIDENCE IS NOT GREAT
ENOUGH TO INCLUDE AT THIS TIME.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM/AVIATION...SMALL
LONG TERM...BOKSA

000
FXUS63 KDMX 190943
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
445 AM CDT TUE AUG 19 2008

.DISCUSSION...
HIGH PRESSURE WILL REMAIN IN CONTROL OVER CENTRAL IOWA THROUGH LATE
WEDNESDAY.  THE HIGH IS MOVING TO THE EAST AND AS IT DOES...RETURN
FLOW WILL INCREASE AND TEMPS SHOULD WARM ACCORDINGLY MID WEEK.  THE
PASSING OF THE HIGH WILL ALLOW A LOW PRESSURE SYSTEM OVER THE
CENTRAL/SOUTHERN HIGH PLAINS TO MEANDER INTO THE UPPER MIDWEST.
THIS WILL BRING AT LEAST SOME CHANCE FOR SHOWERS OR THUNDERSTORMS TO
CENTRAL IOWA ON THURSDAY.  A STRONGER SYSTEM WILL SWEEP ACROSS
SOUTHERN CANADA THURSDAY NIGHT AND FRIDAY AND THE AFOREMENTIONED
SYSTEM WILL BLEND WITH THIS SYSTEM STRENGTHENING THE ATTENDANT COLD
FRONT.  THE FRONT IS FORECAST TO PUSH TO THE EAST ACROSS CENTRAL
IOWA THURSDAY NIGHT THROUGH FRIDAY NIGHT.  FORCING IS NOT ALL THAT
IMPRESSIVE AT THIS TIME AND THE SHEAR IS WEAK BUT THERE DOES APPEAR
TO BE A NARROW RIBBON OF BETTER SHEAR MOVING ALONG THE FRONT LATE
FRIDAY INTO FRIDAY NIGHT.  THIS WOULD GIVE US OUR BEST SHOT AT
PRECIP AND THUNDERSTORMS..  MODELS HAVE BEEN FAIRLY CONSISTENT WITH
THIS FEATURE AND I HAVE MADE ADJUSTMENTS TO CLOUD COVER AND TEMPS
THIS FORECAST ALONG WITH SOME REFINEMENT TO PRECIP CHANCES AND
TIMING.  NO OTHER CHANGES MADE BEYOND SATURDAY.  AS FOR TEMPS...I
STAYED CLOSER TO MOS WITH THE TRENDS OF PERSISTENCE GIVEN THAT
WATERLOO AND MASON CITY HAVE BEEN WARMER THAN DES MOINES THE PAST
COUPLE DAYS.

&&

.AVIATION...19/06Z
KFOD HAS DEVELOPED IFR FOG AND MAY BE INTERMITTENT THROUGH THE
OVERNIGHT. MFVR FOG IS FORECAST BETWEEN 9-13 UTC...WHILE VFR
CEILINGS ARE FORECAST THROUGH THE REMAINDER OF TAF PERIOD...WITH
LIGHT VARIABLE WIND OVERNIGHT BECOMING SUSTAINED UP TO 10 KTS FROM
THE SOUTHEAST EARLY TUESDAY.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SMALL
AVIATION...RUSSELL
LONG TERM...BOKSA

000
FXUS63 KDVN 190756 CCA
AFDDVN

AREA FORECAST DISCUSSION...CORRECTED TIME PERIOD OF EXTENDED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
254 AM CDT TUE AUG 19 2008

.SYNOPSIS...
UPPER PATTERN REMAINS STAGNANT AS LOCAL AREA CONTINUES TO FIND ITSELF
IN WEAK NORTHWEST FLOW ALOFT IN BETWEEN EASTERN CONUS LONGWAVE TROUGH
AND REX BLOCK IN PLAINS. UPPER RIDGE OVER NORTHERN ROCKIES IS
BUILDING INTO THE NORTHERN PLAINS... WHILE CUT-OFF LOW SPIRALS
OVER THE TX PANHANDLE. AT THE SFC... HIGH PRESSURE BUILDING DOWN INTO
THE GREAT LAKES HAS SENT BACKDOOR COLD FRONT SURGING SOUTHWARD DOWN
LAKE MI WITH FRONT AT 07Z EXTENDING NEAR A LINE FROM BARABOU/WI DELLS
TO NEAR JANESVILLE WI AND WHEELING IL. FRONT STILL HAS PUSH WITH
3 HR PRESSURE RISES POST FRONTAL OF NEARLY 2 MB... BUT THIS HAS
WEAKENED SINCE LAST EVE WHEN RISES WERE ON THE ORDER OF 3-4 MB. SATL
SHOWS SKIES MAINLY CLEAR MUCH OF THE AREA WITH BATCH OF CLOUDS WITH
BACKDOOR FRONT SLIDING SW THROUGH WI INTO NORTHERN IL. ALSO... SEEING
SOME NOCTURNAL AC DEVELOPMENT ELSEWHERE WITHIN H8-H7 MOIST LAYER FROM
00Z DVN RAOB. DECENT RADIATIONAL COOLING SETUP WITH LIGHT WINDS AND
MAINLY CLEAR SKIES ALONG WITH LOW LEVEL MOISTURE ONCE AGAIN GENERATING
SOME FOG MAINLY IN RIVER VALLEYS AND OTHER LOW LYING AREAS.  ..05..

&&

.SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGE IS WITH BACKDOOR COLD FRONT AND ASSOCIATED PCPN CHCS
AND TEMPS.

MODELS IN GENERAL AGREEMENT THAT THE FRONT WILL LOSE SOME OF ITS PUNCH
TODAY UNDERGOING A BIT OF FRONTOLYSIS AS UPPER RIDGE BUILDS FROM
NORTHERN PLAINS INTO THE UPPER MIDWEST AND CORRESPONDING HEIGHTS
ALOFT INCREASE. THIS LEADS TO WEAKENING LOW LEVEL CONVERGENCE AND
BOUNDARY BECOMING FAIRLY DIFFUSE. DESPITE THIS AND WEAK VERTICAL WIND
PROFILES WITH H85-H5 WINDS AROUND 10 KTS... INSTABILITY AXIS WITH
MLCAPES OF 1500-2000 J/KG AND LI/S -2 TO -4 MAY STILL SPAWN ISOLD
CONVECTION MID-LATE PM IF CONVECTIVE TEMPS REACHED (82-85). LIKELY
JUST A COUPLE THREE STORMS AND WEAK SHEAR SHOULD MEAN LIFE CYCLE
FAIRLY SHORTLIVED. GIVEN VERY LIMITED COVERAGE WITH ANY DEVELOPMENT
SHOULD IT OCCUR...WEAKENING BOUNDARY WITH BUILDING HEIGHTS ALOFT
AND LACK OF COHERENT TRIGGER ATTIM (SHORTWAVE/VORT MAX) WILL OPT NOT
TO MENTION PCPN IN FCST... BUT DID BOOST POPS SOMEWHAT OVER GUIDANCE
NORTH/EAST THOUGH STILL BELOW MENTION. DAY CREW WILL MONITOR TRENDS
AND UPDATE IF NEEDED. TONIGHT...TRANQUIL CONDITIONS WILL PREVAIL
WITH PATCHY CLOUDS AND LIGHT EASTERLY LOW LEVEL FLOW OVERSPREADING THE
CWA AS SFC HIGH CONTINUES TO BUILD DOWN THROUGH THE GREAT LAKES REGION.

AS FOR TEMPS...EXPECT MAXES SIMILAR TO THOSE OF THE PAST FEW DAYS WITH
A FEW LOCALES A DEG OR TWO WARMER CENTRAL/SOUTH WITH H85 TEMPS
SLIGHTLY WARMER. SIDED TOWARD LOW SIDE OF GUIDANCE ON MINS WITH LIGHT
EASTERLY FLOW.

.LONG TERM...WEDNESDAY THROUGH NEXT MONDAY...
QUIET WX EXPECTED ON WEDNESDAY WITH PERHAPS A BIT MORE CLOUDS DUE TO
SLIGHTLY HIGHER DEW POINTS IN THE LOWER ATMOSPHERE. HIGH
TEMPERATURES EXPECTED TO BE QUITE SIMILAR TO TUESDAY. MODELS
INTERESTINGLY HAVE SPED UP THE CUT OFF H5 LOW FOR WED
NIGHT/THURSDAY. WED EVENING SHOULD BE DRY BUT INTERNAL SIGNALS FROM
THE MODELS INDICATE WAA PRECIP SHOULD DEVELOP/MOVE INTO THE CWFA
LATE WEDNESDAY NIGHT AND CONTINUE THROUGH THURSDAY. THEREFORE HAVE
MOVED FORWARD BY 6 HRS POPS INTO LATE WEDNESDAY NIGHT AND HAVE
INCREASED POPS FOR THURSDAY. INCREASE IN CLOUD COVER SHOULD HOLD
DOWN TEMPERATURES ON THURSDAY.

THURSDAY NIGHT ON...MADE NO CHANGES TO THE CURRENT FCST. MODELS
DIFFER ON DETAILS BUT INDICATE A PERIOD OF UNSETTLED WX THROUGH
SATURDAY NIGHT. IF THE 19/00Z ECMWF IS CORRECT...THE UNSETTLED WX
WOULD CONTINUE THROUGH FOR THE ENTIRE WEEKEND.     ..08..

&&

.AVIATION...
PATCHY FOG WITH MVFR VSBYS AND LOCALIZED IFR VSBYS WILL BE FOUND THROUGH
13Z. BACKDOOR COLD FRONT OVER WI INTO NORTHEAST IL WILL CONTINUE
TO SLIDE S/SW WHILE WEAKENING TODAY. ISOLD TSTM IS POSSIBLE ALONG THE
FRONT MID-LATE AFTN OVER NORTHEAST IA AND NORTHWEST IL... BUT
PROBABILITY APPEARS TOO LOW FOR MENTION IN TAFS ATTIM. AS SFC HIGH
BUILDS DOWN THROUGH GREAT LAKES LIGHT EASTERLY WINDS TO OVERSPREAD THE
TERMINALS THIS AFTN AND EARLY EVE. PATCHY FOG POSSIBLE ONCE AGAIN LATE
TONIGHT WITH MAINLY MVFR VSBYS.       ..05..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

05/08

000
FXUS63 KDVN 190755
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
254 AM CDT TUE AUG 19 2008

.SYNOPSIS...
UPPER PATTERN REMAINS STAGNANT AS LOCAL AREA CONTINUES TO FIND ITSELF
IN WEAK NORTHWEST FLOW ALOFT IN BETWEEN EASTERN CONUS LONGWAVE TROUGH
AND REX BLOCK IN PLAINS. UPPER RIDGE OVER NORTHERN ROCKIES IS
BUILDING INTO THE NORTHERN PLAINS... WHILE CUT-OFF LOW SPIRALS
OVER THE TX PANHANDLE. AT THE SFC... HIGH PRESSURE BUILDING DOWN INTO
THE GREAT LAKES HAS SENT BACKDOOR COLD FRONT SURGING SOUTHWARD DOWN
LAKE MI WITH FRONT AT 07Z EXTENDING NEAR A LINE FROM BARABOU/WI DELLS
TO NEAR JANESVILLE WI AND WHEELING IL. FRONT STILL HAS PUSH WITH
3 HR PRESSURE RISES POST FRONTAL OF NEARLY 2 MB... BUT THIS HAS
WEAKENED SINCE LAST EVE WHEN RISES WERE ON THE ORDER OF 3-4 MB. SATL
SHOWS SKIES MAINLY CLEAR MUCH OF THE AREA WITH BATCH OF CLOUDS WITH
BACKDOOR FRONT SLIDING SW THROUGH WI INTO NORTHERN IL. ALSO... SEEING
SOME NOCTURNAL AC DEVELOPMENT ELSEWHERE WITHIN H8-H7 MOIST LAYER FROM
00Z DVN RAOB. DECENT RADIATIONAL COOLING SETUP WITH LIGHT WINDS AND
MAINLY CLEAR SKIES ALONG WITH LOW LEVEL MOISTURE ONCE AGAIN GENERATING
SOME FOG MAINLY IN RIVER VALLEYS AND OTHER LOW LYING AREAS.  ..05..

&&

.SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGE IS WITH BACKDOOR COLD FRONT AND ASSOCIATED PCPN CHCS
AND TEMPS.

MODELS IN GENERAL AGREEMENT THAT THE FRONT WILL LOSE SOME OF ITS PUNCH
TODAY UNDERGOING A BIT OF FRONTOLYSIS AS UPPER RIDGE BUILDS FROM
NORTHERN PLAINS INTO THE UPPER MIDWEST AND CORRESPONDING HEIGHTS
ALOFT INCREASE. THIS LEADS TO WEAKENING LOW LEVEL CONVERGENCE AND
BOUNDARY BECOMING FAIRLY DIFFUSE. DESPITE THIS AND WEAK VERTICAL WIND
PROFILES WITH H85-H5 WINDS AROUND 10 KTS... INSTABILITY AXIS WITH
MLCAPES OF 1500-2000 J/KG AND LI/S -2 TO -4 MAY STILL SPAWN ISOLD
CONVECTION MID-LATE PM IF CONVECTIVE TEMPS REACHED (82-85). LIKELY
JUST A COUPLE THREE STORMS AND WEAK SHEAR SHOULD MEAN LIFE CYCLE
FAIRLY SHORTLIVED. GIVEN VERY LIMITED COVERAGE WITH ANY DEVELOPMENT
SHOULD IT OCCUR...WEAKENING BOUNDARY WITH BUILDING HEIGHTS ALOFT
AND LACK OF COHERENT TRIGGER ATTIM (SHORTWAVE/VORT MAX) WILL OPT NOT
TO MENTION PCPN IN FCST... BUT DID BOOST POPS SOMEWHAT OVER GUIDANCE
NORTH/EAST THOUGH STILL BELOW MENTION. DAY CREW WILL MONITOR TRENDS
AND UPDATE IF NEEDED. TONIGHT...TRANQUIL CONDITIONS WILL PREVAIL
WITH PATCHY CLOUDS AND LIGHT EASTERLY LOW LEVEL FLOW OVERSPREADING THE
CWA AS SFC HIGH CONTINUES TO BUILD DOWN THROUGH THE GREAT LAKES REGION.

AS FOR TEMPS...EXPECT MAXES SIMILAR TO THOSE OF THE PAST FEW DAYS WITH
A FEW LOCALES A DEG OR TWO WARMER CENTRAL/SOUTH WITH H85 TEMPS
SLIGHTLY WARMER. SIDED TOWARD LOW SIDE OF GUIDANCE ON MINS WITH LIGHT
EASTERLY FLOW.

.LONG TERM...TUESDAY THROUGH NEXT SUNDAY...
QUIET WX EXPECTED ON WEDNESDAY WITH PERHAPS A BIT MORE CLOUDS DUE TO
SLIGHTLY HIGHER DEW POINTS IN THE LOWER ATMOSPHERE. HIGH
TEMPERATURES EXPECTED TO BE QUITE SIMILAR TO TUESDAY. MODELS
INTERESTINGLY HAVE SPED UP THE CUT OFF H5 LOW FOR WED
NIGHT/THURSDAY. WED EVENING SHOULD BE DRY BUT INTERNAL SIGNALS FROM
THE MODELS INDICATE WAA PRECIP SHOULD DEVELOP/MOVE INTO THE CWFA
LATE WEDNESDAY NIGHT AND CONTINUE THROUGH THURSDAY. THEREFORE HAVE
MOVED FORWARD BY 6 HRS POPS INTO LATE WEDNESDAY NIGHT AND HAVE
INCREASED POPS FOR THURSDAY. INCREASE IN CLOUD COVER SHOULD HOLD
DOWN TEMPERATURES ON THURSDAY.

THURSDAY NIGHT ON...MADE NO CHANGES TO THE CURRENT FCST. MODELS
DIFFER ON DETAILS BUT INDICATE A PERIOD OF UNSETTLED WX THROUGH
SATURDAY NIGHT. IF THE 19/00Z ECMWF IS CORRECT...THE UNSETTLED WX
WOULD CONTINUE THROUGH FOR THE ENTIRE WEEKEND.     ..08..

&&

.AVIATION...
PATCHY FOG WITH MVFR VSBYS AND LOCALIZED IFR VSBYS WILL BE FOUND THROUGH
13Z. BACKDOOR COLD FRONT OVER WI INTO NORTHEAST IL WILL CONTINUE
TO SLIDE S/SW WHILE WEAKENING TODAY. ISOLD TSTM IS POSSIBLE ALONG THE
FRONT MID-LATE AFTN OVER NORTHEAST IA AND NORTHWEST IL... BUT
PROBABILITY APPEARS TOO LOW FOR MENTION IN TAFS ATTIM. AS SFC HIGH
BUILDS DOWN THROUGH GREAT LAKES LIGHT EASTERLY WINDS TO OVERSPREAD THE
TERMINALS THIS AFTN AND EARLY EVE. PATCHY FOG POSSIBLE ONCE AGAIN LATE
TONIGHT WITH MAINLY MVFR VSBYS.       ..05..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

05/08

000
FXUS63 KDMX 190518 CCA
AFDDMX

AREA FORECAST DISCUSSION...CORRECTED FOR TIME
NATIONAL WEATHER SERVICE DES MOINES IA
1218 AM CDT TUE AUG 19 2008

.DISCUSSION...
QUIET WEATHER WILL CONTINUE THROUGH WEDNESDAY WITH NIL FORCING AS
HIGH PRESSURE DRIFTS SLOWLY EAST.  MODELS BEGINNING TO INDICATE
CUTOFF OVER OKLAHOMA WL BEGIN DRIFTING NORTHWARD LATER WEDNESDAY
THROUGH EARLY FRIDAY AS WESTERLIES DIP INTO THE NORTHERN PORTION OF
THE COUNTRY.  DEEPER MOISTURE WL RETURN NORTHWARD WITH THIS LOW WITH
INCREASING THREAT OF PRECIPITATION ON THURSDAY INTO THURSDAY NIGHT.
HOWEVER...BETTER FORCING ARRIVES LATER FRIDAY INTO FRIDAY NIGHT AS
DECENT SHORTWAVE TRAVERSES ALONG THE CANADIAN BORDER.  THIS WL PUSH
A FRONT TOWARD THE STATE BY LATER FRIDAY WITH INCREASING THREAT FOR
THUNDERSTORMS.  HAVE RAISED POPS DURING THIS TIME IN RESPONSE TO THE
FORCING AND INSTABILITY IN PLACE.  AFTER FRONTAL PASSAGE...WL SEE
DECENT SUBSIDENCE AND COOLER AIR AS WEAK HIGH PRESSURE PUSHES INTO
THE REGION.  THE EXTENDED APPEARS DRY AS THE WEAK HIGH PASSES
THROUGH THE MIDWEST WITH TEMPERATURES REMAINING NEAR NORMAL.

&&

.AVIATION...19/06Z
KFOD HAS DEVELOPED IFR FOG AND MAY BE INTERMMITTENT THROUGH THE
OVERNIGHT. MFVR FOG IS FORECAST BETWEEN 9-13 UTC...WHILE VFR
CEILINGS ARE FORECAST THROUGH THE REMAINDER OF TAF PERIOD...WITH
LIGHT VARIABLE WIND OVERNIGHT BECOMING SUSTAINED UP TO 10 KTS FROM
THE SOUTHEAST EARLY TUESDAY.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

COGIL/RUSSELL

000
FXUS63 KDMX 190513
AFDDMX

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE DES MOINES IA
1210 PM CDT MON AUG 18 2008

.DISCUSSION...
QUIET WEATHER WILL CONTINUE THROUGH WEDNESDAY WITH NIL FORCING AS
HIGH PRESSURE DRIFTS SLOWLY EAST.  MODELS BEGINNING TO INDICATE
CUTOFF OVER OKLAHOMA WL BEGIN DRIFTING NORTHWARD LATER WEDNESDAY
THROUGH EARLY FRIDAY AS WESTERLIES DIP INTO THE NORTHERN PORTION OF
THE COUNTRY.  DEEPER MOISTURE WL RETURN NORTHWARD WITH THIS LOW WITH
INCREASING THREAT OF PRECIPITATION ON THURSDAY INTO THURSDAY NIGHT.
HOWEVER...BETTER FORCING ARRIVES LATER FRIDAY INTO FRIDAY NIGHT AS
DECENT SHORTWAVE TRAVERSES ALONG THE CANADIAN BORDER.  THIS WL PUSH
A FRONT TOWARD THE STATE BY LATER FRIDAY WITH INCREASING THREAT FOR
THUNDERSTORMS.  HAVE RAISED POPS DURING THIS TIME IN RESPONSE TO THE
FORCING AND INSTABILITY IN PLACE.  AFTER FRONTAL PASSAGE...WL SEE
DECENT SUBSIDENCE AND COOLER AIR AS WEAK HIGH PRESSURE PUSHES INTO
THE REGION.  THE EXTENDED APPEARS DRY AS THE WEAK HIGH PASSES
THROUGH THE MIDWEST WITH TEMPERATURES REMAINING NEAR NORMAL.

&&

.AVIATION...19/06Z

KFOD HAS DEVELOPED IFR FOG AND MAY BE INTERMMITTENT THROUGH THE
OVERNIGHT. MFVR FOG IS FORECAST BETWEEN 9-13 UTC...WHILE VFR
CEILINGS ARE FORECAST THROUGH THE REMAINDER OF TAF PERIOD...WITH
LIGHT VARIABLE WIND OVERNIGHT BECOMING SUSTAINED UP TO 10 KTS FROM
THE SOUTHEAST EARLY TUESDAY.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

LONG TERM...BSS
SHORT TERM/AVIATION...FAB/RUSSELL

000
FXUS63 KDMX 190045
AFDDMX

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE DES MOINES IA
400 PM CDT MON AUG 18 2008

.DISCUSSION...
QUIET WEATHER WILL CONTINUE THROUGH WEDNESDAY WITH NIL FORCING AS
HIGH PRESSURE DRIFTS SLOWLY EAST.  MODELS BEGINNING TO INDICATE
CUTOFF OVER OKLAHOMA WL BEGIN DRIFTING NORTHWARD LATER WEDNESDAY
THROUGH EARLY FRIDAY AS WESTERLIES DIP INTO THE NORTHERN PORTION OF
THE COUNTRY.  DEEPER MOISTURE WL RETURN NORTHWARD WITH THIS LOW WITH
INCREASING THREAT OF PRECIPITATION ON THURSDAY INTO THURSDAY NIGHT.
HOWEVER...BETTER FORCING ARRIVES LATER FRIDAY INTO FRIDAY NIGHT AS
DECENT SHORTWAVE TRAVERSES ALONG THE CANADIAN BORDER.  THIS WL PUSH
A FRONT TOWARD THE STATE BY LATER FRIDAY WITH INCREASING THREAT FOR
THUNDERSTORMS.  HAVE RAISED POPS DURING THIS TIME IN RESPONSE TO THE
FORCING AND INSTABILITY IN PLACE.  AFTER FRONTAL PASSAGE...WL SEE
DECENT SUBSIDENCE AND COOLER AIR AS WEAK HIGH PRESSURE PUSHES INTO
THE REGION.  THE EXTENDED APPEARS DRY AS THE WEAK HIGH PASSES
THROUGH THE MIDWEST WITH TEMPERATURES REMAINING NEAR NORMAL.

&&

.AVIATION...19/00Z

OTHER THAN PATCHY LIGHT MVFR FOG OVERNIGHT...VFR CONDITIONS ARE
FORECAST THROUGH THE TAF PERIOD...WITH LIGHT VARIABLE WIND
OVERNIGHT. WINDS WILL BECOME SUSTAINED UP TO 10 KTS FROM THE
SOUTHEAST EARLY TUESDAY.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

LONG TERM...BSS
SHORT TERM/AVIATION...FAB/RUSSELL

000
FXUS63 KDMX 182056
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
400 PM CDT MON AUG 18 2008

.DISCUSSION...
QUIET WEATHER WILL CONTINUE THROUGH WEDNESDAY WITH NIL FORCING AS
HIGH PRESSURE DRIFTS SLOWLY EAST.  MODELS BEGINNING TO INDICATE
CUTOFF OVER OKLAHOMA WL BEGIN DRIFTING NORTHWARD LATER WEDNESDAY
THROUGH EARLY FRIDAY AS WESTERLIES DIP INTO THE NORTHERN PORTION OF
THE COUNTRY.  DEEPER MOISTURE WL RETURN NORTHWARD WITH THIS LOW WITH
INCREASING THREAT OF PRECIPITATION ON THURSDAY INTO THURSDAY NIGHT.
HOWEVER...BETTER FORCING ARRIVES LATER FRIDAY INTO FRIDAY NIGHT AS
DECENT SHORTWAVE TRAVERSES ALONG THE CANADIAN BORDER.  THIS WL PUSH
A FRONT TOWARD THE STATE BY LATER FRIDAY WITH INCREASING THREAT FOR
THUNDERSTORMS.  HAVE RAISED POPS DURING THIS TIME IN RESPONSE TO THE
FORCING AND INSTABILITY IN PLACE.  AFTER FRONTAL PASSAGE...WL SEE
DECENT SUBSIDENCE AND COOLER AIR AS WEAK HIGH PRESSURE PUSHES INTO
THE REGION.  THE EXTENDED APPEARS DRY AS THE WEAK HIGH PASSES
THROUGH THE MIDWEST WITH TEMPERATURES REMAINING NEAR NORMAL.

&&

.AVIATION...18/18Z
VFR CONDITIONS WL CONTINUE TO BE WIDESPREAD THROUGH THIS EVENING
WITH SOME MVFR CONDITIONS AFTER MIDNIGHT WITH PATCHY MIST AND FOG.
WNDS WL RMN LIGHT.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

LONG TERM...BSS
SHORT TERM/AVIATION...FAB