000
FXUS63 KGRB 290933
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
433 AM CDT FRI AUG 29 2008

.SHORT TERM...TODAY THROUGH SATURDAY. PATCHY FOG WILL END EARLY
WITH SUNNY SKIES AND WARM TEMPERATURES EXPECTED TODAY. DRY AIR
WILL ALLOW FOR TEMPERATURES TO CLIMB INTO THE LOW 80S IN MANY
PLACES. SHOULD BE GENERALLY CLEAR TONIGHT...BUT EXPECT
TEMPERATURES TO BE WARMER THAN THIS MORNING AS THERE SHOULD MORE
OF A BREEZE AS BUFKIT FORECAST SOUNDINGS SHOW 25 TO 30 KNOTS ABOUT
1000` ABOVE THE GROUND. SATURDAY SHOULD BE ANOTHER SUNNY DAY...AND
WITH A WARMER START IT COULD REACH 85 DEGREES IN PLACES AWAY FROM
THE LAKE.

.LONG TERM...SAT NGT THRU NXT THU. MAIN FCST FOCUS THRU THE
HOLIDAY WEEKEND WL BE ON TEMPS AS A DRY WEATHER REGIME KEEPS ANY
PCPN AWAY. FCST CHALLENGE TOWARD THE MIDDLE OF NXT WEEK WL BE PCPN
CHCS AS SEVERAL WEATHER FEATURES WL HAVE TO BE DEALT WITH AND
TIMING IS SUSPECT AT THIS POINT IN TIME.

A RATHER AMPLIFIED MEAN FLOW TO EXIST OVR THE CONUS SAT NGT WITH
UPR TROFS OVR THE WRN AND NE SECTIONS OF THE COUNTRY AND AN UPR
RDG TO STRETCH FROM THE MO VALLEY NWD INTO THE WRN GREAT LKS. THE
SFC HI PRES TO RESIDE OVR THE GREAT LKS AS WELL...THUS EXPECT
MOSTLY CLR SKIES AND LGT WNDS FOR THE FCST AREA. THERE COULD BE
SOME PATCHY FOG AROUND...BUT WL HOLD OFF MENTIONING FOR NOW AS THE
EXTENT OF ANY FOG IN QSTN. CLR SKIES/LGT WNDS/DRY AIRMASS WL ALLOW
FOR A QUICK DROP IN TEMPS WITH MOST LOCATIONS SETTLING INTO THE
50S. SFC HI SHIFTS A BIT FARTHER EAST ON SUNDAY AND THIS ALLOWS
FOR A RETURN FLOW TO GRADUALLY DVLP OVR WI. THE UPR RDG REMAINS
PARKED OVRHD AND WITH 8H TEMPS HOLDING IN THE UPR TEENS...A WARM
DAY ON TAP FOR NE WI. EXPECT TO SEE TEMPS WARM WELL INTO THE 80S
OVR INLAND LOCATIONS WHILE IMMEDIATE LKSHR AREAS HOLD IN THE UPR
70S THANKS TO S-SE WNDS.

THE WRN CONUS UPR TROF MOVS INLAND A BIT FARTHER...BUT WL BE
BLOCKED BY THE STG UPR RIDGING OVR THE ERN CONUS SUNDAY NGT. MORE
IN THE WAY OF BNDRY LYR WNDS ARE EXPECTED TO PREVENT TEMPS FROM
FALLING AS FAR AS PREV NGTS. MOST LOCATIONS OVR NE WI SHOULD SEE
MIN TEMPS IN THE UPR 50S OR LWR 60S UNDER CLR SKIES. ONLY A SLGT
EWD SHIFT OF THE KEY WEATHER FEATURES EXPECTED ON MON WITH THE UPR
TROF REACHING THE ROCKIES AND THE UPR RDG MOVG INTO THE ERN GREAT
LKS. THERE IS ALSO THE UNKNOWN LOCATION OF TROPICAL SYSTEM
`GUSTAV` WHICH IS PROGGED TO BE CHURNING OVR THE GULF. TYPICALLY...
TROPICAL SYSTEMS TEND TO SLOW THE EWD MOVEMENT OF SYSTEMS THRU THE
CONUS...THUS A CONTINUATION OF DRY AND WARM CONDITIONS TO PREVAIL
FOR NE WI ON MON. MAX TEMPS AWAY FROM THE LAKE COULD EASILY REACH
THE UPR 80S WITH AN ISOLATED 90 DEGS PSBL OVR SANDY SOIL SECTIONS.

THE UPR TROF IS FCST TO BEGIN LIFTING NE TOWARD THE HI PLAINS/NRN
PLAINS VCNTY BY TUE AS A 100 KT UPR JET ROUNDS THE BASE OF THE
TROF. `GUSTAV` EXPECTED TO BE MOVG INLAND SOMEWHERE OVR THE DEEP
SOUTH WHILE THE UPR RDG REMAINS NEARLY STNRY OVR THE ERN GREAT
LKS. NE WI WL CONT TO SEE SOUTHERLY WNDS WHICH SHOULD BEGIN
TAPPING GULF MSTR. AN INCREASE IN DEW PTS WL ADD SOME HUMIDITY TO
THE AIR WITH TEMPS A COUPLE OF DEGS COOLER THAN MON.

QSTNS REMAIN AS TO THE EVENTUAL INTERACTION BETWEEN THE REMNANTS
OF `GUSTAV`...THE UPR TROF AND AN EWD MOVG CDFNT DURING THE MIDDLE
OF NXT WEEK. THE 00Z GFS MAINTAINS THAT THE SHRTWV TROF/CDFNT WL
MOV THRU WI ON WED AND BE TO OUR SOUTH AND EAST BEFORE THE MSTR
FROM `GUSTAV` CAN REACH US. THE ECMWF ON THE OTHER HAND BRINGS
`GUSTAV` WELL INLAND WITH ITS MSTR GETTING HOOKED INTO THE SW FLOW
ALOFT AND PUSHING INTO WI WED AND THU. SUCH A VAST DIFFERENCE
COMBINED WITH THE GREAT UNKNOWN OF WHERE `GUSTAV` MAKES LANDFALL...
PREVENTS ANY CHG TO THIS PART OF THE FCST AT THIS TIME.
&&

.AVIATION...PATCHY GROUND FOG WILL CLEAR EARLY WITH GREAT FLYING
WEATHER EXPECTED TODAY. DO NOT EXPECT FOG TONIGHT AS THERE WILL BE
SOME WIND JUST ABOVE THE GROUND. IN FACT MARGINAL LOW LEVEL WIND
SHEAR POSSIBLE BETWEEN 06Z AND 12Z TONIGHT WITH LIGHT SOUTHWEST WINDS
AT THE SURFACE AND WEST WINDS OF 30 KNOTS AT 1000` AGL.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
RDM/KALLAS

000
FXUS63 KMKX 290907
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
407 AM CDT FRI AUG 29 2008

FORECAST FOCUS ON FOG THIS MORNING...QUIET WEATHER THROUGH THE
WEEKEND.

LATEST WATER VAPOR IMAGERY INDICATED A BROAD UPPER LEVEL TROUGH
OVER THE WESTERN GREAT LAKES REGION. SLIGHT UPSTREAM RIDGING WAS
NOTED OVER THE PACIFIC NORTHWEST...WITH AN AMPLIFIED DOWNSTREAM
RIDGE OVER FAR EASTERN CANADA. AT THE SURFACE....A COLD FRONT WAS
EXITING THE REGION...WHILE HIGH PRESSURE WAS LOCATED OVER THE
CENTRAL PLAINS.

.SHORT TERM...TODAY THROUGH TUESDAY...

DECOUPLED WINDS AND DEW POINTS IN THE UPPER 50S TO MID 60S HAVE
COMBINED TO BRING AREAS OF FOG. SOME HAS BEEN DENSE IN
SPOTS...WITH A COUPLE LOCATIONS GOING BELOW 1/4 MILE AT TIMES.
HOWEVER...THESE OCCURRENCES HAVE BEEN ON AND OFF SO FAR
OVERNIGHT...GIVEN LIGHT WINDS BEING OBSERVED AT TIMES.

FEEL THAT THE BEST WAY TO HANDLE THIS WOULD BE TO MENTION AREAS OF
FOG WITH PATCHY DENSE FOG EARLY THIS MORNING. DO NOT SEE A NEED
FOR A DENSE FOG ADVISORY AT THIS TIME...AS DENSE FOG IS NOT
WIDESPREAD ENOUGH FOR A LONG ENOUGH TIME TO WARRANT ITS ISSUANCE.
MIXING WITH DAYTIME HEATING SHOULD END FOG BY MID MORNING.

HIGH PRESSURE THEN EXPECTED TO MOVE ACROSS THE REGION LATER TODAY
THROUGH SATURDAY...THEN MOVE SLOWLY EASTWARD THROUGH TUESDAY. THE
HIGH SHOULD COMBINE WITH AN AMPLIFIED UPPER LEVEL RIDGE TO PROVIDE
A DRY STRETCH OF WEATHER FOR LABOR DAY WEEKEND. LOWER DEW POINTS
SHOULD BRING A MORE COMFORTABLE AIRMASS. ONSHORE WINDS EACH DAY
WILL KEEP HIGH TEMPERATURES IN THE 70S NEAR THE LAKE...WITH WARMER
80S INLAND.

.LONG TERM...TUESDAY NIGHT THROUGH THURSDAY...

DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR DURING THIS TIME. THE
GFS TAKES A COLD FRONT THROUGH THE AREA ON WEDNESDAY...THEN EXITS
TO THE SOUTH WEDNESDAY NIGHT. THE ECMWF KEEPS THIS FEATURE WEST OF
THE STATE. MORE DIFFERENCES ABOUND FOR LATER IN THE WEEK WITH THE
FOLLOWING SYSTEM. GIVEN THESE DIFFERENCES...WILL MAINTAIN WORDING
FOR THIS PERIOD...AND WILL WATCH THE LONG RANGE MODELS FOR FUTURE
CONTINUITY BEFORE MAKING MAJOR CHANGES TO THE FORECAST.

&&

.AVIATION...

AREAS OF LIFR FOG THROUGH 13Z. AS LOW LEVEL WINDS INCREASE A BIT
AS SURFACE LOW EXITS SOUTHERN LAKE MICHIGAN AREA...VISIBILITIES
SHOULD IMPROVE. SCATTERED AFTERNOON CU ARND 4 THSD FT.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

SHORT/LONG TERM...08/WOOD
AVIATION/MARINE...06/HENTZ

000
FXUS63 KARX 290759
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
259 AM CDT FRI AUG 29 2008

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

WEATHER CONTINUES TO LOOK VERY TRANQUIL FOR HOLIDAY WEEKEND.

SHORT WAVE ENERGY REMAINS MAINLY OVER SOUTHERN CANADA EARLY THIS
MORNING AS MEAN TROUGH AXIS HAS SHIFTED EAST OF THE AREA. SURFACE
FRONTAL BOUNDARY IS ALSO EAST AND SOUTH OF THE AREA BUT WITH SUCH
WEAK SURFACE FLOW...DEW POINTS HAVE HELD UP CLOSER TO BOUNDARY
LEADING TO PATCHY FOG. MEANWHILE SURFACE HIGH PRESSURE RIDGE
STARTING TO NOSE IN FROM THE PLAINS WITH DRIER AIR ADVECTING IN
SLOWLY FROM THE NORTHWEST.

AS ENERGY DEVELOPS MEAN TROUGH ACROSS NORTHWEST STATES NEXT FEW
DAYS...UPPER RIDGE OVER MIDWEST WILL MAKE FOR QUIET WEEKEND. FOCUS
WILL BE ON TEMPERATURES WITH GRADUAL WARMUP EACH DAY...2-3 DEG C PER
DAY.

COULD CONTINUE TO SEE SOME PATCHY VALLEY FOG FOR A FEW MORE MORNINGS
GIVEN SURFACE HIGH PRESSURE REGIME BUT SHOULD NOT BE A BIG DEAL.

RETURN FLOW ESTABLISHES MORE OVER THE PLAINS INTO WESTERN MINNESOTA
LATE IN HOLIDAY WEEKEND BUT STILL LOOKS LIKE CONVECTION WOULD REMAIN
WELL WEST OF THE AREA.

.LONG TERM...LABOR DAY THROUGH THURSDAY

TROUGH OVER WEST COAST WILL BEGIN TO SHIFT NORTHEAST AND EJECT SHORT
WAVE TROUGH ENERGY INTO UPPER MIDWEST AFTER LABOR DAY IT APPEARS.
MINOR DIFFERENCES REMAIN IN MEDIUM RANGE GUIDANCE AND COMBINED WITH
POSSIBLE TROPICAL SYSTEM INTERACTIONS AS WEEK PROGRESSES...
CONFIDENCE IN RAIN CHANCES ON DAYS 5 AND 6 ARE LOW. MINOR POPS STILL
LOOK ON TRACK AS SOUTHWEST FLOW DEVELOPS IN THAT TIME FRAME. MAY
EVEN HAVE TO ADD POPS IN LATER PERIODS IF MOSITURE FROM GUSTAV GETS
PULLED NORTHWARD LIKE 29.00Z ECMWF IS ADVERTISING.

&&

.AVIATION...

THE KLSE BUFKIT SOUNDINGS CONTINUE TO SHOW THE BOUNDARY IS WELL
MIXED ABOVE 100 FEET. THIS IS PREVENTING A DEEP LAYER OF VALLEY FOG
FROM DEVELOPING IN THE MISSISSIPPI CHANNEL. THERE HAVE BEEN A FEW
REPORTS OF LESS THAN 2 MILES. AS A RESULT...I MAY HAVE TO ADD BCFG
AT THIS TAF SITE THIS MORNING. WHILE WIDESPREAD DENSE FOG IS HAVING
A HARD TIME FORMING IN THIS VALLEY...THERE ARE REPORTS OF DENSE FOG
IN THE WISCONSIN RIVER VALLEY. THIS VALLEY TENDS TO BE MORE
SHELTERED WITH NORTHWEST FLOW ALOFT...AND AS A RESULT...YOU ARE MORE
APT TO SEE WIDESPREAD DENSE FOG IN THIS SITUATION. THE FOG IN THIS
RIVER VALLEY WILL LIKELY BURN OFF BY 29/1430Z.

A SHORT WAVE TROUGH WILL MOVE NORTHEAST OF THE AREA TONIGHT. THIS
MAY BRING SOME SCATTERED MID LEVEL CLOUDS INTO THE REGION LATE THIS
AFTERNOON AND TONIGHT. IN ADDITION TO THE CLOUDS...THERE SHOULD BE
ENOUGH MIXING IN THE BOUNDARY LAYER TO PRECLUDE DENSE FOG AT THE
KLSE TAF. HOWEVER IN THE MORE SHELTERED RIVER VALLEY SUCH AS THE
WISCONSIN...THERE WILL LIKELY ONCE AGAIN BE SOME DENSE FOG.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...SHEA
AVIATION..........BOYNE

000
FXUS63 KGRB 282026
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
326 PM CDT THU AUG 28 2008

.SHORT TERM...TONIGHT AND FRIDAY. COLD FRONT NOW EXTENDS FROM NEAR
IMT TO WAUTOMA...WITH CLOUDS CLEARING BEHIND. LOW CLOUDS WITH AND
AHEAD OF FRONT HAS NOT ALLOWED FOR SIG DESTABILIZATION OF
ATMOSPHERE...THOUGH STRONG SHEAR WITH 100+ JET PUSHING INTO LAKE
SUPERIOR ENOUGH TO GET SOME ACTIVITY GOING THIS AFTERNOON OVER
EASTERN WI. MORE DIURNAL TYPE ACTIVITY OVER NORTHERN MN ASSOCIATED
WITH COLD POCKET WILL STAY WEST/NORTH OF AREA. HIGH PRESSURE
BUILDING IN TONIGHT WILL LEAD TO LIGHT WINDS...SOME PATCHY FOG
WEST WHERE RAINFALL WAS HEAVIER EARLY THIS MORNING. UPSTREAM TEMPS
NOT AS WARM AS GUIDANCE...THOUGH WITH WESTERLY FLOW AND
SUN...WILL GO SLIGHTLY BELOW FOR HIGHS FRI.

.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...MAIN FCST CONCERNS
ARE TEMPERATURES THROUGHOUT THE PERIOD...AND PCPN CHCS ASSOC WITH
A SLOW MOVG COLD FRONT AND PSBL INTERACTION WITH TROPICAL MOISTURE
FROM GUSTAV DURING THE MID-LATE PART OF NEXT WEEK.

FCST STARTS OFF PRETTY STRAIGHT-FORWARD AS HIGH PRESSURE AT THE SFC
AND ALOFT SHIFTS SLOWLY EAST THROUGH THE GREAT LKS AND INTENSIFIES.
THIS WILL RESULT IN ANOTHER PROLONGED DRY PERIOD...WITH DEVELOPING
RETURN FLOW LEADING TO MUCH ABOVE NORMAL MAX TEMPS. HAVE BOOSTED
MAX TEMPS WELL INTO THE 80S FOR THE WEEKEND AND EARLY NEXT WEEK.
WITH A MORE AMPLIFIED FLOW PATTERN DEVELOPING...MODELS HAVE
SLOWED THE PROGRESSION OF THE APPROACHING COLD FRONT FOR THE MID
PART OF THE NEXT WORK WEEK. WITH THIS IN MIND...HAVE OPTED TO REMOVE
PCPN FROM THE TUES FCST.

FCST GETS TOUGH FOR THE TUES NGT-THU PERIOD...AS MODELS DISAGREE ON
HOW QUICKLY THE FRONT WILL MOVE THROUGH THE WSTRN GREAT LKS REGION.
THE GFS (WITH SUPPORT FROM MOST OF IT`S ENSEMBLE MEMBERS) QUICKLY
PUSHES THE FRONT THROUGH WI TUES NGT...AND MOVES IT INTO THE OHIO
VALLEY WEDS NGT INTO THURS. ON THE OTHER END OF THE SPECTRUM...THE
ECMWF MOVES THE FRONT THROUGH WI ON WEDS...AND STALLS IT JUST TO
OUR EAST WEDS NGT INTO THURS. THIS SETS THE STAGE FOR A POTENTIAL
OVERRUNNING EVENT AS TROPICAL MOISTURE FROM GUSTAV SURGES NORTH.
SINCE THE ECMWF IS USUALLY QUICKER TO PICK UP ON SIGNIFICANT
TRENDS IN THE MEDIUM RANGE...HAVE OPTED TO LEAN THE FCST IN ITS
DIRECTION. HAVE ADDED POPS FOR WEDS NGT INTO THURS... WITH THE
HIGHEST POPS IN OUR SE COUNTIES...CLOSER TO THE FRONT. CONFIDENCE
IS LOW FOR THIS PART OF THE FCST.
&&

.AVIATION...COLD FRONT MOVING THROUGH STATE WITH CLEARING
EXPECTED WEST TO EAST THIS EVENING...WITH VFR CIGS EXPECTED ALL
SITES AFT 01Z. SCATTERED SHOWER/TSTM ACTIVITY EXPECTED GRB AND
EASTERN AIRPORTS THROUGH 00Z. CLEARING SKIES AND LIGHT WINDS WILL
LEAD TO PATCHY FOG CENTRAL AND NORTH CENTRAL TAF SITES GIVEN
LINGERING MOISTURE FROM LAST NIGHTS RAINS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
TE/KIECKBUSCH

000
FXUS63 KMKX 281957
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
256 PM CDT THU AUG 28 2008

.DISCUSSION...FORECAST FOCUS ON CONVECTION THIS EVENING AND
EXTENDED PERIOD OF DRY WEATHER.

.SHORT TERM...SEVERAL FACTORS REMAIN IN PLACE FOR CONVECTION TO
DEVELOP INTO THE EVENING HOURS. AXIS OF INSTABILITY WITH LIFTED
INDEX VALUES AROUND -6 AHEAD OF SURFACE FRONTAL BOUNDARY IN AREA
OF PARTLY CLOUDY SKIES WEST OF CWA FORECAST TO ADVECT EASTWARD.
RUC 850 MILLIBAR THERMAL RIDGE LEANING OVER CWA FROM THE WEST OVER
SHALLOW NOSE OF SURFACE DEW POINTS IN THE MIDDLE AND UPPER 60S
WILL AWAIT ARRIVAL OF 500 MILLIBAR TRIGGER IN THE FORM OF A
VORTICITY MAXIMA OVER SOUTHERN MINNESOTA TO ENHANCE CONVECTION.
WILL WAIT UNTIL LAST MINUTE TO SEE IF CONVECTION WILL BE MORE
SCATTERED THAN WIDESPREAD.

.LONG TERM...PROGS IN VERY GOOD AGREEMENT WITH ESTABLISHMENT OF
LARGE BLOCKING HIGH OVER GREAT LAKES REGION IN WAKE OF DEPARTING
FRONT. QUIET WEATHER PATTERN CONTINUES THROUGH LABOR DAY WEEKEND.
AS HIGH SLIDES TO EAST COAST BY TUESDAY SOUTHWEST FLOW RETURNS TO
CWA. ECMWF PROG MORE THAN GFS PROG TRIES TO INJECT MORE MOISTURE
TOWARD AREA FROM GUSTOV ESPECIALLY IN THE 1000-850 MILLIBAR LAYER.
THE 1000-850 MILLIBAR WINDS BY TUESDAY NIGHT CONNECT THIS MOIST
FLOW FROM GULF OF MEXICO INTO WESTERN GREAT LAKES REGION WITH
APPROACHING WEAK SURFACE FRONT TRIGGERING CONVECTION. ALTHOUGH GFS
LESS THAN ENTHUSIASTIC WITH THIS MOISTURE CONNECTION FEEL SLOWLY
APPROACHING FRONTAL BOUNDARY WILL STILL BE WORTHY OF CHANCY
PRECIPITATION TOWARD THE END OF NEXT WEEK.

&&

.AVIATION...HIGH CIGS SHIFTED EASTWARD EARLY THIS AFTERNOON AND
CU/STRATOCU DEVELOPED IN THE WAKE. WITH AFTERNOON HEATING...IT IS
POSSIBLE FOR THUNDERSTORMS TO DEVELOP AHEAD OF AND ALONG A COLD
FRONT THAT WILL TRACK ACROSS SOUTHEAST WI EARLY THIS EVENING.
HOWEVER...MODEL GUIDANCE IS INSISTING THAT THE MAIN THREAT OF
SHOWERS AND THUNDERSTORMS WILL BE TO THE SOUTH AND NORTH OF
KMSN/KMKE/KENW. WITH LOW CHANCE OF TSTORMS...DID NOT PUT
PREVAILING PCPN IN THE TAFS.

BEHIND THE FRONT...VERY DRY AIR SINKS INTO THE REGION AND SKIES
WILL CLEAR OVERNIGHT. WINDS WILL BE LIGHT BEHIND THE FRONT AND
THIS SHOULD ALLOW FOR FOG DEVELOPMENT NEAR SUNRISE...MAINLY AT
KMSN/KENW.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

SHORT/LONG TERM...17/ZAJDEL
AVIATION/MARINE...13/CRONCE

000
FXUS63 KARX 281939
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
239 PM CDT THU AUG 28 2008

.SHORT TERM...THROUGH SATURDAY NIGHT

MAIN FORECAST CONCERN IS WITH RAIN CHANCES THIS EVENING AND THEN
TEMPERATURES THROUGH THE PERIOD.

SURFACE ANALYSIS THIS AFTERNOON SHOWS THE MAIN COLD FRONT
EXTENDING FROM ABOUT KIMT ACROSS THE EASTERN PARTS OF THE FORECAST
AREA TO KMCI. SECONDARY COLD FRONT WAS JUST ENTERING NORTHWEST
MINNESOTA.

WATER VAPOR AND RUC ANALYSIS INDICATE THE MAIN SHORT WAVE TROUGH
EXTENDS FROM NORTHERN WISCONSIN INTO EASTERN SOUTH DAKOTA. SECONDARY
SHORT WAVE TROUGH WAS NEAR THE INTERNATIONAL BORDER OVER EXTREME
SOUTHWEST ONTARIO. WITH THE MAIN SHORT WAVE TROUGH ALMOST ON TOP
OF THE FORECAST AREA...ALL THE SIGNIFICANT SYNOPTIC SCALE FORCING
HAS MOVED DOWNSTREAM OF THE FORECAST AREA. THE SURFACE COLD FRONT
SHOULD BE VERY CLOSE TO OR OUT OF THE FORECAST AREA BY 00Z SO NOT
ANTICIPATING THE NEED FOR ANY EVENING POPS ACROSS THE FAR EASTERN
OR SOUTHERN SECTIONS OF THE FORECAST AREA. VISIBLE SATELLITE
SHOWING AN AGITATED CUMULUS FIELD ACROSS NORTHERN MINNESOTA WITH
KBDE REPORTING A THUNDERSTORM AT 19Z. THIS ACTIVITY WILL LIKELY
BUILD A LITTLE SOUTH ALONG THE COLD FRONT IN THE WEAK ML CAPE AXIS
WITH VALUES TO AROUND 1000 J/KG INTO FAR NORTHERN WISCONSIN. THE
28.18Z RUC KEEPS THE CAPE AXIS NORTH OF THE FORECAST AREA AND THEN
QUICKLY DISSIPATES IT BY 01Z. THE 28.15Z ARXRUCWRF SEEMS TO HAVE A
GOOD HANDLE ON THIS SECONDARY FRONT AND SHORT WAVE TROUGH AND ONLY
BRINGS THE CONVECTION AS FAR SOUTH AS DULUTH AND THEN MOVES IT OFF
INTO THE U.P. OF MICHIGAN.

AFTER THIS EVENING...HIGH PRESSURE AT THE SURFACE WITH RIDGING
ALOFT BUILDS OVER THE UPPER MIDWEST FOR THE REMAINDER OF THE
PERIOD. LITTLE IN THE WAY OF CLOUD COVER EXPECTED...EXCEPT FOR THE
POSSIBILITY OF A LITTLE MORE CLOUDS ACROSS THE NORTH FRIDAY NIGHT
INTO SATURDAY AS A WEAK BOUNDARY ZIPS BY TO THE NORTHEAST. DEW
POINTS EXPECTED TO REMAIN IN THE 50S THROUGH THE PERIOD WHICH
SHOULD ALLOW FOR SOME PRETTY GOOD DIURNAL RANGES...ESPECIALLY
LATER IN THE PERIOD WHEN THE HIGH SLIPS OFF THE EAST AND ALLOWS
SOUTH WINDS TO BRING SOME WARMER AIR BACK INTO THE AREA. HIGHS
EXPECTED TO STEADILY CLIMB EACH DAY REACHING THE MIDDLE 80S BY
SUNDAY WITH OVERNIGHT LOWS MAINLY IN THE 50S.

.LONG TERM...SUNDAY THROUGH THURSDAY

MEDIUM RANGE MODELS IN DECENT AGREEMENT THROUGH THE PERIOD WITH
GENERAL SYNOPTIC SCALE FLOW/PATTERN. RIDGING WILL BUILD OVER THE
EASTERN CONUS IN RESPONSE TO THE TROPICAL SYSTEMS COMING ACROSS THE
GULF AND THE ATLANTIC. TROUGHING WILL DIG INTO THE WESTERN CONUS AND
REMAIN UNTIL LATE IN THE PERIOD. THIS IS WHERE MODEL DIFFERENCES
START TO SHOW UP IN HOW FAST THIS TROUGHING WILL MOVE EAST AND START
TO RIDE UP AND OVER THE EASTERN CONUS RIDGING. THE 28.06Z
OPERATIONAL GFS AND 28.00Z GFS ENSEMBLE MEANS ARE QUICKER TO BRING
THIS TROUGH NORTHEAST THAN THE OPERATIONAL 28.00Z ECMWF. WILL BLEND
THESE TWO SOLUTIONS AND HAVE POPS AS THE SURFACE COLD FRONT COMES
THROUGH THE AREA TUESDAY OR TUESDAY NIGHT INTO WEDNESDAY.

&&

.AVIATION...

LATEST 17Z SURFACE ANALYSIS INDICATING COLD FRONT EXTENDING FROM
NORTHEAST WISCONSIN INTO SOUTH CENTRAL IOWA. LATEST VISIBLE
SATELLITE IMAGERY INDICATING LOW STRATUS DECK ALONG AND AHEAD OF
COLD FRONT. CEILING HEIGHTS AHEAD OF COLD FRONT WERE IN THE MVFR
RANGE. AS THE COLD FRONT PASSES THIS AFTERNOON...WINDS WILL SHIFT TO
THE NORTHWESTERLY DIRECTION AT BOTH TAF SITES. COLD FRONT HAS PASSED
THROUGH KRST AND WILL WITHIN THE NEXT HOUR OR TWO AT KLSE. HIGH
PRESSURE BUILDING IN FROM THE NORTHERN PLAINS STATES WILL BRING A
MUCH DRIER AIRMASS AND SKIES WILL BECOME CLEAR BY 00Z FRIDAY AT BOTH
TAF SITES. WITH HIGH PRESSURE IN CONTROL THROUGH THE LABOR DAY
WEEKEND...MAY NEED TO WATCH VALLEY FOG POTENTIAL AT KLSE INTO THE
WEEKEND.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...04
AVIATION...DTJ

000
FXUS63 KARX 281546
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1046 AM CDT THU AUG 28 2008

.UPDATE...LATEST 15Z SURFACE ANALYSIS INDICATES COLD FRONT EXTENDING
FROM NORTHERN WISCONSIN INTO NORTH CENTRAL IOWA. LATEST 28.15Z LAPS
INDICATING VERY WEAK SURFACE MOISTURE CONVERGENCE ALONG COLD FRONT.
THIS IS EVIDENT WITH METARS OUT AHEAD OF FRONT REPORTING
SOUTHWESTERLY WIND DIRECTION AND WEST TO NORTHWESTERLY WIND
DIRECTION BEHIND COLD FRONT. LATEST 28.12Z NAM ALSO INDICATING WEAK
SURFACE MOISTURE CONVERGENCE ALONG COLD FRONT AND MOVES FRONT INTO
EXTREME SOUTHEASTERN PORTION OF FORECAST AREA BY 21Z THURSDAY. WITH
STRATUS DECK OUT AHEAD OF THE FRONT...INSTABILITY WILL BE LIMITED.
LATEST 28.12Z RUC INDICATING 500 TO 800 J/KG SURFACE BASE CAPE
ACROSS EXTREME SOUTHERN GRANT AND CLAYTON COUNTIES BY 21Z THURSDAY.
DUE TO WEAK MOISTURE CONVERGENCE AND INSTABILITY ALONG COLD
FRONT...HAVE UPDATED FORECAST TO REDUCE PRECIPITATION CHANCES ACROSS
FORECAST AREA...ESPECIALLY EASTERN FORECAST AREA.

DTJ

&&

.PREV DISCUSSION... /ISSUED 234 AM CDT THU AUG 28 2008/


.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

FORECAST CHALLENGE IS IN FIRST 15 HOURS AS NORTHERN FLOW SHORT WAVE
TROUGH ENERGY MOVES THROUGH TODAY WITH CONVECTIVE THREAT. AFTER THAT
IT LOOKS LIKE A QUIET HOLIDAY WEEKEND ON TAP.

FAIRLY POTENT SHORT WAVE TROUGH IS MOVING ALONG THE CANADIAN AND
NORTH DAKOTA BORDER EARLY THIS MORNING. MID/UPPER LEVEL JET CRASHING
OUT OF THE NORTHERN ROCKIES INTO THE DAKOTAS THIS MORNING HAS SET UP
STRONG LOW LEVEL FLOW IN RESPONSE WITH 55 KTS AROUND 850 MB ON OAX
VAD WIND PROFILE AS OF 06Z. THIS HAS GENERATED QUITE A BIT OF
CONVECTION OVERNIGHT WITH MUCAPES STILL IN 500 TO 1000 J/KG RANGE
MAINLY WEST OF MISSISSIPPI RIVER. BASED ON LAPS SOUNDINGS APPEARS
ELEVATED CONVECTION IS DEVELOPING AROUND 800 MB SO MAIN THREAT IS
SOME HAIL AND ACTUALLY STORMS HAVE BEEN WEAKENING AS THEY SHIFT
EAST...EVEN WITH DECENT DYNAMIC FORCING FOR LATE AUGUST. MUCH NEEDED
RAINFALL WILL PROBABLY STAY UNDER AN INCH FOR NEARLY EVERYONE.

AS SHORT WAVE ENERGY CONTINUES EAST...STRONGER SURFACE FRONT OVER
NORTHERN PLAINS WILL LIKELY MERGE WITH NEARBY QUASI-STATIONARY
BOUNDARY AND THEN MOVE EAST THIS AFTERNOON. SHORT TERM MODEL
GUIDANCE SUPPORTS THIS AND GIVEN PROGRESSIVE NATURE WOULD AGREE THAT
MAIN RAIN THREAT WILL BE THIS MORNING. HAVE ALREADY DROPPED RAIN
THREAT FOR MOST AREAS THIS EVENING AND LEFT CENTRAL AND SOUTHWEST
WISCONSIN COUNTIES IN FOR JUST EARLY EVENING HOURS BEFORE RETURN TO
DRY SPELL.

AFTER THAT HEIGHTS START TO RISE AND RIDGE BUILDS ACROSS CENTRAL
U.S. FOR WHAT LOOKS LIKE QUIET SEVERAL DAYS. SURFACE RIDGE SETTLES
IN FOR SEASONAL TEMPERATURES AND DRY AIRMASS. GIVEN THIS AND
CLIMATOLOGICAL FAVORED TIME OF YEAR...RIVER VALLEY FOG POSSIBLE A
FEW MORNINGS IN THERE AS WELL.

.LONG TERM...SUNDAY THROUGH WEDNESDAY

UPPER TROUGH THAT DEVELOPS ACROSS PACIFIC NORTHWEST THIS WEEKEND
PROGGED TO EJECT EAST EARLY NEXT WEEK BUT SUBTLE DIFFERENCES IN
MEDIUM RANGE GUIDANCE ON TRACK OF TROUGH. GENERAL TREND WILL BE FOR
THE WAVE TO OPEN UP AND LIFT NORTHEAST PASSING MAINLY NORTH OF US
FOR DAYS 6 AND 7. ACTIVE TROPICS AND PARADE OF TROPICAL STORMS INTO
THE SOUTH MAY ALSO STALL PATTERN SOMEWHAT OR KEEP TROUGH EVEN
FURTHER NORTHWEST OF THE AREA SO SOME UNCERTAINTY. SMALL POPS IN
LATER PERIOD SEEM REASONABLE FOR THIS SCENARIO.

&&

.AVIATION...

LINE OF STORMS TO WORK EAST OF THE TAF SITES THROUGH 09Z...WITH
SCATTERED SHRA/ISOLD STORMS LIKELY TO BE A THREAT TO AVIATION
THROUGH THE MORNING AT KRST...AND INTO THE AFTERNOON AT KLSE.
PROBABLY THE BIGGEST CONCERN WILL LIE IN THE MORNING HOURS AT BOTH
SITES WITH THE LOW CLOUDS/MIST HANGING AROUND AFTER THE RAIN ENDS.
UPSTREAM OBSERVATIONS AND SATELLITE DATA SHOWING STRATUS DEVELOPING
WITH IFR CAPABILITIES. THIS AHEAD OF THE COLD FRONT WHERE WEAK
CONVERGENCE AND BOUNDARY LAYER MOISTURE IS MAXIMIZED. CURRENT TAFS
CARRY MVFR CEILINGS AND/OR VSBYS THROUGH THE MORNING...AND WILL
MONITOR THE NEED FOR IFR CONDITIONS BASED ON HOW EXPANSIVE UPSTREAM
STRATUS FIELD BECOMES. WOULD EXPECT ANY VIGOROUS THUNDERSTORM
ACTIVITY TODAY TO REMAIN SOUTH/EAST OF THE TAF SITES. AS THE
AFTERNOON WEARS ON...FRONTAL PASSAGE WILL BRING SHIFT TO NWLY WINDS
AND MUCH DRIER AIRMASS...WITH CEILINGS LIFTING/SCATTERING OUT
QUICKLY. VFR CONDITIONS EXPECTED THROUGH TONIGHT INTO MUCH OF THE
REST OF THE WEEKEND WITH HIGH PRESSURE BUILDING IN. MAY NEED TO
WATCH VALLEY FOG POTENTIAL AT KLSE INTO THE WEEKEND.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...SHEA
AVIATION..........SEB

000
FXUS63 KGRB 280913
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
413 AM CDT THU AUG 28 2008

.SHORT TERM...TODAY THROUGH FRIDAY. SHOWERS AND THUNDERSTORMS
MOVING THROUGH THE REGION EARLY TODAY AS STRONG LOW LEVEL JET
BRINGS UP MOISTURE AHEAD OF WEAK FRONT. THINK THAT SEVERE WEATHER
THREAT WILL BE HAMPERED BY RESIDUAL CLOUDS AND RAIN TODAY...BUT IF
WE GET SUNSHINE LATER IN THE DAY THERE COULD BE A FEW STORMS WITH
GUSTY WINDS. DRIER AIR ARRIVES TONIGHT WITH WARM...DRY WEATHER
EXPECTED FRIDAY.

.LONG TERM...FRI NGT THRU NXT WED. MAIN FCST FOCUS THRU THE
UPCOMING HOLIDAY WEEKEND WL BE TEMPS AS QUIET WEATHER PATN TO
PREVAIL OVR THE RGN THANKS TO HI PRES. FCST BECOMES MORE
CHALLENGING TOWARD THE MIDDLE OF NXT WEEK AS AN UPR TROF AND
ASSOCIATED CDFNT APPROACH WI.

A BROAD AREA OF HI PRES TO EXTEND FROM THE MIDWEST INTO THE GREAT
LKS RGN FRI NGT AND SHOULD PROVIDE FOR MOSTLY CLR TO PARTLY CLDY
SKIES WITH A RELATIVELY LGT W-SW WND. NOT MUCH CHG IN AIRMASS
ALOFT...THUS WOULD EXPECT MIN TEMPS TO BE CLOSE TO VALUES
WITNESSED THU NGT. A FEW OF THE MDLS WANT TO DROP A WEAK SFC TROF
SWD INTO WI ON SAT...BUT WITH SUCH A DRY AIRMASS IN PLACE...DON`T
SEE MUCH MORE THAN A FEW CLDS FROM THIS FEATURE (ASSUMING IT EVEN
EXISTS). OTHERWISE...HI PRES REMAINS OVR THE GREAT LKS THRU 00Z
SUNDAY. A TOUCH OF WAA WL ALLOW TEMPS TO RISE BACK INTO THE UPR
70S TO LWR 80S FOR SAT.

A NEW UPR TROF DIGS INTO THE PAC NW SAT NGT WHICH ALLOWS FOR
DOWNSTREAM UPR RIDGING TO TAKE PLACE OVR THE MIDWEST/WRN GREAT
LKS. MAY NEED TO NUDGE MIN TEMPS UP A COUPLE OF DEGS OVR SRN
SECTIONS OF THE FCST AREA AS TEMPS ALOFT CONT TO SLOWLY WARM.
WHILE THE UPR TROF MOVS INLAND TOWARD THE ROCKIES ON SUNDAY...THE
UPR RDG REMAINS PARKED OVR THE GREAT LKS. WNDS ARE EXPECTED TO
BECOME MORE FROM A S-SE DIRECTION...THUS INLAND LOCATIONS WL SEE
WARMER TEMPS WITH READINGS IN THE LWR TO MID 80S. THIS WOULD PUT
TEMPS ABT 10 DEGS ABV NORMAL FOR THE LAST DAY OF AUGUST.

TRANQUIL WEATHER TO PERSIST OVR NE WI TO START THE WORK WEEK WITH
THE UPR TROF OVR THE ROCKIES AND THE UPR RDG OVR THE ERN CONUS.
MEAN FLOW ALOFT WL BE FROM THE SW FOR WI ON MON WHICH IS EXPECTED
TO NOT ONLY BRING WARM TEMPS...BUT A GRADUAL INCREASE IN LOW LVL
MSTR. 8H TEMPS RESIDING IN THE UPR TEENS SHOULD SEND SFC TEMPS
INTO THE MID 80S (EXCEPT RIGHT ALONG THE LAKE AND BAY).

MDLS APR TO BE TRYING TO GET INTO BETTER SYNC WITH THE HANDLING OF
THE UPR TROF TOWARD THE MIDDLE OF NXT WEEK. THE WILD CARD COULD BE
WHERE TROPICAL SYSTEM `GUSTAV` WL BE LOCATED AND WHETHER IT WL
HAVE ANY IMPACT ON THE SPD WITH WHICH SYSTEMS TRAVERSE THE CONUS.
IT APRS THAT THE ERN CONUS UPR RDG WL BE MORE OF A FACTOR ON THE
APPROACHING UPR TROF (BY SLOWING IT DOWN). IF THIS TREND CONTS...
LTR SHIFTS MAY BE ABLE TO GO COMPLETELY DRY OVR NE WI ON TUE AND
FOCUS MORE ON THE TUE NGT OR WED TIME FRAME FOR OUR NXT CHC OF
SHWRS AND TSTMS.
&&

.AVIATION...THUNDERSTORMS WITH MVFR CIGS AND VSBYS EXPECTED
THROUGH EARLY AFTERNOON. THEN VFR/MVFR WEATHER EXPECTED LATER IN THE DAY
WITH SCATTERED THUNDERSTORMS. HAZE WILL LIKELY BE COMMON THIS
AFTERNOON WITH VSBYS AROUND 5 MILES. WILL BECOME VFR OVERNIGHT AND
FRIDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
RDM/KALLAS

000
FXUS63 KMKX 280913
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
413 AM CDT THU AUG 28 2008

.SHORT TERM...30-40 KT LLJ IS SHIFTING EWD INTO WI ALONG WITH
ASSOCIATED LOWER TROPOSPHERIC WAA...THETAE...AND FRONTOGENESIS.
LLJ IS PROGGED TO WEAKEN THIS AM BUT CURRENT MCS WILL PROBABLY
BRING RAIN TO ALL OF AREA BEFORE WEAKENING AND BECOMING MORE SCT.
EXPECT CONVECTION TO REDEVELOP THIS AFTERNOON AS SRN PERIPHERY OF
UPPER TROUGH AXIS CURRENTLY OVER THE NRN PLAINS APPROACHES THE
REGION ALONG WITH ITS WEAK COLD FRONT. SOME SUNSHINE BY AFTERNOON
AND PWS APPROACHING 2 INCHES SHOULD CONTRIBUTE TO MUCAPE VALUES
FROM 1000 TO 1500 J/KG. CAPPING SHOULD REMAIN WEAK AND LIFT SHOULD
BE SUFFICIENT FOR DECENT COVERAGE OF CONVECTION LATER THIS
AFTERNOON AND INTO THE EVENING. DESPITE WEAK LAPSE RATES...DEEP
SHEAR OF 35-40 KTS COMBINED WITH THE AFOREMENTIONED CAPE COULD
RESULT IN A FEW SEVERE STORMS ALONG WITH HEAVY RAINFALL.

COLD ADVECTION TO QUICKLY DRY OUT ATM LATER THIS EVENING BUT NOT
MUCH OVERALL COOLING EXPECTED AS UPPER TROUGH AND COOLER AIR LIFTS
NEWD INTO CANADA. HIGH PRESSURE TO PREVAIL FRIDAY AND THE WEEKEND
WITH 1000-500 MB THICKNESSES OF 570-576 DM AND HIGH TEMPS IN LOWER
80S. IN THE UPPER ATM...A HIGH AMPLITUDE RIDGE WILL BUILD OVER
THE CENTRAL USA DURING THIS PERIOD.


.LONG TERM...
THE UPPER RIDGE WILL SLOWLY MOVE EWD WITH A SERIES OF UPPER
TROUGHS OVER THE WRN USA LIFTING NEWD THROUGH THE PLAINS AND INTO
CANADA. DECAYING COLD FRONTS MAY PROGRESS FAR ENOUGH EAST SO SMALL
CHANCES OF RAIN ARE FCST DURING THE WEEK.


&&

.AVIATION...
AREA OF WEAKENING THUNDERSTORMS PUSHING INTO SOUTH CENTRAL
WISCONSIN.  LOCAL MODELS HAVE THIS AREA PUSHING ACROSS ALL OF SOUTH
CENTRAL AND MUCH OF SOUTHEAST WISCONSIN BEFORE DIMINISHING.  MORE
THUNDERSTORMS EXPECTED THIS AFTERNOON AND EARLY EVENING ALONG COLD
FRONT. SOME MVFR CIGS POSSIBLE SOUTH CENTRAL THIS MORNING IN
PRECIPITATION...AND AGAIN THIS AFTERNOON WITH ANY THUNDERSTORMS.

PATCHY LIFR FOG OVER SOUTHEAST WISCONSIN EARLY THIS MORNING.
VISIBILITIES EXPECTED TO IMPROVE TO MAINLY MVFR BY 13Z AS HIGH
CLOUDS INCREASE.

&&

.MARINE...
AS SOUTHEAST WINDS INCREASE...WAVES EXPECTED TO BUILD BUT REMAIN
BELOW SMALL CRAFT CRITERIA.  WEAKENING THUNDERSTORMS MAY REACH LAKE
MICHIGAN THIS MORNING...THEN STRONGER THUNDERSTORMS POSSIBLE THIS
AFTERNOON AND EARLY EVENING WITH COLD FRONT.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

SHORT/LONG TERM...20
AVIATION/MARINE...06

000
FXUS63 KARX 280735
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
234 AM CDT THU AUG 28 2008

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

FORECAST CHALLENGE IS IN FIRST 15 HOURS AS NORTHERN FLOW SHORT WAVE
TROUGH ENERGY MOVES THROUGH TODAY WITH CONVECTIVE THREAT. AFTER THAT
IT LOOKS LIKE A QUIET HOLIDAY WEEKEND ON TAP.

FAIRLY POTENT SHORT WAVE TROUGH IS MOVING ALONG THE CANADIAN AND
NORTH DAKOTA BORDER EARLY THIS MORNING. MID/UPPER LEVEL JET CRASHING
OUT OF THE NORTHERN ROCKIES INTO THE DAKOTAS THIS MORNING HAS SET UP
STRONG LOW LEVEL FLOW IN RESPONSE WITH 55 KTS AROUND 850 MB ON OAX
VAD WIND PROFILE AS OF 06Z. THIS HAS GENERATED QUITE A BIT OF
CONVECTION OVERNIGHT WITH MUCAPES STILL IN 500 TO 1000 J/KG RANGE
MAINLY WEST OF MISSISSIPPI RIVER. BASED ON LAPS SOUNDINGS APPEARS
ELEVATED CONVECTION IS DEVELOPING AROUND 800 MB SO MAIN THREAT IS
SOME HAIL AND ACTUALLY STORMS HAVE BEEN WEAKENING AS THEY SHIFT
EAST...EVEN WITH DECENT DYNAMIC FORCING FOR LATE AUGUST. MUCH NEEDED
RAINFALL WILL PROBABLY STAY UNDER AN INCH FOR NEARLY EVERYONE.

AS SHORT WAVE ENERGY CONTINUES EAST...STRONGER SURFACE FRONT OVER
NORTHERN PLAINS WILL LIKELY MERGE WITH NEARBY QUASI-STATIONARY
BOUNDARY AND THEN MOVE EAST THIS AFTERNOON. SHORT TERM MODEL
GUIDANCE SUPPORTS THIS AND GIVEN PROGRESSIVE NATURE WOULD AGREE THAT
MAIN RAIN THREAT WILL BE THIS MORNING. HAVE ALREADY DROPPED RAIN
THREAT FOR MOST AREAS THIS EVENING AND LEFT CENTRAL AND SOUTHWEST
WISCONSIN COUNTIES IN FOR JUST EARLY EVENING HOURS BEFORE RETURN TO
DRY SPELL.

AFTER THAT HEIGHTS START TO RISE AND RIDGE BUILDS ACROSS CENTRAL
U.S. FOR WHAT LOOKS LIKE QUIET SEVERAL DAYS. SURFACE RIDGE SETTLES
IN FOR SEASONAL TEMPERATURES AND DRY AIRMASS. GIVEN THIS AND
CLIMATOLOGICAL FAVORED TIME OF YEAR...RIVER VALLEY FOG POSSIBLE A
FEW MORNINGS IN THERE AS WELL.

.LONG TERM...SUNDAY THROUGH WEDNESDAY

UPPER TROUGH THAT DEVELOPS ACROSS PACIFIC NORTHWEST THIS WEEKEND
PROGGED TO EJECT EAST EARLY NEXT WEEK BUT SUBTLE DIFFERENCES IN
MEDIUM RANGE GUIDANCE ON TRACK OF TROUGH. GENERAL TREND WILL BE FOR
THE WAVE TO OPEN UP AND LIFT NORTHEAST PASSING MAINLY NORTH OF US
FOR DAYS 6 AND 7. ACTIVE TROPICS AND PARADE OF TROPICAL STORMS INTO
THE SOUTH MAY ALSO STALL PATTERN SOMEWHAT OR KEEP TROUGH EVEN
FURTHER NORTHWEST OF THE AREA SO SOME UNCERTAINTY. SMALL POPS IN
LATER PERIOD SEEM REASONABLE FOR THIS SCENARIO.

&&

.AVIATION...

LINE OF STORMS TO WORK EAST OF THE TAF SITES THROUGH 09Z...WITH
SCATTERED SHRA/ISOLD STORMS LIKELY TO BE A THREAT TO AVIATION
THROUGH THE MORNING AT KRST...AND INTO THE AFTERNOON AT KLSE.
PROBABLY THE BIGGEST CONCERN WILL LIE IN THE MORNING HOURS AT BOTH
SITES WITH THE LOW CLOUDS/MIST HANGING AROUND AFTER THE RAIN ENDS.
UPSTREAM OBSERVATIONS AND SATELLITE DATA SHOWING STRATUS DEVELOPING
WITH IFR CAPABILITIES. THIS AHEAD OF THE COLD FRONT WHERE WEAK
CONVERGENCE AND BOUNDARY LAYER MOISTURE IS MAXIMIZED. CURRENT TAFS
CARRY MVFR CEILINGS AND/OR VSBYS THROUGH THE MORNING...AND WILL
MONITOR THE NEED FOR IFR CONDITIONS BASED ON HOW EXPANSIVE UPSTREAM
STRATUS FIELD BECOMES. WOULD EXPECT ANY VIGOROUS THUNDERSTORM
ACTIVITY TODAY TO REMAIN SOUTH/EAST OF THE TAF SITES. AS THE
AFTERNOON WEARS ON...FRONTAL PASSAGE WILL BRING SHIFT TO NWLY WINDS
AND MUCH DRIER AIRMASS...WITH CEILINGS LIFTING/SCATTERING OUT
QUICKLY. VFR CONDITIONS EXPECTED THROUGH TONIGHT INTO MUCH OF THE
REST OF THE WEEKEND WITH HIGH PRESSURE BUILDING IN. MAY NEED TO
WATCH VALLEY FOG POTENTIAL AT KLSE INTO THE WEEKEND.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...SHEA
AVIATION..........SEB

000
FXUS63 KARX 280055
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
755 PM CDT WED AUG 27 2008

.UPDATE...RADAR COMPOSITE THIS EVENING INDICATED CONVECTION
INCREASING IN AREAL COVERAGE ACROSS MN AND MOVING INTO NORTHWEST
WI. THIS WAS DUE TO STRENGTHENING LOW LEVEL MOISTURE TRANSPORT...
ALONG WITH UPPER LEVEL DIVERGENCE ASSOCIATED WITH NOSE OF 300MB
JET ADVANCING INTO NORTHERN PLAINS. LAPS SOUNDING INDICATED
CONVECTION WAS ELEVATED AND THIS WAS SUPPORTED BY TAMDAR
SOUNDINGS.

DURING REST OF EVENING...WOULD EXPECT CONVECTION TO CONTINUE
EXPANDING IN COVERAGE AND PRIMARILY AFFECT NORTH AND WEST SECTIONS
OF OUR FORECAST AREA. SMALL HAIL AND GUSTY WINDS EXPECTED WITH
STRONGER STORMS...ALTHOUGH AN ISOLATED SEVERE HAIL REPORT NOT OUT
OF THE QUESTION THIS EVENING.

CURRENT FORECAST IN PRETTY GOOD SHAPE AND ONLY CHANGES EXPECTED
WOULD BE TO UPDATE FOR LATEST TRENDS IN EVOLUTION OF PRECIPITATION
COVERAGE.

&&

.PREV DISCUSSION... /ISSUED 255 PM CDT WED AUG 27 2008/

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT

FORECAST CONCERNS THIS PACKAGE...RAIN CHANCES TONIGHT INTO THU
NIGHT...TEMPERATURES THROUGH THE PERIOD.

DATA ANALYSIS AT 18Z HAD THE FRONTAL BOUNDARY FROM NORTH CENTRAL MN
TO NEAR KFSD TO A LOW IN THE OK PANHANDLE. FRONT HAS MOVED LITTLE
SINCE 12Z THIS MORNING. 850-700MB MOISTURE TRANSPORT AND WEAK
ISENTROPIC LIFT CONTINUED ACROSS MUCH OF MN/IA/WESTERN WI AHEAD OF
THE FRONT. HOWEVER MID LEVEL THETA-E CONVERGENCE THAT WAS FORCING
THE CONVECTION FROM EASTERN MN TO CENTRAL IA THIS MORNING HAD
DIMINISHED...WITH REMNANT -SHRA OVER THE WEST END OF THE FORECAST
AREA CONTINUING TO DECREASE. AN INCREASE OF THE 850MB JET AND SOME
THETA-E CONVERGENCE INTO SOUTHWEST MN/NORTHWEST IA RESPONSIBLE FOR
SCT SHRA/TSRA THERE. CLOUD COVER ACROSS MUCH OF THE REGION AHEAD OF
THE FRONT HOLDING TEMPS DOWN EARLY THIS AFTERNOON.

NO MAJOR ERRORS NOTED WITH 27.12Z NAM/GFS INITIALIZATIONS...THOUGH
GFS WITH THE BETTER FIT TO 700-300MB RA-OBS HGTS ACROSS THE CONUS.
THIS WOULD LEAN TOWARD FAVORING GFS...BUT GFS LOOKS TO SUFFER
CONVECTIVE FEEDBACK OVER SOUTHERN MN THIS EVENING WITH A 50 UNIT
VORTICITY MAXIMA NEAR KMSP AT 06Z. DESPITE THIS...NAM/GFS SOLUTIONS
QUITE SIMILAR THIS CYCLE. DPROG/DT OF 500MB HGTS AT 27.12Z SHOWED
THE GFS RUNS OF 25.12Z AND 26.12Z VERIFIED BETTER ACROSS THE
NORTHERN CONUS/SOUTHERN CAN. THRU 36HRS TREND IS A BIT SLOWER/
STRONGER WITH THE TROUGH MOVING INTO THE UPPER MIDWEST. FOR 36-60HRS
TREND IS STRONGER WITH THE LEAD PIECE OF ENERGY AS IT LIFTS INTO
ONT/QUE AND WEAKER WITH A SECONDARY WAVE INTO MAN/WESTERN ONT. FOR
60-84HRS MODEL CONSENSUS INCREASED FOR RIDGING TO BUILD FROM MAN
TO THE MID MS VALLEY. THESE TRENDS GET GOOD SUPPORT FROM ECMWF/UKMET
AND GFS ENSEMBLE MEAN. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED
NAM/GFS REASONABLE WITH THE SFC MASS FIELDS. NEITHER MODEL DID ALL
THAT WELL WITH THE 12Z-18Z PRECIP ACROSS THE REGION. PER WV
IMAGERY...BOTH MODELS APPEAR REASONABLE WITH THE SHORTWAVE DETAILS
ACROSS NOAM/EASTERN PAC WITH PERHAPS A SLIGHT EDGE TO GFS ON THE
ENERGY OVER BC DROPPING INTO MT. NO CLEAR MODEL FAVORITE AT THIS
TIME AND WILL FAVOR A MODEL BLEND/COMPROMISE. FORECAST CONFIDENCE IN
THE AVERAGE TO GOOD RANGE THIS CYCLE.

FOR TONIGHT...LOW LEVEL JET STRENGTHENS INTO THE AREA AS THE SFC-MID
LEVEL TROUGH DEEPENS IN THE NORTHERN PLAINS...IN RESPONSE TO THE
NORTHERN ROCKIES TROUGH DIGGING INTO THE NORTHERN PLAINS. MOISTURE
TRANSPORT/THETA-E CONVERGENCE INCREASE INTO THE AREA THRU THE
NIGHT...WITH INCREASING 850-700MB FN CONVERGENCE JUST NORTHWEST OF
THE FORECAST AREA. P-WATS INCREASE TO AROUND 1.75 INCHES. THIS WITH
MOST UNSTABLE/ELEVATED CAPES OF 1K TO 1.5K J/KG IN THE INFLOW
AIRMASS TONIGHT. LEAD PIECES OF SHORTWAVE ENERGY THRU THE TROUGH
PROVIDE SOME PV ADVECTION/LIFT BY 06Z...MAINLY NORTHWEST OF THE
FORECAST AREA. AREA ALSO CLIPPED BY AGEOSTROPHIC FLOW/DIVERGENCE
ALOFT ASSOCIATED WITH A 110KT 300MB JET MAX. STRONGER FORCING OF LOW
LEVEL CONVERGENCE AND UPPER LEVEL DIVERGENCE POINT TO CONVECTION
DEVELOPING NEAR A KMSP-KOMA LINE THIS EVENING. CONVECTION THEN
DEVELOPS/TRANSLATES INTO NORTHWEST WI FOLLOWING STRONGER UPPER LEVEL
DIVERGENCE...WHILE LOWER LEVEL THERMODYNAMICS/CONVERGENCE SLOWLY
TRANSLATE TO THE SOUTHEAST WITH THE SFC-700MB TROUGH AXIS. THIS
LOWER LEVEL FORCING/CONVERGENCE THEN CONTINUES TO SLOWLY TRANSLATE
SOUTHEAST ACROSS THE FORECAST AREA THU MORNING INTO THU AFTERNOON...
AS AREA COMES UNDER THE RIGHT ENTRANCE REGION OF A 100-110KT JET
MAX. THUS...INCREASED SHRA/TSRA CHANCE THRU THE EVENING AND TO
LIKELY FOR MUCH OF THE AREA LATER TONIGHT/THU MORNING. LINGERED SOME
LIKELY POPS OVER THE SOUTHEAST END OF THE FORECAST AREA...CHANCE
ELSEWHERE THU AFTERNOON. GIVEN THE STRENGTH OF THE FORCING AND P-WAT
VALUES...POTENTIAL FOR SOME LOCALLY HEAVY RAINS OF 1 TO 2 INCHES
TONIGHT THRU THU. GIVEN THE GENERALLY DRY CONDITIONS ACROSS THE
FORECAST AREA...THESE RAINS LIKELY WELCOMED MOST AREAS WITH MINIMAL
HYDRO/RUNOFF CONCERNS. GIVEN THE STRENGTH OF THE FORCING/LIFT...THE
MOST UNSTABLE /MU/ CAPES AND INCREASING 0-6KM SHEAR TONIGHT...CANNOT
RULE OUT ISOLATED SEVERE STORM TONIGHT. WITH ELEVATED NATURE OF
TSRA...THE SEVERE THREAT WOULD BE HAIL. MU CAPES PROGGED INTO THE 1K
TO 2K J/KG RANGE THU AFTERNOON. HOWEVER...ONGOING CONVECTION/
CONVECTIVE DEBRIS CLOUDS LIKELY TO HAVE STRONG IMPACTS ON THIS.
CANNOT RULE OUT ISOLATED SEVERE TSRA...AGAIN MAINLY A HAIL THREAT...
THU AFTERNOON.

HIGH PRESSURE...DRIER AIR...BUILDING HGTS/RIDGING ALOFT THEN BUILD
ACROSS THE AREA STARTING THU NIGHT AND CONTINUING INTO SAT NIGHT. A
DRY...QUIET PERIOD OF WEATHER EXPECTED THU NIGHT THRU SAT NIGHT...
AFTER A LINGERING SMALL -SHRA/-TSRA CHANCE THU EVENING. MAY YET
NEED VALLEY FOG MENTION LATE FRI NIGHT/EARLY SAT MORNING AS CENTER
OF THE SFC HIGH DRIFTS ACROSS THE AREA. PLENTY OF TIME BETWEEN NOW
AND THEN TO ADD THESE DETAILS IF NEEDED.

WITH CLOUDS AND SOME SOUTH WINDS TONIGHT TRENDED TOWARD WARMER OF
GUIDANCE LOWS. TRENDED TOWARD A BLEND OF GUIDANCE HIGHS THU...WHICH
BLENDS WELL WITH NEIGHBORING GRIDS FOR NOW. HOWEVER WITH CLOUDS/
CONVECTION IN THE AREA...THESE MAY BE TOO WARM...MUCH LIKE TODAY.
FAVORED WARMER OF GUIDANCE LOWS THU NIGHT. GUIDANCE HIGHS/LOWS FOR
FRI/FRI NIGHT SIMILAR AND REASONABLE. FAVORED A BLEND OF GFS MEX/
ENSEMBLE MOS AND HPC GUIDANCE FOR HIGHS/LOWS SAT/SAT NIGHT.

LONG TERM...SUNDAY THROUGH WEDNESDAY

27.00Z MEDIUM RANGE MODELS IN REASONABLY GOOD AGREEMENT WITH EACH
OTHER AND THEIR PREVIOUS RUNS IN THE THE SUN/MON PERIOD...WITH
RIDGING ALOFT OVER THE UPPER MIDWEST AND TROUGHING OVER THE
WESTERN CONUS. TIMING DIFFERENCES DEVELOP FOR TUE/WED AS THE WESTERN
TROUGHING PROGRESSES EAST...GFS/UKMET FASTER...CAN GEM/ECMWF SLOWER.
MODEL RUN-TO-RUN CONSISTENCY SUFFERS AS WELL...BUT THE LESSER RUN-
TO-RUN CONSISTENCY IN THE DAY 6/7 TIME-FRAME HAS BEEN THE TREND MUCH
THE SUMMER. TREND DOES APPEAR STRONGER WITH SOME FORM OF THE TROUGH
PUSHING ACROSS THE REGION TUE/WED. FORECAST CONFIDENCE GOOD SUN/MON
THEN LOWER TUE/WED...ESPECIALLY WITH ANY TIMING DETAILS. RIDGING
ALOFT AND HIGH PRESSURE AT THE SFC TO DOMINATE THE AREA FOR THE
HOLIDAY WEEKEND...WITH DRY/QUIET/WARM WEATHER. THE APPROACHING/
PASSING TROUGH DRIVES A COLD FRONT INTO/ACROSS THE REGION TUE/WED.
SOME MOISTURE RETURN/ADVECTION AHEAD OF THIS FRONT...BUT PLENTY OF
UNCERTAINTY HERE WITH TROPICAL SYSTEM GUSTAV EXPECTED TO BE
APPROACHING THE LA/TX GULF COAST AND IMPACTING FLOW OF MOISTURE
NORTHWARD. WITH THE TIMING DIFFERENCES IN THE TROUGH/FRONTAL PASSAGE
SMALL -SHRA/TSRA CHANCE FROM MON NIGHT THRU WED...PER HPC
GUIDANCE...REASONABLE FOR NOW. WARMING 850-700MB TEMPS UNDER THE
RIDGING ALOFT ALONG WITH RATHER DRY AIRMASS/SUNSHINE/DEEP MIXING
LOOK TO ALLOW FOR ABOVE NORMAL TEMPERATURES THRU THE HOLIDAY
WEEKEND. GENERALLY USED A BLEND OF GFS MEX/ENSEMBLE MOS AND HPC
GUIDANCE FOR HIGHS/LOWS THRU THE PERIOD.

&&

AVIATION...TONIGHT AND THURSDAY

MAIN FOCUS FOR AVIATION WILL BE RAIN/THUNDERSTORM CONCERNS MAINLY
TONIGHT INTO THURSDAY. A COLD FRONT OVER WESTERN MINNESOTA WILL
TRACK EAST INTO EASTERN WISCONSIN BY 00Z FRIDAY. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP ALONG AND AHEAD OF THE COLD FRONT THIS
EVENING AND MOVE EAST INTO BOTH KRST AND LSE BY 03Z AND 05Z
THURSDAY. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ALONG THE
FRONT THURSDAY. THIS WILL PROVIDE THE CONTINUATION OF SHOWERS AND
THUNDERSTORMS AT BOTH TAF SITES. CONFIDENCE IS HIGH FOR SHOWERS AND
THUNDERSTORMS TO CONTINUE INTO THURSDAY...THOUGH CONFIDENCE IS LOW
ON EXACT TIMING OF SHOWERS AND EMBEDDED THUNDERSTORMS. BASED ON THIS
HAVE INTRODUCED VICINITY OF SHOWERS AND CB AT BOTH KRST AND KLSE AT
10Z AND 12Z THURSDAY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...RRS
AVIATION..........DTJ

000
FXUS63 KGRB 272024
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
324 PM CDT WED AUG 27 2008

.SHORT TERM...TONIGHT AND THURSDAY

QUESTION OF FORECAST IS PCPN CHANCES WITH PASSAGE OF COLD FRONT
CURRENTLY OVER NORTHEAST MN. FRONT MOVING SLOWLY EAST AS UPPER
FLOW PARALLEL TO FRONT. FRONTAL PASSAGE EXPECTED THU
AFTN/EVE...DRIVEN EAST BY SHORT WAVE NOW MOVING THROUGH HIGH
PLAINS.

MODELS HIGHLIGHT TSTM COMPLEX TO FORM THIS EVENING...SOUTHERN
MN/NORTHERN IA AS STRENGTHENING LLVL JET FOCUSED INTO THAT AREA.
EXPECT COMPLEX TO SHIFT EAST OVERNIGHT/EARLY MORNING...WEAKENING AS
MOVES INTO MORE STABLE REGION AND FORCING FROM LLVL JET WEAKENS.
EXPECT ADDITIONAL SHOWERS/STORMS TO FORM WITH FRONT DURING DAY ON
THU...AIDED BY RRQ OF JET LIFTING INTO LAKE SUPERIOR REGION. HAVE
TRIED TO SHOW SOME RESOLUTION OF TWO PCPN EVENTS IN GRIDS.

HAVE BACKED OFF SOME ON TSTM WORDING AS INSTABILITY VERY LIMITED.
TEMPERATURES TO BE VERY DEPENDENT ON AMOUNT OF CLOUDINESS...
ESPECIALLY GIVEN WIDESPREAD LOWER CLOUDS CURRENTLY ALONG FRONT.
MADE LITTLE CHANGE TO PREVIOUS FORECAST...THOUGH LATER SHIFTS MAY
WANT TO DROP THEM A BIT.

.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY.

THE MAIN FORECAST CONCERN DURING THIS PERIOD IS PRECIPITATION
TIMING. SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY EVENING AS
A 500MB TROUGH AND SURFACE FRONT PUSH THROUGH NORTHEAST WISCONSIN.
BUT IT APPEARS THAT THE ACTIVITY WILL BE OUT OF MOST OF THE AREA
BY 06Z SO HAVE ONLY LEFT SLIGHT CHANCE POPS IN THE EAST 06Z TO
12Z. MEDIUM RANGE MODELS THEN SHOWED A LOW AMPLITUDE RIDGE AND SURFACE
HIGH PRESSURE SLOWLY MAKING THEIR WAY ACROSS THE REGION THROUGH
EARLY NEXT WEEK. SO FAR IT WOULD SEEM THAT TUESDAY IS THE BEST BET
FOR THE ONSET OF PRECIPITATION ASSOCIATED WITH THE NEXT SHORT WAVE
AND COLD FRONT. HAVE CHANCE POPS GOING FOR CENTRAL WISCONSIN BUT
ONLY SLIGHT CHANCE FOR MOST OF THE REST OF THE FORECAST AREA. THE CHANCE
POPS WERE EXPANDED TO COVER ALL BUT THE FOX VALLEY AND LAKESHORE ON
TUESDAY NIGHT. WOULD NOT BE SURPRISED TO SEE MODELS BRINGING THE
NEXT SYSTEM INTO THE AREA EVEN SLOWER ON THE NEXT SEVERAL RUNS.

TEMPERATURES SHOULD BE AT OR ABOVE NORMAL IN MOST CASES...THE MAIN
EXCEPTION BEING FRIDAY NIGHT UNDER HIGH PRESSURE.
&&

.AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH 06Z THURSDAY
WITH POTENTIAL FOR MVFR/IFR CONDITIONS THEREAFTER...AS
THUNDERSTORM COMPLEX HEADS EAST FROM MN/IA INTO WI AND WEAKENS.
LIMITED INSTABILITY OVER NORTHEAST WI MAKES ME DOWNPLAY TSTM
ACTIVITY IN TAFS THROUGH 18Z THU...HIGHER CHANCES FOR TSTM AFTER
THAT TIME AS COLD FRONT MOVES THROUGH.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
TE/MG

000
FXUS63 KMKX 272023
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
325 PM CDT WED AUG 27 2008

.DISCUSSION...FORECAST CENTERS ON INCREASING THREAT OF PRECIPITATION
LATER TONIGHT INTO THURSDAY EVENING.  MORNING ACTIVITY ACROSS MN/IA
DIMINISHED AS PLANNED AS IT PUSHED INTO LARGE AREA OF SUBSIDENCE AND
DRIER AIR OVER CENTRAL MS VALLEY.  MCV SHOWING UP IN SOUTHEAST IA
PER LATEST VSBL IMAGERY. PREFER GFS SOLUTION FOR THE SHORT TERM DUE
TO BETTER AGREEMENT IN SYNOPTIC SCALE FEATURES BETWEEN SUCCESSIVE
MODEL RUNS.  LOW LEVEL JET BEGINNING TO INCREASE ACROSS PLAINS AS
WINDS BEGINNING TO VEER AHEAD OF STRONG SHORT WAVE TROUGH IN MT/SRN
CANADA.  700H PROFILERS SHOWING VEERING WINDS IN THE HIGH PLAINS
INDICATING PRECURSOR SHORT WAVE THAT WILL AFFECT WI LATER TNGT AND
THU MRNG.  AHEAD OF THIS WAVE...NOSE OF WEAKER LLJ OF 20 TO 30KTS
PUSHES ACROSS SRN WI WITH A RAPID INCREASE IN PRECIPITABLE WATER OF
ONE HALF INCH.  ELEVATED LIFTED INDEX DROPS TO AROUND ZERO BY 12Z IN
THE WEST BUT MID LEVEL LAPSE RATES STILL ON THE WEAK SIDE.  THINKING
BETWEEN ACTIVITY TO THE WEST SPILLING SOUTHWARD ALONG THICKNESSES
AND LOW LEVEL MOISTURE FLUX CONVERGENCE...SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE EXPECTED.

LINGERING CLOUD COVER WILL ACT TO RETARD HEATING SOMEWHAT IN THE
AFTERNOON AS BEST LOW LEVEL CONVERGENCE MOVES THROUGH...LIMITING
MORE ORGANIZED CONVECTION.  NEVER THE LESS...RIGHT ENTRANCE REGION
OF UPPER JET PASSES ACROSS REGION DURING THE AFTERNOON AND
EVENING...AND FN RESPONSE TO INCREASING LOW TO MID LEVEL 2D FULL
WIND FRONTOGENESIS WORTH NOTING.  HENCE WL GO WITH SCT REDEVELOPMENT
IN THE AFTN SOUTH CENTRAL INCREASING TO NUMEROUS ACTIVITY IN THE
SOUTHEAST DURING THE EVENING. SHORT RANGE ENSEMBLE POPS INCREASES TO
70 PERCENT DURING THE EVENING IN THE SOUTHEAST.

NORTHWEST BREEZES CARRY LESS HUMID AIR ACROSS AREA LATE THU NIGHT
AND FRI WITH LIGHT BOUNDARY LAYER WINDS SETTING UP FOR FRIDAY
NIGHT.  WEAK FRONTAL BOUNDARY TO THE NORTH WITH PATCHY MID LEVEL
CLOUDS BUT WITH LIGHT WINDS AND INCREASE IN LOW LEVEL MOISTURE FROM
RAIN...THINKING FOG A GOOD BET FOR EARLY SATURDAY.  PENDING CLOUD
COVER...MAY BE SOME QUARTER MILE VISIBILITIES.

MORE UNCERTAINTY CREEPING INTO THE EXTENDED FORECAST BEYOND MONDAY
NIGHT.  UNCERTAINTY MAINLY DUE TO TIMING AND TRACK OF GUSTAV AND ITS
AFFECT ON APPROACHING SHORT WAVE TROUGH FOR TUE AND WED.  LATEST
EXTENDED GUIDANCE TAKING A MORE NORTHEASTLY TRACK AND CARRYING
REMAINS OF HURRICANE INTO WESTERN GULF DURING THE PERIOD...WITH A
SECOND TROPICAL DISTURBANCE IN THE WRN ATLANTIC.  GFS TRENDING
SLOWER WITH WEAKENING SHORT WAVE TROUGH INTO THE UPPER MIDWEST
DURING THIS PERIOD...WHILE HI RES ECMWF MUCH WEAKER AND EVEN SLOWER
WITH SURFACE TROUGH...AS HIGH PRESSURE AND SUBSIDENCE REINFORCES
ITSELF ACROSS ERN CONUS.  LITTLE RUN TO RUN CONSISTENCY IN ANY
EXTENDED GUIDANCE AT THIS POINT. MOISTURE REMAINS LOW...HOWEVER LOW
LEVEL INCRG SRLY WNDS DOES RESULT IN A BIT OF ELEVATED INSTABILITY
TUE INTO WED. FOR NOW...WL GO WITH SCHC POPS MOST AREAS TUE INTO WED
NGT PERIOD.  IF CURRENT TRENDS CONTINUE...WL PROBABLY BE ABLE TO
PULL POPS OUT FROM AT LEAST TUE...AND POSSIBLY INTO WED.  GFS
ENSEMBLES SHOWING LOTS OF VARIABILITY IN THE LATER PERIODS...SO
LITTLE STOCK CAN BE PUT IN DGEX EITHER. HPC LEANING ON ECMWF MEAN
WHICH HAS BEST POPS IN LAST PERIODS.

GFS 500MB 5 DAY MEANS SHOW ZONAL FLOW WITH NEAR NORMAL HEIGHTS
ACROSS NRN CONUS TRANSITIONING TO INCREASING HEIGHTS OVER THE
GTLAKES DUE TO UPSTREAM TROFFING ACROSS WEST.  HENCE
WARMER...DAYTIME TEMPERATURES LIKELY...AND MORE SELY BREEZES SHOULD
RESULT IN SLIGHTLY WARMER READINGS ALONG LAKESHORE AS WELL.  DRY
PATTERN TO CONTINUE INTO EARLY SEPTEMBER...PENDING TRACK OF GUSTAV.

&&

.AVIATION...WEAK SURFACE RIDGING AND LIGHT WINDS IN PLACE...WHILE
SCATTERED CU THIS AFTERNOON GIVES WAY TO INCREASING MID TO HIGH
CLOUDS AHEAD OF LOW PRESSURE AREA TO THE NORTHWEST.  SMALL CHANCES
FOR THUNDERSTORMS LATE TONIGHT AND THURS MORNING FOR SOUTHWEST AND
SOUTH-CENTRAL WI..BUT OPTED TO LEAVE OUT OF TAFS FOR NOW.
INCREASING CLOUDS OVERNIGHT SHOULD HINDER ANY FOG DEVELOPMENT.

&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.

$$
SHORT TERM/LONG TERM....MBK
AVIATION................CJK

000
FXUS63 KARX 271955
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
255 PM CDT WED AUG 27 2008

.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT

FORECAST CONCERNS THIS PACKAGE...RAIN CHANCES TONIGHT INTO THU
NIGHT...TEMPERATURES THROUGH THE PERIOD.

DATA ANALYSIS AT 18Z HAD THE FRONTAL BOUNDARY FROM NORTH CENTRAL MN
TO NEAR KFSD TO A LOW IN THE OK PANHANDLE. FRONT HAS MOVED LITTLE
SINCE 12Z THIS MORNING. 850-700MB MOISTURE TRANSPORT AND WEAK
ISENTROPIC LIFT CONTINUED ACROSS MUCH OF MN/IA/WESTERN WI AHEAD OF
THE FRONT. HOWEVER MID LEVEL THETA-E CONVERGENCE THAT WAS FORCING
THE CONVECTION FROM EASTERN MN TO CENTRAL IA THIS MORNING HAD
DIMINISHED...WITH REMNANT -SHRA OVER THE WEST END OF THE FORECAST
AREA CONTINUING TO DECREASE. AN INCREASE OF THE 850MB JET AND SOME
THETA-E CONVERGENCE INTO SOUTHWEST MN/NORTHWEST IA RESPONSIBLE FOR
SCT SHRA/TSRA THERE. CLOUD COVER ACROSS MUCH OF THE REGION AHEAD OF
THE FRONT HOLDING TEMPS DOWN EARLY THIS AFTERNOON.

NO MAJOR ERRORS NOTED WITH 27.12Z NAM/GFS INITIALIZATIONS...THOUGH
GFS WITH THE BETTER FIT TO 700-300MB RA-OBS HGTS ACROSS THE CONUS.
THIS WOULD LEAN TOWARD FAVORING GFS...BUT GFS LOOKS TO SUFFER
CONVECTIVE FEEDBACK OVER SOUTHERN MN THIS EVENING WITH A 50 UNIT
VORTICITY MAXIMA NEAR KMSP AT 06Z. DESPITE THIS...NAM/GFS SOLUTIONS
QUITE SIMILAR THIS CYCLE. DPROG/DT OF 500MB HGTS AT 27.12Z SHOWED
THE GFS RUNS OF 25.12Z AND 26.12Z VERIFIED BETTER ACROSS THE
NORTHERN CONUS/SOUTHERN CAN. THRU 36HRS TREND IS A BIT SLOWER/
STRONGER WITH THE TROUGH MOVING INTO THE UPPER MIDWEST. FOR 36-60HRS
TREND IS STRONGER WITH THE LEAD PIECE OF ENERGY AS IT LIFTS INTO
ONT/QUE AND WEAKER WITH A SECONDARY WAVE INTO MAN/WESTERN ONT. FOR
60-84HRS MODEL CONSENSUS INCREASED FOR RIDGING TO BUILD FROM MAN
TO THE MID MS VALLEY. THESE TRENDS GET GOOD SUPPORT FROM ECMWF/UKMET
AND GFS ENSEMBLE MEAN. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED
NAM/GFS REASONABLE WITH THE SFC MASS FIELDS. NEITHER MODEL DID ALL
THAT WELL WITH THE 12Z-18Z PRECIP ACROSS THE REGION. PER WV
IMAGERY...BOTH MODELS APPEAR REASONABLE WITH THE SHORTWAVE DETAILS
ACROSS NOAM/EASTERN PAC WITH PERHAPS A SLIGHT EDGE TO GFS ON THE
ENERGY OVER BC DROPPING INTO MT. NO CLEAR MODEL FAVORITE AT THIS
TIME AND WILL FAVOR A MODEL BLEND/COMPROMISE. FORECAST CONFIDENCE IN
THE AVERAGE TO GOOD RANGE THIS CYCLE.

FOR TONIGHT...LOW LEVEL JET STRENGTHENS INTO THE AREA AS THE SFC-MID
LEVEL TROUGH DEEPENS IN THE NORTHERN PLAINS...IN RESPONSE TO THE
NORTHERN ROCKIES TROUGH DIGGING INTO THE NORTHERN PLAINS. MOISTURE
TRANSPORT/THETA-E CONVERGENCE INCREASE INTO THE AREA THRU THE
NIGHT...WITH INCREASING 850-700MB FN CONVERGENCE JUST NORTHWEST OF
THE FORECAST AREA. P-WATS INCREASE TO AROUND 1.75 INCHES. THIS WITH
MOST UNSTABLE/ELEVATED CAPES OF 1K TO 1.5K J/KG IN THE INFLOW
AIRMASS TONIGHT. LEAD PIECES OF SHORTWAVE ENERGY THRU THE TROUGH
PROVIDE SOME PV ADVECTION/LIFT BY 06Z...MAINLY NORTHWEST OF THE
FORECAST AREA. AREA ALSO CLIPPED BY AGEOSTROPHIC FLOW/DIVERGENCE
ALOFT ASSOCIATED WITH A 110KT 300MB JET MAX. STRONGER FORCING OF LOW
LEVEL CONVERGENCE AND UPPER LEVEL DIVERGENCE POINT TO CONVECTION
DEVELOPING NEAR A KMSP-KOMA LINE THIS EVENING. CONVECTION THEN
DEVELOPS/TRANSLATES INTO NORTHWEST WI FOLLOWING STRONGER UPPER LEVEL
DIVERGENCE...WHILE LOWER LEVEL THERMODYNAMICS/CONVERGENCE SLOWLY
TRANSLATE TO THE SOUTHEAST WITH THE SFC-700MB TROUGH AXIS. THIS
LOWER LEVEL FORCING/CONVERGENCE THEN CONTINUES TO SLOWLY TRANSLATE
SOUTHEAST ACROSS THE FORECAST AREA THU MORNING INTO THU AFTERNOON...
AS AREA COMES UNDER THE RIGHT ENTRANCE REGION OF A 100-110KT JET
MAX. THUS...INCREASED SHRA/TSRA CHANCE THRU THE EVENING AND TO
LIKELY FOR MUCH OF THE AREA LATER TONIGHT/THU MORNING. LINGERED SOME
LIKELY POPS OVER THE SOUTHEAST END OF THE FORECAST AREA...CHANCE
ELSEWHERE THU AFTERNOON. GIVEN THE STRENGTH OF THE FORCING AND P-WAT
VALUES...POTENTIAL FOR SOME LOCALLY HEAVY RAINS OF 1 TO 2 INCHES
TONIGHT THRU THU. GIVEN THE GENERALLY DRY CONDITIONS ACROSS THE
FORECAST AREA...THESE RAINS LIKELY WELCOMED MOST AREAS WITH MINIMAL
HYDRO/RUNOFF CONCERNS. GIVEN THE STRENGTH OF THE FORCING/LIFT...THE
MOST UNSTABLE /MU/ CAPES AND INCREASING 0-6KM SHEAR TONIGHT...CANNOT
RULE OUT ISOLATED SEVERE STORM TONIGHT. WITH ELEVATED NATURE OF
TSRA...THE SEVERE THREAT WOULD BE HAIL. MU CAPES PROGGED INTO THE 1K
TO 2K J/KG RANGE THU AFTERNOON. HOWEVER...ONGOING CONVECTION/
CONVECTIVE DEBRIS CLOUDS LIKELY TO HAVE STRONG IMPACTS ON THIS.
CANNOT RULE OUT ISOLATED SEVERE TSRA...AGAIN MAINLY A HAIL THREAT...
THU AFTERNOON.

HIGH PRESSURE...DRIER AIR...BUILDING HGTS/RIDGING ALOFT THEN BUILD
ACROSS THE AREA STARTING THU NIGHT AND CONTINUING INTO SAT NIGHT. A
DRY...QUIET PERIOD OF WEATHER EXPECTED THU NIGHT THRU SAT NIGHT...
AFTER A LINGERING SMALL -SHRA/-TSRA CHANCE THU EVENING. MAY YET
NEED VALLEY FOG MENTION LATE FRI NIGHT/EARLY SAT MORNING AS CENTER
OF THE SFC HIGH DRIFTS ACROSS THE AREA. PLENTY OF TIME BETWEEN NOW
AND THEN TO ADD THESE DETAILS IF NEEDED.

WITH CLOUDS AND SOME SOUTH WINDS TONIGHT TRENDED TOWARD WARMER OF
GUIDANCE LOWS. TRENDED TOWARD A BLEND OF GUIDANCE HIGHS THU...WHICH
BLENDS WELL WITH NEIGHBORING GRIDS FOR NOW. HOWEVER WITH CLOUDS/
CONVECTION IN THE AREA...THESE MAY BE TOO WARM...MUCH LIKE TODAY.
FAVORED WARMER OF GUIDANCE LOWS THU NIGHT. GUIDANCE HIGHS/LOWS FOR
FRI/FRI NIGHT SIMILAR AND REASONABLE. FAVORED A BLEND OF GFS MEX/
ENSEMBLE MOS AND HPC GUIDANCE FOR HIGHS/LOWS SAT/SAT NIGHT.

.LONG TERM...SUNDAY THROUGH WEDNESDAY

27.00Z MEDIUM RANGE MODELS IN REASONABLY GOOD AGREEMENT WITH EACH
OTHER AND THEIR PREVIOUS RUNS IN THE THE SUN/MON PERIOD...WITH
RIDGING ALOFT OVER THE UPPER MIDWEST AND TROUGHING OVER THE
WESTERN CONUS. TIMING DIFFERENCES DEVELOP FOR TUE/WED AS THE WESTERN
TROUGHING PROGRESSES EAST...GFS/UKMET FASTER...CAN GEM/ECMWF SLOWER.
MODEL RUN-TO-RUN CONSISTENCY SUFFERS AS WELL...BUT THE LESSER RUN-
TO-RUN CONSISTENCY IN THE DAY 6/7 TIME-FRAME HAS BEEN THE TREND MUCH
THE SUMMER. TREND DOES APPEAR STRONGER WITH SOME FORM OF THE TROUGH
PUSHING ACROSS THE REGION TUE/WED. FORECAST CONFIDENCE GOOD SUN/MON
THEN LOWER TUE/WED...ESPECIALLY WITH ANY TIMING DETAILS. RIDGING
ALOFT AND HIGH PRESSURE AT THE SFC TO DOMINATE THE AREA FOR THE
HOLIDAY WEEKEND...WITH DRY/QUIET/WARM WEATHER. THE APPROACHING/
PASSING TROUGH DRIVES A COLD FRONT INTO/ACROSS THE REGION TUE/WED.
SOME MOISTURE RETURN/ADVECTION AHEAD OF THIS FRONT...BUT PLENTY OF
UNCERTAINTY HERE WITH TROPICAL SYSTEM GUSTAV EXPECTED TO BE
APPROACHING THE LA/TX GULF COAST AND IMPACTING FLOW OF MOISTURE
NORTHWARD. WITH THE TIMING DIFFERENCES IN THE TROUGH/FRONTAL PASSAGE
SMALL -SHRA/TSRA CHANCE FROM MON NIGHT THRU WED...PER HPC
GUIDANCE...REASONABLE FOR NOW. WARMING 850-700MB TEMPS UNDER THE
RIDGING ALOFT ALONG WITH RATHER DRY AIRMASS/SUNSHINE/DEEP MIXING
LOOK TO ALLOW FOR ABOVE NORMAL TEMPERATURES THRU THE HOLIDAY
WEEKEND. GENERALLY USED A BLEND OF GFS MEX/ENSEMBLE MOS AND HPC
GUIDANCE FOR HIGHS/LOWS THRU THE PERIOD.

&&

.AVIATION...TONIGHT AND THURSDAY

MAIN FOCUS FOR AVIATION WILL BE RAIN/THUNDERSTORM CONCERNS MAINLY
TONIGHT INTO THURSDAY. A COLD FRONT OVER WESTERN MINNESOTA WILL
TRACK EAST INTO EASTERN WISCONSIN BY 00Z FRIDAY. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP ALONG AND AHEAD OF THE COLD FRONT THIS
EVENING AND MOVE EAST INTO BOTH KRST AND LSE BY 03Z AND 05Z
THURSDAY. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ALONG THE
FRONT THURSDAY. THIS WILL PROVIDE THE CONTINUATION OF SHOWERS AND
THUNDERSTORMS AT BOTH TAF SITES. CONFIDENCE IS HIGH FOR SHOWERS AND
THUNDERSTORMS TO CONTINUE INTO THURSDAY...THOUGH CONFIDENCE IS LOW
ON EXACT TIMING OF SHOWERS AND EMBEDDED THUNDERSTORMS. BASED ON THIS
HAVE INTRODUCED VICINITY OF SHOWERS AND CB AT BOTH KRST AND KLSE AT
10Z AND 12Z THURSDAY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...RRS
AVIATION..........DTJ