[top]
000
FXUS63 KMKX 082152
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
350 PM CST SUN NOV 8 2009
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MAIN SHORT TERM QUESTION FOCUSES ON DECREASING THREAT OF LIGHT
PRECIPITATION NEXT 36 HOURS. BOTH NAM AND GFS SHOWING LOWER
ATMOSPHERIC MOISTURE AVAILABLE DURING THE PERIOD WITH COLUMN FAILING
TO SATURATE ABV 5K FEET. GUIDANCE IN GOOD AGREEMENT ON SHORT WAVE
TROUGH OVER WRN SODAK WEAKENING AS IT CLIMBS RIDGE INTO WRN GTLAKES
OVERNIGHT WITH SYNOPTIC SCALE FORCING REMAINING NORTH.
EXPECT INCREASING CLOUDS OVERNIGHT TIED TO INCREASING TOTAL COLUMN
CONDENSATE ON NCEP 4KM WRF MODEL WHICH IS NICELY DEPICTING THE
INCREASING UPSTREAM CLOUDS ACROSS THE CENTRAL PLAINS. WARM FRONT
FROM NEAR KDLL TO VCNTY OF KBUU AS LAKE MI PREVENTING SURFACE WARM
FRONT FROM PUSHING NORTH IN ERN CWA. WEB CAMS SHOW AREAS OF HAZE
OVER SHORELINE AS MOIST DEWPOINTS IN THE LOWER 50S ADVECT OVER THE
SLIGHTLY COOLER WATERS OF THE LAKE. SST MODIS IMAGE FROM 16Z
SHOWING LAKE TEMPS AROUND 9-10C. AS WINDS GRADUALLY VEER THROUGH
THE EVENING...EXPECT HAZE TO DECREASE...BUT WINDS WILL REMAIN SELY
AT KSBM FOR A LONGER PERIOD OF TIME. HENCE BETTER CHANCE FOR MORE
SIGNIFICANT FOG IN SHEBOYGAN COUNTY THIS EVENING BEFORE WINDS VEER.
SHORT TERM GUIDANCE IN REASONABLE AGREEMENT ON DEPICTING UPPER LEVEL
FLOW SLIGHTLY MORE PROGRESSIVE AND FLATTER ON MONDAY. ALSO LESS
SATURATION IN THE MID LEVELS SO PULLED POPS FROM MONDAY AS WEAK MID
LEVEL TROUGH PASSES THROUGH. WEAK FORCING FARTHER SOUTH MONDAY
NIGHT AS GREATER SURGE OF DRIER AIR ACROSS SRN WI. HOWEVER...WAS
RELUCTANT TO COMPLETLY PULL POPS AS ENHANCED SYNOPTIC SCALE FORCING
ASSOCIATED WITH RIGHT ENTRANCE REGION STILL PASSES ACROSS FAR
SOUTH. TOOK POPS DOWN TO SCHC IN FAR SOUTH. OTRW LARGE HIGH
PRESSURE AND VERY DRY AIR SETTLES OVER REGION FOR TUE AND WED.
SLIGHT COOLING IN THE LOW LEVELS BUT WITH PLENTY OF
INSOLATION...STILL EXPECTING TEMPS AOA NORMAL.
.LONG TERM/WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGHER CONFIDENCE IN FIRST DAYS OF EXTENDED PERIOD...WITH CONFIDENCE
PLUMMETING TO EXASPERATION LEVELS /LT 20PERCENT/ FOR THE WEEKEND.
LATEST ECMWF MORE IN LINE WITH EARLIER GFS THINKING ON CARRYING
SYSTEM MADE UP OF REMNANTS OF IDA ACROSS SOUTHEAST CONUS AND
GRADUALLY OUT TO SEA. THIS SLOWER PROGRESSION RESULTS IN MORE
PERSISTENT RIDGING AND SUPPRESSION OF DEEPER MOISTURE ACROSS SOUTH
CENTRAL CONUS INTO GTLAKES REGION. HENCE STILL LOOKING GOOD FOR DRY
CONDITIONS FOR THU AND FRI WITH TEMPS STILL AVERAGING ABV NORMAL.
BOTH GFS AND ECMWF HAVING DIFFICULTIES WITH AMPLITUDE AND TIMING OF
EJECTING SHORT WAVE TROUGH INTO THE CENTRAL CONUS OVER THE WEEKEND.
DREADFUL RUN TO RUN CONSISTENCY AND AGREEMENT. GFS ENSEMBLES HAS
INCREASING MEMBER VARIABILITY...BUT MOST MEMBERS STILL SHOW AT LEAST
WEAK MID LEVEL TROF CROSSING WRN GTLAKES LATE IN THE WEEKEND.
AVAILABLE MOISTURE QUESTIONABLE...SO FOR NOW WL SCALE BACK TO SCHC
POPS FOR ENTIRE WEEKEND AND BEGIN TO ADJUST AS LONG TERM GUIDANCE
/HOPEFULLY/ GETS BETTER HANDLE ON SCENARIO.
LARGE POSITIVE 5 DAY 500H MEAN ANOMOLY CURRENTLY OVER GTLAKES AND
CENTRAL CONUS STILL EXPECTED TO WEAKEN EARLY NEXT WEEK AS UPPER FLOW
TRANSITIONS TO FASTER ZONAL PATTERN ACROSS CONUS. THIS IS IN
RESPONSE TO LARGE SCALE DEEP TROFFING AND 300METER NEGATIVE HEIGHT
ANOMOLY THAT FORMS OVER AK AND EVENTUALLY EXTENDS SWD ACROSS WRN CAN
INTO PAC NORTHWEST. THIS PATTERN WILL RESULT IN COLDER...AT LEAST
MORE SEASONAL TEMPERATURES EVENTUALLY ARRIVING...AND POTENTIAL FOR
MORE UNSETTLED CONDITIONS LATE NEXT WEEK INTO HOLIDAY WEEK...AS
EXPECTED AT THIS TIME OF YEAR.
&&
.AVIATION...LOW PRESSURE IN SOUTHERN MINNESOTA WILL LIFT NORTHEAST
OVERNIGHT...DRAGGING A TROUGH ACROSS SOUTHERN WISCONSIN. WIND SHIFT
FROM SW TO NW WILL OCCUR MON MORNING BETWEEN 14Z AND 18Z.
LOW LEVEL MOISTURE AHEAD OF THE TROUGH TONIGHT INTO MONDAY MORNING
COULD PRODUCE MVFR STRATUS DECK AND MVFR FOG...ESPECIALLY AFTER
MIDNIGHT TONIGHT. HANDLED POSSIBILITY IN TAFS WITH SCT CLOUDS
MENTION. NW WINDS WILL DIE DOWN QUICKLY BEHIND THE TROUGH MON
AFTERNOON AND EITHER HIGH CLOUDS OR CLEAR SKIES WILL PREVAIL THROUGH
WED UNDER HIGH PRESSURE.
&&
.MARINE...QUIET MARINE WEATHER WITH LIGHT WINDS TONIGHT. WILL HAVE
TO WATCH LIGHT SOUTHEAST FLOW REGIME LATE THIS EVENING AND OVERNIGHT
FOR POSSIBLE ADVECTION FOG BUT RISK LEVEL MARGINAL TO INCLUDE IN NSH
FCST.
NORTH-NORTHEAST WINDS PICK UP LATE MONDAY NIGHT INTO TUESDAY WITH
SPEEDS LIKELY TO REMAIN BELOW 22 KNOTS. HOWEVER...LONG FETCH DOES
GENERATE 4 FOOT WAVES FROM ROUGHLY DAY BREAK TUESDAY TO TUESDAY
EVENING...ESPECIALLY SOUTH OF MILWAUKEE...APPROACHING SMALL CRAFT
ADVISORY CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
SHORT/LONG TERM...MBK
AVIATION/MARINE...MRC
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000
FXUS63 KGRB 082142
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
342 PM CST SUN NOV 8 2009
.SHORT TERM...TONIGHT AND MONDAY.
MODELS WERE SIMILAR IN DEPICTING PRECIPITATION FALLING FARTHER
NORTH THAN ON PREVIOUS RUNS. THIS CAN BE SEEN IN THE QPF
FIELDS...WHICH NO LONGER COVER THE WHOLE CWA WITH QPF. NORTHERN
WISCONSIN IS FORECAST TO BE IN THE RIGHT ENTRANCE REGION OF A
DEPARTING 300MB JET. A MID LEVEL SHORT WAVE IS EXPECTED TO MOVE
INTO THE REGION TONIGHT AND BUFKIT TIME SECTIONS FROM THE 12Z NAM
INDICATED MUCH MORE LOW LEVEL MOISTURE AROUND 00Z AS A SURFACE LOW
AND WARM FRONT LIFT NORTH INTO/THROUGH WISCONSIN. THE TIME
SECTIONS HAD SUFFICIENT LIFT TODAY BUT NO SIGNIFICANT MOISTURE TO
PRODUCE ANY RAIN. LATE THIS AFTERNOON WHEN LOW LEVEL MOISTURE
BECOMES AVAILABLE...THE LIFT IS NOT AS STRONG THEN...AND IS MAINLY
ELEVATED ABOVE THE MOIST LAYER. AS A RESULT OF THESE
FACTORS...HAVE LEFT THE SLIGHT CHANCE FOR SHOWERS IN THE NORTH
DURING THE EVENING AND THEN A CHANCE OF SPRINKLES AFTER MIDNIGHT.
EXPECT DECREASING CLOUDS ON MONDAY WITH DRIER AIR PUSHING INTO THE
AREA BEHIND THE COLD FRONT. HAVE WARMER LOW TEMPERATURES GOING
TONIGHT DUE TO THE EXPECTED INCREASE IN CLOUDS AND A WARM FRONT
PASSING THROUGH THE CWA. A COLDER AIR MASS WILL LEAD TO COLDER
HIGH TEMPERATURES ON MONDAY.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY
MEDIUM RANGE MODELS HINTING AT A SHIFT FROM THE FAST ZONAL
PATTERN CURRENTLY OVER CONUS TO MORE OF A SPLIT FLOW REGIME WITH
UPPER LOW FORMING OVER SOUTHWEST U.S. A LOT OF UNCERTAINTY YET
WITH BOTH GFS AND ECMWF SHOWING LITTLE RUN TO RUN CONTINUITY AT
THE LATER PERIODS. FOR THE MOST PART...STAYED WITH DRY FORECAST
WITH RELATIVELY MILD DAYTIME TEMPERATURES AS DRY AIR MASS AND
HIGH PRESSURE IN CONTROL OF WEATHER THROUGH THE EXTENDED. WILL KEEP SMALL
CHANCE POPS GOING FOR FRI NIGHT INTO SAT PERIOD ATTM...THOUGH WITH
MODEL SOLUTIONS SHIFTING FURTHER WEST WITH SURFACE LOW...LATER
SHIFTS CAN PROBABLY YANK TOO.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST 03Z BEFORE
LOWER CLOUDS AND PATCHY FOG BEGIN TO DEVELOP. THEN MVFR CIGS AND
AREAS OF MVFR VSBYS ARE LIKELY UNTIL SHORTLY AFTER SUNRISE. CONDITIONS
SHOULD BECOME VFR ONCE AGAIN AROUND 13Z OR 14Z.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TE
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000
FXUS63 KARX 082051
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
251 PM CST SUN NOV 8 2009
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
MAIN FORECAST CONCERNS ARE ON CLOUDS...PRECIPITATION CHANCES AND
TEMPERATURES FOR TONIGHT.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED OVERALL BROAD TROUGHING FROM THE EAST PACIFIC INTO THE
NORTHERN ROCKIES...AND STRONG RIDGING FROM THE OHIO VALLEY INTO THE
SOUTHEAST U.S.. WITHIN THE BROAD TROUGH...THE MOST NOTABLE FEATURES
ARE TWO SHORTWAVES...ONE IN SOUTH DAKOTA AND THE OTHER IN SOUTHERN
SASKATCHEWAN. ASSOCIATED WITH THE SOUTH DAKOTA SHORTWAVE IS A 1009MB
SURFACE LOW NEAR SPENCER IOWA...WITH A WARM FRONT THAT EXTENDED EAST
ALONG THE MINNESOTA/IOWA BORDER. SOUTH OF THIS FRONT...TEMPERATURES
HAVE WARMED INTO THE 70S. EVEN NORTH OF THE FRONT ACROSS THE
NORTHERN PORTIONS OF THE FORECAST AREA...READINGS HAVE CLIMBED INTO
THE MID 60S THANKS TO MORE SUNSHINE THAN EXPECTED. RUC SOUNDINGS
STILL DEPICT PLENTY OF LOW LEVEL MOISTURE ALONG THE FRONT BELOW
900MB... WITH RELATIVE HUMIDITIES AT OR ABOVE 90 PERCENT...BUT LOW
STRATUS HAS YET TO MATERIALIZE. THERE ARE THREE POSSIBLE REASONS:
TIME OF DAY NOT FAVORABLE TO FORM LOW CLOUDS...RELATIVE HUMIDITIES
ARE ACTUALLY CORRECT BUT NOT REACHING FULL SATURATION...LACK OF
CLOUD CONDENSATION NUCLEI. WHATEVER THE CASE...MOSTLY SUNNY SKIES
EXIST WITH ONLY SOME PASSING CIRRUS. BEHIND THE SURFACE LOW IN AN
AREA OF FRONTOGENESIS AND DPVA AHEAD OF THE SOUTH DAKOTA
SHORTWAVE...A BAND OF HIGH BASED ALTOSTRATUS EXISTS. SOME LIGHT RAIN
HAS BEEN REPORTED IN WEST CENTRAL MINNESOTA...OTHERWISE THE BAND IS
DRY.
TONIGHT...SHORTWAVE IN SOUTH DAKOTA IS PROGGED TO RAPIDLY MOVE
NORTHEAST...MOVING ALMOST INTO NORTHEAST ONTARIO BY 12Z MONDAY. THE
ASSOCIATED LOW NEAR SPENCER IOWA THEREFORE ALSO MOVES RAPIDLY
NORTHEAST...AND ITS COLD FRONT BLOWS THROUGH ALL OF THE FORECAST
AREA BY 12Z MONDAY. GIVEN TRENDS UPSTREAM ACROSS NEBRASKA AND SOUTH
DAKOTA...AM NOT VERY IMPRESSED ON PRECIPITATION CHANCES...AND EVEN
CLOUDS BELOW AN ALTOSTRATUS LEVEL. HOWEVER...THERE IS A SIGNAL FOR
DEVELOPMENT THIS EVENING OF A VFR STRATUS DECK NORTH OF I-90 BY THE
07.12Z GFS...NAM...NMM AND 07.15Z SREF...IN ADDITION WITH ENOUGH
VERTICAL MOTION AROUND TO PRODUCE PRECIPITATION. THEREFORE...HAVE
MAINTAINED SOME 20 PERCENT CHANCES OF PRECIPITATION IN AN AREA FROM
WABASHA COUNTY EAST AND NORTHWARD...SPECIFICALLY BETWEEN 03Z AND 09Z
TO ALLOW FOR THE STRATUS DECK DEVELOPMENT AND WHEN THE COLD FRONT
MOVES THROUGH. UNTIL THE FRONT MOVES THROUGH...EXPECT TEMPERATURES
TO REMAIN WARM ALONG WITH INCREASING DEWPOINTS. SHOULD SEE TEMPS
FALL OFF QUICKLY BEHIND THE FRONT...THOUGH...AND HAVE KEPT LOWS
FAIRLY SIMILAR TO THE PREVIOUS FORECAST.
MONDAY AND MONDAY NIGHT...SHORTWAVE CURRENTLY OVER SOUTHERN
SASKATCHEWAN IS FORECAST TO HEAD EAST INTO NORTHERN ONTARIO ON
MONDAY WHILE A SECOND SHORTWAVE OVER BRITISH COLUMBIA MOVES INTO
MANITOBA. WITH THE EASTWARD MOVEMENT OF THESE FEATURES...IT SHOULD
HELP PUSH THE COLD FRONT FROM TONIGHT FARTHER TO THE EAST-SOUTHEAST.
THIS IS CRITICAL BECAUSE PREVIOUS MODEL RUNS SUGGESTED A
FRONTOGENESIS ZONE ALONG AND BEHIND THE COLD FRONT AFFECTING
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THIS FRONTOGENESIS ZONE
IS NOW SOUTH AND EAST OF OUR AREA...ENOUGH SUCH THAT CHANCES OF
PRECIPITATION WERE REMOVED FROM THE FORECAST. IN ADDITION...CLOUD
COVER WAS REDUCED AS WELL...THOUGH IT DOES APPEAR SOME CIRRUS WILL
MOVE ACROSS THE AREA MONDAY NIGHT. THE HIGH CLOUDS ARE RELATED TO
THE SHORTWAVE MOVING INTO MANITOBA ON MONDAY DROPPING SOUTH INTO
WESTERN LAKE SUPERIOR. WITH MORE SUNSHINE ON MONDAY AND 850MB TEMPS
STILL AROUND 6C...EXPECT ANOTHER MILD DAY WITH HIGHS IN THE UPPER
50S AND LOW 60S. LOWERED DEWPOINTS AS WELL WITH BETTER MIXING AND
SEEING MID 20S TO LOW 30S READINGS UPSTREAM IN THE WESTERN DAKOTAS.
WITH ONLY SOME PASSING HIGH CLOUDS MONDAY NIGHT AND DRY AIR...EXPECT
COOLER READINGS. STAYED ON THE LOW END OF GUIDANCE...ESPECIALLY IF
THE CIRRUS DOES NOT MATERIALIZE AS MUCH AS EXPECTED.
TUESDAY AND TUESDAY NIGHT...A QUIET PERIOD IS ANTICIPATED AS HIGH
PRESSURE BUILDS IN AT THE SURFACE AND RIDGING IS PROGGED TO BUILD IN
ALOFT. IN FACT...MUCH OF THIS PERIOD SHOULD BE CLEAR WITH A DRY
CANADIAN AIRMASS BUILDING IN. DESPITE PLENTY OF SUN...850MB TEMPS
ARE A FEW DEGREES C COOLER...AND AS A RESULT HIGHS WILL BE A LITTLE
COOLER THAN MONDAY. GIVEN THE COOLER DAY...THE CLEAR SKIES AND DRY
AIR...TUESDAY NIGHT WILL BE CHILLY COMPARED TO THE PAST FEW NIGHTS.
STAYED AT OR BELOW GUIDANCE.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE SHOWS FAIRLY GOOD
AGREEMENT THROUGH FRIDAY MORNING...THEN DECREASES HEADING INTO THE
WEEKEND. THERE ARE A FEW PARTS OF THE PATTERN THAT ARE CERTAIN...
WHICH INCLUDE TROUGHING OVER THE WESTERN U.S. THURSDAY THROUGH
SATURDAY AND RIDGING THROUGH THE ENTIRE PERIOD FROM THE OHIO VALLEY
INTO THE SOUTHEAST U.S.. THERE IS ALSO SIGNAL FOR RIDGING ACROSS
WESTERN CANADA ON TOP OF THE WESTERN U.S. TROUGH. THEREFORE A SPLIT
FLOW PATTERN IS LIKELY...WHICH WITH THE FORECASTED LOCATIONS OF BOTH
NORTHERN AND SOUTHERN STREAMS...LOOKS TO FAVOR A DRIER FORECAST.
ANOTHER ITEM FAVORING THE DRIER FORECAST IS A LOW PRESSURE SYSTEM
PROGGED BY MOST MODELS OVER THE SOUTHERN PLAINS THIS WEEKEND...
TRAPPING THE GULF OF MEXICO MOISTURE TO OUR SOUTH.
NOW REGARDING THE DETAILS OF THE FORECAST. FOR WEDNESDAY AND
WEDNESDAY NIGHT...RETURN FLOW WILL BE THE RULE IN THE WAKE OF THE
HIGH PRESSURE AREA THAT CROSSED THE AREA TUESDAY NIGHT. THE 08.00Z
ECMWF REMAINS CONSISTENT SHOWING SOME LIGHT PRECIPITATION NORTH OF
I-90 ON WEDNESDAY...ASSOCIATED WITH ISENTROPIC LIFT AHEAD OF A
SHORTWAVE CROSSING MANITOBA AND NORTHERN ONTARIO. THE GFS SHOWS THIS
AS WELL...BUT KEEPS THE AREA DRY. PREFER TO STAY WITH THE DRY
FORECAST FOR NOW...BUT STILL NEEDS WATCHING. NICE TO SEE THE 08.12Z
ECMWF HAS BACKED OFF ON THE PRECIPITATION. THURSDAY AND THURSDAY
NIGHT LOOK DRY AS WELL...WITH A COLD FRONTAL BOUNDARY OUT OVER THE
NORTHERN PLAINS AND JUST BROAD WARM ADVECTION OVER THE FORECAST
AREA. IN FACT...850MB TEMPS COULD APPROACH 8-10C BY 00Z FRIDAY...SO
A MILD THURSDAY IS IN STORE. THINGS GET MORE UNCERTAIN FOR FRIDAY
INTO SATURDAY...BUT IT DOES APPEAR THAT THE COLD FRONT IN THE
DAKOTAS WILL MARCH EAST ACROSS THE AREA DURING THIS TIME FRAME...IN
RESPONSE TO A NORTHERN STREAM SHORTWAVE CROSSING SOUTHERN CANADA.
SPECIFIC TIMING VARIES...WHICH COULD HAVE SIGNIFICANT IMPLICATIONS
ON TEMPERATURES. STILL APPEARS MILD ON FRIDAY...AND IF THERE IS MORE
SUN THAN EXPECTED...WOULD NOT BE SURPRISED TO HAVE ANOTHER 70 DEGREE
DAY. WILL NOT GO THAT WARM GIVEN THE UNCERTAINTIES PRESENT. COOLER
CONDITIONS INVADE FOR SATURDAY PER 08.00Z ECMWF AND 08.06Z GFS AS
850MB TEMPS ARE PROGGED TO FALL TO AROUND 0C. WITH THE COLD FRONT...
MAINTAINED 20 PERCENT CHANCES FOR PRECIPITATION...THOUGH IT IS
CONCEIVABLE THAT DRY CONDITIONS COULD PREVAIL SINCE THE FRONT IS
MOISTURE STARVED. LOOKING AHEAD FOR SATURDAY NIGHT AND SUNDAY...HAVE
KEPT THAT PORTION DRY UNTIL CERTAINTY INCREASES. TEMPERATURES
EXPECTED NEAR NORMAL AS WELL FOR THE END OF THE WEEKEND.
&&
.AVIATION...TONIGHT AND MONDAY
AVIATION CONCERNS LIE IN THE POTENTIAL FOR MVFR/IFR CEILING
DEVELOPMENT FOR TONIGHT INTO MONDAY. MODELS HAVE BEEN CONSISTENT
WITH BLOSSOMING LOW LEVEL SATURATION ACROSS KRST/KLSE AFTER 21Z
TODAY...CONTINUING THROUGH 07-10Z MONDAY WHEN A COLD FRONT SWEEPS
EASTWARD ACROSS THE REGION...SCOURING OUT THIS CLOUD DECK. 08.12Z
NUMERICAL GUIDANCE NOT AS PESSIMISTIC AS PREVIOUS RUNS WHICH
DEPICTED A PROLONGED PERIOD OF IFR CONDITIONS. LATEST SATELLITE
IMAGERY SHOWS SOME LOWER CLOUDS OVER TX/SOUTHERN PLAINS...AND THE
08.12Z RUN/NAM12 ARE CAPTURING THIS. HOWEVER...THEY ALSO DEPICT 925
MB SATURATION OVER IA...WHICH IS MOSTLY CLOUD FREE AT THE MOMENT.
MOST OF THIS SUPPOSED LOW...NEAR SFC MOISTURE IS ALSO SOUTH OF THE
WARM FRONT...WHICH SHOULD STRETCH ACROSS NORTHERN WI BY 00Z TONIGHT.
WOULD EXPECT A BETTER CHANCE FOR LOW STRATUS NORTH OF THE FRONT
RATHER THAN SOUTH OF IT. BELIEVE THE LATEST RUC13 IS HANDLING THE
CLOUD SCENARIO THE BEST...KEEPING THE TAF SITES CLEAN OF LOW CLOUDS
UNTIL THE COLD FRONT MOVES IN...AFTER 00Z. EVEN THEN...CONDITIONS
ARE MORE FAVORABLE TO STAY VFR RATHER THAN DROP INTO THE MVFR/IFR
CATEGORIES. HAVE TRENDED THE 18Z TAFS THIS WAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT/LONG TERM...AJ
AVIATION...REICK
000
FXUS63 KARX 081707
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1105 AM CST SUN NOV 8 2009
.UPDATE...
SHORT TERM FORECAST CONCERNS FOCUS ON THE CLOUD POTENTIAL FOR LATER
THIS AFTERNOON. MODELS OVER THE PAST FEW DAYS HAVE BEEN ADAMANT OVER
LOW CLOUD DEVELOPMENT BETWEEN 19-22Z...AND THE 08.12Z NAM12 AND
LATEST RUC LOW LEVEL RH FIELDS CONTINUE TO SUPPORT THIS.
HOWEVER...WHERE THESE MODELS DEPICT A SATURATED 925 MB LAYER OVER
CENTRAL IA RIGHT NOW...THE SKIES ARE CLEAR //SATELLITE IMAGERY AND
SFC OBS//. BELIEVE THIS NEAR SFC SATURATION IS BEING WAY OVERDONE.
IN ADDITION...THE SFC WARM FRONT ROUGHLY LIES WEST TO EAST FROM
ALONG THE MN/IA BORDER INTO CENTRAL WI. THIS SHOULD CONTINUE TO
ADVANCE NORTHWARD THIS AFTERNOON AS A LOW OVER NEB MOVES NORTHEAST
TOWARD THE REGION. SO...MOST OF THE FORECAST AREA SHOULD BE IN THE
WARM SECTOR...WITH A BETTER CHANCE FOR CLOUDS ALONG AND NORTH OF THE
WARM FRONT. WILL ADJUST CLOUD TRENDS DOWN FOR THIS AFTERNOON AS A
RESULT...AND WILL ALSO REMOVE THE SPRINKLE POSSIBILITIES FOR LATE
AFTERNOON. IF LOW CLOUDS WOULD DEVELOP...THERE WOULD BE ENOUGH
BROADSCALE THERMODYNAMIC LIFT THROUGH IT THAT SOME SPRINKLES/PATCHY
DRIZZLE COULD DEVELOP. AGAIN THOUGH...SEE THIS LOW CLOUD POTENTIAL
TO BE LOW FOR THE REST OF THE DAYLIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
RIECK
000
FXUS63 KARX 080942
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
342 AM CST SUN NOV 8 2009
.SHORT TERM...TODAY THROUGH MONDAY NIGHT.
MAIN CONCERN FOR THIS FORECAST PACKAGE INCLUDES CLOUD COVER AS
WELL AS RAIN/DRIZZLE CHANCES TODAY. THEN ALSO RAIN CHANCES TONIGHT
AND MONDAY WITH PASSAGE OF COLD FRONT.
08.08Z IR IMAGERY SHOWING BROKEN DECK OF MID CLOUDS STREAMING INTO THE
UPPER MISSISSIPPI RIVER VALLEY REGION AHEAD OF SHORTWAVE TROUGH
OVER THE FOUR CORNERS/SURFACE LOW PRESSURE OVER EASTERN COLORADO.
A STATIONARY FRONT EXTENDED FROM THIS LOW EASTWARD INTO NORTHEAST
ILLINOIS. ALSO...RADAR WAS INDICATING WEST TO EAST ORIENTED
ECHOES FROM CENTRAL SOUTH DAKOTA INTO CENTRAL WISCONSIN. THIS WAS
ASSOCIATED WITH 700-500MB LAYER FRONTOGENESIS SIGNAL. THERE WERE A
FEW LOCATIONS REPORTING LIGHT RAIN...HOWEVER AS LAPS SOUNDINGS
SHOWING EXTENSIVE DRY LAYER BELOW 600 MB AND THAT THE PRECIPITATION
FALLING FROM CLOUDS AT 7-15K FT MOST PLACES WERE NOT SEEING RAIN
REACHING THE GROUND.
ALTHOUGH THIS RAIN BAND DID EXTEND INTO THE NORTHERN REACHES OF
THE FORECAST AREA EARLY THIS MORNING...THE FRONTOGENESIS SIGNAL PUSHES
NORTHWARD AS THE MORNING PROGRESSES...AND WITH THE DRY LAYER WHICH
THE RAIN HAS TO GO THROUGH...THINKING IS THAT THE BAND WILL PUSH
NORTH BEFORE ANY RAIN WOULD BE ABLE TO REACH THE GROUND IN THOSE
AREAS SO FORECAST REMAINS DRY.
THE SURFACE LOW OVER COLORADO WILL MOVE NORTHEAST TODAY TOWARDS
NORTHERN IOWA/SOUTHERN MINNESOTA. AS THIS OCCURS...THE FRONTAL
BOUNDARY TO THE SOUTH OF THE REGION WILL PUSH NORTHWARD. THE QUESTION
IS IF A DECK OF STRATUS CLOUDS WILL DEVELOP NORTH OF THE FRONT AS
IT MOVES INTO THE AREA...AND IF IT DOES FORM...IF THERE WILL BE
ANY PRECIPITATION INVOLVED. GFS/NAM BOTH SHOWING 925-850MB
MOISTURE BLOSSOMING THIS MORNING ACROSS NORTHERN IOWA AND SOUTHERN
MINNESOTA THEN MOVING NORTHWARD THROUGH THE DAY AHEAD OF THE
FRONT. MOS GUIDANCE THOUGH NOT INDICATING THIS WILL DEVELOP AND
07.21Z AND 08.03Z SREF NOT BRINGING ANY LOWER CLOUDS INTO THE AREA
UNTIL AFTER 09.00Z. CROSS-SECTIONS/BUFKIT SOUNDINGS FROM THE
NAM/GFS SHOWING THAT THERE WILL BE A SATURATED LAYER...HOWEVER IT
WILL BE VERY SHALLOW. ON THE POSITIVE SIDE FOR DRIZZLE...THERE
WILL BE SOME CONVERGENCE/UPWARD MOTION IN THIS LAYER DUE TO THE
FRONT. HOWEVER CONFIDENCE IS NOT REAL HIGH WITH CLOUD
FORMATION...AND IF STRATUS DOESN/T FORM...PRECIPITATION WILL NOT
BE SEEN THIS AFTERNOON/EVENING. DROPPED RAIN CHANCES TO SPRINKLES
FOR THE LATE AFTERNOON. DID KEEP DRIZZLE IN FOR THE EVENING AS
SOUNDINGS SHOWING A BETTER LOW LEVEL SATURATED LAYER/OMEGA SIGNAL
ACROSS THE NORTH FOR A FEW HOURS. WHAT HAPPENS WITH THE CLOUDS/PRECIPITATION
TODAY WILL GREATLY AFFECT TEMPERATURES. WITH LOWER CONFIDENCE ON
THE STRATUS/RAIN...DID INCREASE HIGHS THIS AFTERNOON...ESPECIALLY
ACROSS THE SOUTH WHERE IT IS LIKELY THAT PERIODS OF SUNSHINE WILL
OBSERVED.
THEN TONIGHT AND MONDAY THE LOW WILL PUSH EAST...MOVING THE FRONT
THROUGH AS A COLD FRONT. MOISTURE WILL BE LIMITED ALONG THE
FRONT...ESPECIALLY IN THE LOWER LEVELS OF THE ATMOSPHERE. 08.00Z
MODELS WERE IN GOOD CONSENSUS OF TRENDING TO A DRIER SOLUTION. DID
THE SAME WITH THIS FORECAST PACKAGE...BY LOWERING CHANCES TONIGHT
AND THEN KEEPING ANY RAIN CHANCES CONFINED TO THE VERY SOUTHERN
AREAS FOR MONDAY AND MONDAY NIGHT. FOLLOWING SHIFTS WILL NEED TO
WATCH THIS AND IF THIS TREND CONTINUES THOUGH...MAY BE ABLE TO DRY
OUT THE FORECAST FOR A PORTION OF THIS PERIOD.
.LONG TERM...TUESDAY THROUGH SATURDAY
HIGH PRESSURE BUILDS IN FOR TUESDAY THROUGH THURSDAY. TAKING FULL
ADVANTAGE OF THE SUNSHINE THAT IS EXPECTED...HIGH TEMPERATURES
THROUGH THIS TIME FRAME WILL BE NEAR TO JUST ABOVE NORMAL. CURRENT
MODELS KEEP THE HIGH OFF-CENTERED FROM THE FORECAST AREA DURING
THE NIGHT-TIME HOURS SO THOUGHTS ARE THAT THE AREA WILL HAVE
ENOUGH BOUNDARY LAYER WIND TO KEEP TEMPERATURES FROM DROPPING OFF
TOO FAR ANY OF THESE NIGHTS. SO NEAR NORMAL LOW TEMPERATURES ARE
ALSO EXPECTED. AS ONGOING FORECAST HAD A GOOD HANDLE ON
THIS...LITTLE ADJUSTMENTS WERE MADE AT THIS TIME.
THE NEXT PRECIPITATION CHANCES WILL MOVE IN THURSDAY NIGHT AND
FRIDAY WITH A COLD FRONT PUSHING ACROSS THE NORTHERN CONUS. THERE
ARE DIFFERENCES IN TIMING BETWEEN 08.00Z MODELS ON THIS FEATURE
WITH GFS BEING A BIT FASTER THAN THE ECMWF. DUE TO THESE
DIFFERENCES...DIDN/T HAVE THE CONFIDENCE TO MAKE ANY MAJOR CHANGES
TO THIS PORTION OF THE FORECAST.
&&
.AVIATION...
PRIMARY CONCERNS WERE WITH WHETHER PREVAILING CONDITIONS WILL DROP
INTO MVFR/IFR FLIGHT CATEGORIES LATER TODAY AND TONIGHT. CONFIDENCE
WAS HIGH THAT VFR CONDITIONS CONTINUE TODAY...AS FRONT TO OUR SOUTH
LIFTS NORTHWARD WITH SURFACE LOW ADVANCING OUT OF THE CENTRAL
PLAINS. LOW LEVEL RELATIVE HUMIDITY INCREASES AHEAD OF APPROACHING
COLD FRONT TONIGHT...WHICH SHOULD LOWER CEILINGS TO MVFR. CONFIDENCE
WAS NOT AS GOOD AS IT COULD BE IN THIS SOLUTION...AS GUIDANCE OF
LATE HAS NOT HANDLED LOW LEVEL CLOUD FORECASTS TOO WELL. FRONTAL
PASSAGE EXPECTED 09.06Z-09.12Z...WHICH SHOULD SCOUR OUT ANY LOW
LEVEL CLOUDS WITH ONSET OF SUBSIDENCE AND DRYING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT/LONG TERM...BROOKS
AVIATION...THOMPSON
000
FXUS63 KMKX 080928
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
328 AM CST SUN NOV 8 2009
.DISCUSSION...FORECAST FOCUS IS ON CLOUD/TEMP TRENDS TODAY AND THEN
ON ASSESSING RELATIVELY SMALL PRECIP CHANCES WITH PASSAGE OF
SHORTWAVE/COLD FRONT COMBO MONDAY/MONDAY NIGHT.
TODAY-
WATCHING FOR STRATUS BUT SO FAR NOTHING. PLENTY OF CIRRUS AND EVEN
SOME MID CLOUDS UPSTREAM. THE MID DECK FROM SOUTH DAKOTA INTO NW
WI...WITH MAINLY CIRRUS ELSEWHERE. 850 WARM AIR ADVECTION BOOSTS 850
TEMPS INTO THE 13-16C RANGE AND THE 925 TEMPS ARE STILL VERY
WARM...12-14C. EXPECTING SURFACE WARM FRONT TO MOVE ACROSS THE CWA
WITH A SE WIND KEEPING THE EAST COOLER THAN YESTERDAY. EVERYWHERE
ELSE DEPENDS ON THE CLOUD COVER. FOR NOW THINK TEMPS WILL APPROACH
OR EXCEED MOS ESPECIALLY AT INLAND LOCALES IN THE ABSENCE OF
STRATUS.
TONIGHT-
SURFACE/850 LOWS TRACK TO OUR NORTHEAST AND DRAG BOUNDARY INTO THE
NW CWA TOWARDS MORNING. SOUNDINGS/MOS/PROGGD FORCING ALL SUGGEST
KEEPING THINGS DRY. 00Z ECMWF DOES BRING A BIT OF QPF INTO THE FAR
NW CWA LATE...BUT WILL SIDE WITH THE SINGLE DIGIT MOS POPS FROM THE
GFS AND MOS AND GO WITH THE DRY LOOK.
MONDAY-
SURFACE LOW LIFTS NORTHEAST DRAGS THE SURFACE AND 850 FRONT THROUGH
THE CWA. THE NAM IS MOST AGGRESSIVE BLOSSOMING THE QPF. THE CANADIAN
AND NAM ARE COMPLETELY DRY. THE GFS/ECMWF SUGGEST THE SE CWA HAS
SOME POTENTIAL FOR LIGHT QPF. WILL KEEP THE CHANCE IDEA IN PLACE IN
THE SE...WITH SLIGHT CHANCE NW CWA.
TUESDAY-
MID LEVEL SHORT WAVE SHIFTS INTO EASTERN GREAT LAKES WITH
ANTICYCLONIC VORTICITY ADVECTION IN THE WAKE. SURFACE AND 850
MILLIBAR HIGH PRESSURE RIDGE GRADUALLY SHIFTS OVER SOUTHERN WI LATER
IN THE DAY. 850 COOL POOL LINGERS.
WEDNESDAY-
SURFACE AND 850 RIDGE AXES SHIFT TO OUR EAST. WARM AIR ADVECTION
RETURNS WITH THIS INTERCEPTING A 700/500 RIDGE RIDER BUT WELL NORTH
OF THE CWA SO THE DRY LOOK STILL APPEARS ON TRACK AT THIS POINT.
THURSDAY-
WARM ADVECTION AND SOUTHERLY FLOW REALLY REVS UP AS LOW DEVELOPS IN
THE PLAINS. UPPER JET AND POSITION OF SHORT WAVE ENERGY KEEPS PRECIP
WELL TO OUR NW.
&&
.AVIATION...WEAK STATIONARY FRONT STALLED OVER NORTHERN ILLINOIS SHOULD LIFT
NORTH TODAY AS WARM FRONT AS LOW PRESSURE MOVES INTO SOUTHERN
MINNESOTA THIS EVENING. MAINLY CLEAR SKIES AND LIGHT WINDS HAVE
LEAD TO PATCHY MVFR TO IFR FOG THIS MORNING...MAINLY AT KENW. THIS
SHOULD BURN OFF RATHER QUICK.
LOW RISK OF ADVECTION FOG COMING OFF LAKE MICHIGAN IN SOUTHEAST FLOW
REGIME TODAY AT KMKE...BUT TOO LOW TO INCLUDE IN TAF.
GFS...AS USUAL...MORE AGGRESSIVE WITH LOW LEVEL MOISTURE TONIGHT
INTO MONDAY AND WOULD SUGGEST MVFR STRATUS DECK FORMATION ESPECIALLY
AFTER MIDNIGHT TONIGHT.
GIVEN TRACK RECORD OF GFS OVERFORECASTING STRATUS...WILL BE
CONSERVATIVE AND LEAVE OUT OF TAFS. HOWEVER...DECENT CHANCE OF MVFR
VISIBILITY WITH INCREASING MOISTURE AND MAINLY CLEAR EVENING. HIGH
CLOUDS DO NOT APPEAR TO SPREAD IN THICK UNTIL AFTER MIDNIGHT SO WILL
INCLUDE LIGHT FOG IN MOST TAFS FOR TONIGHT.
&&
.MARINE...SHOULD BE RATHER QUIET WITH LIGHT WINDS TODAY AND
TONIGHT.
WILL HAVE TO WATCH LIGHT SOUTHEAST FLOW REGIME LATER TODAY AND
TONIGHT FOR POSSIBLE ADVECTION FOG BUT RISK LEVEL MARGINAL TO
INCLUDE FOR NOW.
NORTH-NORTHEAST WINDS PICK UP LATE MONDAY NIGHT INTO TUESDAY WITH
SPEEDS LIKELY TO REMAIN BELOW 22 KNOTS. HOWEVER...LONG FETCH DOES
GENERATE 4 FOOT WAVES FROM ROUGHLY DAY BREAK TUESDAY TO TUESDAY
EVENING SO MAY NEED A SMALL CRAFT ADVISORY FOR WAVES ON LATER SHIFTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
SHORT/LONG TERM...COLLAR
AVIATION/MARINE...CRAVEN
000
FXUS63 KGRB 080842
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
242 AM CST SUN NOV 8 2009
.SYNOPSIS...RELATIVELY LOW AMPLITUDE FLOW EXPECTED FOR THE FCST
PERIOD...WITH MEAN TROF POSN TO THE W AND RIDGE TO THE E. SOME
TENDENCY TO SPLIT STILL EXPECTED LATER IN THE PERIOD. THE PATTERN WL
KEEP MILD PACIFIC AIR STREAMING ACRS THE RGN...AND RESULT IN ABV
NORMAL TEMPS. TWO MAIN SYSTEMS WL BRING CHCS OF PCPN TO THE AREA.
THE FIRST WL MV ACRS THE RGN EARLY...BUT WITH VERY LIMITED MOISTURE
PCPN LIKELY TO BE SCT AND AMNTS VERY LGT. SECOND WL ARRIVE LATER IN
THE WEEK AND NEXT WEEKEND.
&&
.SHORT TERM...TDA/TNGT/MON. TREND ON THE MODELS CONCERNING THE
INCOMING SYSTEM HAS BEEN TO PULL BACK ON PRECIP...AND TO SOME EXTENT
EVEN CLOUDS. HARD TO ARGUE WITH THAT SINCE THAT/S HOW THE LAST
SYSTEM PLAYED OUT...AND 00Z RAOBS OUT TO THE W AND SW WERE VERY DRY.
SO...PUSHED FCST IN THAT DIRECTION. KEPT JUST CHC OF SPRINKLES OVER
N-C WI TDA...AND WENT WITH JUST SPRINKLES OVER ALL BUT E-C WI TNGT.
MODELS ALSO SUGGESTED FRONTAL CLOUD BAND WL BE SHIFTG SEWD AFTER
MIDNIGHT...SO STARTED DECR CLD TREND OVER THE NW PART OF THE FCST
AREA LATE.
SUPPOSE THERE COULD BE SOME SPRINKLES OVER E-C WI EARLY MON...BUT AT
THIS POINT CHC SO MARGINAL WL JUST LEAVE THEM OUT. WENT WITH MORE
SUN OVER THE NW PART OF THE AREA...BUT THE SE COULD STILL SEE CI ON
THE NW EDGE OF FRONTAL CLOUD BAND.
GUID TEMPS FOR TDA QUITE WARM AND 850 MB TEMPS REALLY DON/T FALL OFF
MUCH FM YDA AFTN. BUT WE WL BE GETTING OFF TO A COLDER START...NOT
GET FULL SUN LIKE YDA...AND HAVE A DEVELOPING SELY FLOW. SO ALTHOUGH
THE BIAS CORRECTED MAV GUID HAS BEEN DOING WELL...IT SEEMED TOO
WARM. INSTEAD WENT WITH A MORE ROBUST BLEND OF THE VARIOUS GUID
PRODUCTS...AND LOWERED TEMPS A LITTLE MORE LAKESIDE WHERE WATER
TEMPS ARE ARND 50. USED BLENDS OF GUID FOR TNGT AND MON AS WELL.
THAT RESULTED IN GOING A LITTLE COOLER IN WRN AREAS TNGT...AND A
LITTLE WARMER MOST AREAS MON. THAT FIT WITH HAVING CLDS DECR IN THE
W LATER TNGT...AND FEWER CLDS ON MON THAN PREVIOUSLY ANTICIPATED.
.LONG TERM...MON NGT THRU NXT SAT. MEAN FLOW FOR THE FIRST HALF OF
THE WEEK TO BE DICTATED BY AN ERN PACIFIC/WRN CONUS UPR TROF WITH
A SOMEWHAT FLAT DOWNSTREAM UPR RDG OVR THE CNTRL CONUS. THIS PATN
TO KEEP A DRY AND MILD WEATHER REGIME OVR NE WI. A PIECE OF SHRTWV
ENERGY TO EJECT NEWD FROM THE MAIN TROF AND MOV NE TOWARD THE
GREAT LKS LATE NXT WEEK. THIS WOULD APR TO BE THE FIRST
OPPORTUNITY OF SEEING ANY PCPN...BUT TIMING AND EXTENT STILL UP
FOR DEBATE AMONG THE MDLS. MAIN FCST CHALLENGE IN THE SHORT-TERM
WL BE TEMPS AND PCPN QSTNS THE LONG RANGE ISSUE.
INDICATIONS ARE THAT ANY FRONTOGENETICAL FORCED PCPN WL REMAIN SE
OF THE FCST AREA MON NGT...LEAVING AN INFLUX OF DRIER AIR TO
STEADILY OVERSPREAD WI AHD OF AN AREA OF HI PRES SITUATED OVR THE
MIDWEST. LOOK FOR SKIES TO BECOME MOSTLY CLR OVR NRN AND CNTRL WI
WITH E-CNTRL WI SEEING A GRADUAL DECREASE IN CLDS. THIS DECREASE
IN CLDS...COUPLED WITH DIMINISHING WNDS WL ALLOW TEMPS TO DROP OFF
PRETTY WELL. MIN TEMPS WL RANGE FROM AROUND 30 DEGS NORTH TO THE
UPR 30S NEAR LK MI.
THE HI PRES MOVS EAST AND WL BE LOCATED RIGHT OVR THE HEART OF WI
ON TUE...BRINGING PLENTY OF SUNSHINE TO THE RGN. TEMPS WL BE A BIT
COOLER THAN THE PAST COUPLE OF DAYS WITH 8H TEMPS ONLY AROUND +3C.
NEVERTHELESS...LOOK FOR MAX TEMPS TO REACH THE 50 TO 55 DEG RANGE
WHICH WOULD BE 5 TO 10 DEGS ABV NORMAL.
AS THE HI PRES SLOWLY HEADS EAST ACROSS LWR MI TUE NGT...A RETURN
FLOW WL GRADUALLY DVLP OVR WI. LGT SOUTHERLY WNDS WL NOT BE ENUF
TO STOP TEMPS FROM FALLING WITH SKIES STILL MOSTLY CLR. TUE NGT
STILL APRS TO BE THE COOLEST OF THE EXTENDED PERIOD WITH UPR 20S
OVR THE NORTH TO THE MID 30S NEAR THE LAKE. S-SW WNDS FIRMLY IN
PLACE OVR THE RGN ON WED AS THE RELATIVELY FLAT UPR RDG TO BE
SITUATED OVR THE CNTRL CONUS. MDLS DO SHOW A VERY WEAK SHRTWV
TROF/EMBEDDED SHRTWV TO BE MOVG ALONG THE U.S.-CANADIAN BORDER
WHICH MAY INTERACT WITH SOME ISEN LIFT TO GENERATE A BAND OF CLDS
(ESP OVR THE NORTH). ONLY THE ECMWF DVLPS LGT PCPN WITH THESE
FEATURES...HOWEVER DUE TO THE DRY AIRMASS IN PLACE...HAVE KEPT WED
DRY. ONLY CHG TO WED WL BE TO ADD A FEW MORE CLDS TO THE NORTH
WHICH MAY KEEP TEMPS FROM REACHING 50 DEGS.
A MORE PRONOUNCED SHRTWV TROF IS PROGGED TO MOV INTO THE NRN
PLAINS ON THU AND HELP PUSH A CDFNT INTO THE UPR MIDWEST BY 00Z
FRI. EVEN THO THIS SYSTEM WL AID IN THE INCREASE IN BOTH LOW-LVL
MSTR AND ISEN ASCENT...THE AIRMASS IS STILL RELATIVELY DRY AND
FORCING IS RATHER WEAK. PREFER TO ONLY MENTION A SLGT CHC OF LGT
RAIN FOR N-CNTRL WI WHERE STRONGER ISEN LIFT TO BE PRESENT. MORE
CLDS NORTH...LESS CLDS SE WL PROVIDE A WIDER RANGE IN THE TEMPS
WITH UPR 40S NORTH TO MID 50S SE.
CHC OF PCPN BECOME AN ISSUE FOR THE END OF THE WEEK AS THE MDLS
CONT TO STRUGGLE WITH THE STRENGTH OF OF THE SHRTWV TROF MOVG
ACROSS THE UPR MIDWEST/NRN SECTIONS OF THE GREAT LKS. THE GFS
REMAINS THE MOST RAMBUNCTIOUS...THE ECMWF RATHER FEEBLE...WITH THE
CANADIAN SOMEWHERE IN BETWEEN (AND SLOWER). PRELIM INDICATIONS
WOULD SEEM TO POINT TO A CHC OF LGT RAIN ACROSS N-CNTRL WI THE NGT
AND OVR MOST OF THE FCST AREA ON FRI AS THE CDFNT SLOWLY PUSHES
INTO WI. BETTER CHCS FOR PCPN WOULD THEN SAG SOUTH BY SAT AS THE
FNT GRINDS TO A HALT AS IT BECOMES PARALLEL WITH THE MEAN FLOW
ALOFT.
&&
.AVIATION...VFR CONDITIONS EXPECTED TDA. MVFR VSBYS WITH FOG
LIKELY MOST AREAS TNGT. AT THIS POINT MOISTURE LOOKS TOO LIMITED
FOR WIDESPREAD IFR CIGS TNGT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SKOWRONSKI/KALLAS
000
FXUS63 KMKX 072124
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
320 PM CST SAT NOV 7 2009
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
SHORT TERM CONCERNS INCLUDE QUESTION OF LOW CLOUD DEVELOPMENT LATER
TONIGHT AND SUNDAY...AND THREAT OF PRECIP IN LATER PERIODS.
NORTHWEST WINDS WILL CONTINUE TO USHER IN EVEN DRIER LOW LEVEL AIR
INTO THE EVENING BEFORE WINDS DECOUPLE AND BEGIN VEERING TO THE
EAST. A PLEASANT EVENING AS WINDS DIMINISH AND TEMPS DROP FROM
/NEAR/ RECORD LEVELS INTO THE 50S. MODIS SEA SURFACE IMAGERY SHOW
NEARSHORE LAKE TEMPS AROUND 50 SO ONSHORE WINDS LATER TONIGHT WILL
SLOW PLUMMETING TEMPS NEAR THE LAKE. OTHR WENT WITH A BLEND OF
MAV/MET GUIDANCE FOR OVERNIGHT LOWS.
PREFER SLOWER GFS NORTHWARD MOVEMENT OF WMFNT ON SUNDAY SO ONSHORE
COMPONENT WILL KEEP LAKESHORE AREAS NOTICEABLY COOLER...ESPECIALLY
NORTH OF KMKE. KEPT KSBM IN THE UPPER 50S...WHILE A LARGER TEMP
GRADIENT CAN BE EXPECTED ACROSS LAKESHORE COUNTIES FARTHER SOUTH.
HI TEMPS SUN TRICKY...ESPECIALLY IN EAST AND NORTH. BEST LOW LEVEL
CONVERGENCE HOLDS OFF UNTIL LATER SUN MRNG AND AFT AS THE FRONT
SHIFTS NWD FROM NRN IA/SRN MN INTO PTNS OF SRN WI. HENCE WL GO WITH
THICKENING CLOUDS FOR SUNDAY WITH BKN TO OVC MID TO LOW CLOUDS
BECOMING MORE EXPANSIVE OVR NRN CWA DURING THE DAY. WEAK FORCING AS
SHORT WAVE RIPPLE PASSES ACROSS NRN WI SUN NGT...BUT DRY AIR
REINFORCED IN THE MID LEVELS WITH SRY WINDS.
BEST CHANCE FOR MORE WIDESPREAD LIGHT RAIN TIED TO PERIOD OF
ENHANCED SYNOPTIC SCALE FORCING AS RIGHT ENTRANCE REGION PASSES
ACROSS SRN WI LATER MONDAY. Q-VECTOR CONVERGENCE INCREASES TO 10 TO
15 UNITS IN THE MID LEVELS. BUMPED UP CHANCE POPS SLIGHTLY...BUT
STILL SOME CONCERN DUE TO LACK OF SIGNIFICANT SATURATION IN THE MID
LEVELS DURING THIS PERIOD. IF TREND CONTINUES...LATER SHIFTS MAY
WANT TO BUMP UP POPS FURTHER. LIGHT RAIN THREAT CONTINUES THRU MON
NIGHT BEFORE DRIER AIR AND SUBSIDENCE RETURN FOR MID WEEK.
.LONG TERM/TUESDAY NIGHT THROUGH SATURDAY/...
LONG TERM GUIDANCE IN GOOD AGREEMENT FOR FIRST PERIODS OF EXTENDED
WITH LARGE SCALE RIDGING AND QUIET CONDITIONS. LEANING TOWARD MORE
CONSISTENT HI RES ECMWF IN LATER PERIODS..WHICH IS IN BETTER
AGREEMENT WITH CANADIAN AND UKMT GUIDANCE. REMNANTS OF IDA GET
CAUGHT IN INCREASING SOUTHERLY FLOW AHEAD OF SHORT WAVE TROUGH AND
PUSHES OUT TO SEA ON WED. WITH HIGHER AMPLITUDE TROFFING OFF EAST
COAST...MORE UPSTREAM RIDGING OVER CENTRAL CONUS WL SERVE TO
POSTPONE ARRIVAL OF NEXT WAVE LATE IN THE WORK WEEK. HENCE REMOVED
LOW POPS ON THU AND THU NIGHT. INTRODUCED LOW POPS FOR THE WEEKEND
AS CUTOFF LOW OVER INTERMOUNTAIN REGION GETS PUSHED EWD BY NEXT
UPSTREAM WAVE PUSHING ACROSS ERN PAC. WITH MINIMAL PRECIP AND
LIMITED CLOUD COVER EXPECTED...DAYTIME TEMPS TO REMAIN AOA NORMAL
UNTIL EARLY NEXT WEEK AFTER WEEKEND SYSTEM.
LARGE POSITIVE 500H ANOMOLY CURRENTLY OVER GTLAKES AND CENTRAL CONUS
DOES WEAKEN OVER THE NEXT WEEK...BUT 5 DAY ANOMOLIES POINTING AT
VERY LARGE NEGATIVE ANOMOLY FORMING OVER THE GULF OF AK....WHICH IS
IN AGREEMENT WITH BOTH ECMWF AND GFS FOR NEXT WEEKEND. INTERESTING
TO SEE IF THIS POPS MORE UPSTREAM RIDGING AND WARMER 500H HEIGHTS
OVER CENTRAL CONUS FOR WEEK OF NOV 15TH...OR IF FLOW REMAINS MORE
ZONAL AND CONDITIONS TURN COLDER AND UNSETTLED.
&&
.AVIATION...THE LOW PRESSURE TROUGH WILL STAY STALLED OUT OVER
SOUTHERN WI TONIGHT...AND THEN RETURN SOUTHERLY FLOW WILL BEGIN
AGAIN AHEAD OF THE NEXT SYSTEM FOR SUNDAY AND MONDAY. MVFR STRATUS
FORMATION IS AGAIN POSSIBLE SUNDAY LATE MORNING...BUT CONFIDENCE IS
NOT HIGH. ACCOUNTED FOR POSSIBILITY BY PUTTING SCT IN TAFS. BEST LOW
LEVEL CONVERGENCE FOR STRATUS DEVELOPMENT WILL BE FOCUSED JUST TO
THE NORTH OF THE TAF SITES.
PASSAGE OF LOW PRESSURE TROUGH ACROSS SOUTHERN WI COULD BRING RAIN
AND PATCHY FOG SUN NIGHT AND MON. IFR CIGS/VSBYS POSSIBLE...ALTHOUGH
TO A LESSER DEGREE AT MKE.
&&
.MARINE...
LIGHT WINDS OVERNIGHT WITH A LOW PRESSURE TROUGH STALLED OVER
SOUTHERN WISCONSIN. WINDS WILL INCREASE OUT OF THE SOUTH TO
SOUTHEAST SUN AFTERNOON...BUT WINDS AND WAVES EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
SHORT/LONG TERM...MBK
AVIATION/MARINE...MRC
000
FXUS63 KGRB 072121
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
321 PM CST SAT NOV 7 2009
.SHORT TERM...TONIGHT AND SUNDAY.
MODELS ARE SIMILAR FOR TONIGHT...SHOWING A FRONTAL BOUNDARY PASSING
SOUTHEAST OF WISCONSIN DURING THE EVENING AS SURFACE HIGH PRESSURE
SETTLES OVER THE STATE. MIDDLE AND HIGH CLOUDS ARE EXPECTED TO
SPREAD ACROSS NORTHERN WISCONSIN LATER TONIGHT BUT...AT 21Z...SUNSET
WAS QUICKLY APPROACHING...DEW POINTS WERE VERY LOW...AND WINDS
WILL BE LIGHT WITH THE HIGH. THESE FACTORS SHOULD ALLOW
TEMPERATURES TO FALL QUICKLY ONCE THE SUN SETS. HAVE MENTIONED
SOME FOG NEAR THE UPPER MICHIGAN BORDER SINCE DEW POINTS ARE
EXPECTED TO INCREASE AS THE INVERSION STRENGTHENS WITH THE LACK OF
MIXING.
THE SURFACE BOUNDARY WILL START TO LIFT NORTH ON SUNDAY BUT CLOUDS
ARE EXPECTED TO PUT A DAMPER ON TEMPERATURES. THUS HAVE GONE WITH
COOLER TEMPERATURES THAN TODAY. MODELS DIFFER IN THEIR TREATMENT
OF PRECIPITATION. HAVE LOWERED POPS A BIT BUT KEPT A SMALL CHANCE
OF RAIN IN NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON SURROUNDED
BY A CHANCE OF SPRINKLES TO THE EAST AND SOUTH...ASSOCIATED WITH
LIFT FROM WARM ADVECTION.
.LONG TERM...SUNDAY NIGHT THRU NEXT SATURDAY. BROAD...NEARLY ZONAL
FLOW CONTINUES FROM WESTERN CONUS TO EASTERN CANADA...CONTINUING
MILD/AT OR ABOVE NORMAL TEMPERATURES INTO NEXT WEEKEND.
FOR EARLY PERIODS...LOW PRESSURE TO LIFT NORTHEAST OUT OF PLAINS
INTO WISCONSIN SUNDAY NIGHT...DRAGGING A COLD FRONT THROUGH MON
MORNING. SYSTEM HAS DYNAMICAL SUPPORT FROM RRQ OF 100 KT
JET EXITING THROUGH LAKE SUPERIOR...THOUGH DRY AIR MASS IN PLACE WILL
LIMIT PCPN CHANCES. MODEL CROSS SECTIONS SHOWING MOISTURE RATHER
SHALLOW. WITH SHORT WAVE JUST COMING ON SHORE TODAY...STILL LOT OF
UNCERTAINTY. WILL STAY WITH LOW POPS...BUT TEND TO BE A BIT MORE
PROGRESSIVE GIVEN MEAN FLOW. HIGH PRESSURE BUILDS IN FOR DRY
PERIOD MONDAY NIGHT THROUGH WEDNESDAY.
FOR WED THROUGH SAT...UNCERTAINTY HIGH ON POPS AS MODELS STRUGGLE
WITH TIMING OF WAVES EXPECTED TO TOP RIDGE POSITION OVER WESTERN
LAKES. WILL LEAN TOWARDS DRY FORECAST INTO FRI MORN...AS DYNAMICS
FOCUSED NORTH AND DRY AIR MASS IN PLACE. FRONTAL BOUNDARY NEARS
REGION LATER PERIODS...INCREASING RAIN CHANCES.
&&
.AVIATION...SOME MVFR VSBYS ARE POSSIBLE AFTER 06Z TONIGHT NEAR
THE WI/UPPER MI BORDER. OTHERWISE VSBYS SHOULD BE VFR AND CIGS WILL BE
VFR...WITH JUST MIDDLE AND HIGH CLOUDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MG/TE
000
FXUS63 KARX 072030
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
229 PM CST SAT NOV 7 2009
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
MAIN FORECAST CONCERNS ARE LOW PRECIPITATION CHANCES FOR SUNDAY
THROUGH MONDAY NIGHT.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED NEARLY ZONAL FLOW ACROSS THE WESTERN TWO THIRDS OF NORTH
AMERICA...THOUGH IT DOES APPEAR BROAD TROUGHING IS TRYING TO FORM IN
THE PACIFIC NORTHWEST. ALSO OF NOTE ARE A FEW SHORTWAVES IN NEVADA
AND ARIZONA RIDGING THROUGH THE FLOW. CLOSER TO HOME...MOSTLY SUNNY
SKIES PREVAIL WITH A DRY AIRMASS IN PLACE ACROSS MUCH OF THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. 12Z MPX AND ABR
SOUNDINGS BOTH SHOWED DEWPOINT DEPRESSIONS OF 15C OR GREATER BETWEEN
750-950MB. THESE SUNNY SKIES ARE ACCOMPANIED BY HIGH PRESSURE
BUILDING IN AT THE SURFACE BEHIND A PACIFIC COLD FRONT THAT CROSSED
EARLY THIS MORNING. THE CENTER OF THE HIGH IS OVER SOUTHWEST
MINNESOTA. DESPITE THE FRONTAL PASSAGE...SURFACE TEMPERATURES HAVE
RISEN WELL INTO THE 60S (EVEN 70 AT DECORAH AND PRAIRIE DU CHIEN)...
AIDED BY THE FACT THAT 850MB TEMPS DROPPED OFF SLOWLY BEHIND THE
FRONT. AT 12Z...THEY WERE STILL 15C AT MPX...COMPARED TO 6C AT ABR.
TONIGHT...UPPER LEVEL FLOW IS PROGGED TO TURN SOUTHWESTERLY AS THE
TROUGHING BECOMES A LITTLE DEEPER OVER THE NORTHERN ROCKIES. IN
ADDITION...ONE OF THE SHORTWAVES IN NEVADA IS PROGGED TO MOVE
ACROSS. HOWEVER...WITH A DRY AIRMASS IN PLACE AND ANTICYCLONIC FLOW
AT THE SURFACE...NO PRECIPITATION IS EXPECTED. THE SOUTHWEST FLOW
WILL BRING SOME HIGHER CLOUDS INTO THE AREA...THOUGH...WHICH CAN
ALREADY BE SEEN OVER WESTERN NEBRASKA. LOW TEMPERATURES TONIGHT WILL
DEFINITELY BE COOLER THAN LAST NIGHT DUE TO LESS WIND AND A DRIER
AIRMASS IN PLACE. NO REASONS EXIST TO STRAY MUCH FROM GUIDANCE.
SUNDAY INTO SUNDAY NIGHT...FOCUS OF ATTENTION TURNS TO THE COLD
FRONT THAT PASSED THROUGH THE AREA EARLIER THIS MORNING. TONIGHT...
THIS FRONT IS FORECAST TO RETURN NORTHWARD AS A WARM FRONT DUE TO
THE UPPER FLOW TURNING SOUTHWESTERLY...REACHING SOUTHERN IOWA AT 12Z
SUNDAY. AS THE TROUGHING IN THE NORTHERN ROCKIES LIFTS
EAST-NORTHEAST PER MODEL PROGS...AND THE SHORTWAVE IN ARIZONA MOVES
NORTHEAST THROUGH THE FLOW...THE WARM FRONT WILL CONTINUE LIFTING
NORTH. IN ADDITION...MODELS SHOW A SURFACE LOW TO ACCOMPANY THE
SHORTWAVE...WHICH WOULD MOVE ACROSS WINONA MN SUNDAY EVENING. THE
COLD FRONT ASSOCIATED WITH THE SURFACE LOW SHOULD CROSS MUCH OF THE
CWA BY 12Z MONDAY...WITH HIGH PRESSURE BUILDING IN BEHIND IT ACROSS
THE DAKOTAS. THE SYSTEM IMPACTS TO THE AREA IN THE PRECIPITATION
DEPARTMENT APPEAR TO BE MINIMAL...WITH PERHAPS A LITTLE LIGHT RAIN
OR DRIZZLE. THIS IS DUE TO SHALLOW MOISTURE AND WEAK FRONTOGENETICAL
FORCING. IF ANY PRECIPITATION FALLS...IT SHOULD BE CONFINED TO THE
SUNDAY AFTERNOON TO SUNDAY NIGHT TIME AND ONLY ACCUMULATE TO A FEW
HUNDREDTHS AT MOST. ALTHOUGH VERY LITTLE PRECIPITATION IS
EXPECTED...LOOK FOR A WIDESPREAD STRATUS DECK TO DEVELOP NORTH OF
THE WARM FRONT ON SUNDAY...DUE TO THE HIGHER DEWPOINTS ACROSS
OKLAHOMA AND MISSOURI MOVING INTO THE COOLER AIRMASS OVER THE AREA.
STRATUS WILL ALSO ACCOMPANY THE COLD FRONT...MORESO RELATED TO
FRONTOGENESIS ON TOP OF IT. SOME CLEARING MAY TRY TO ENCROACH INTO
THE FAR WESTERN PORTIONS OF THE FORECAST AREA TOWARDS 12Z MONDAY...
AS DRIER AIR ADVECTS IN ASSOCIATED WITH THE HIGH PRESSURE AREA. HIGH
TEMPERATURES ON SUNDAY ARE TRICKY... ESPECIALLY IN NORTHEAST IOWA
AND FAR SOUTHWEST WISCONSIN WHERE SOME PARTIAL CLEARING COULD OCCUR
IN THE AFTERNOON...AND THAT AREA IS FORECAST TO ENTER THE WARM
SECTOR. WENT WITH A BLEND OF GUIDANCE FOR NOW. MOST AREAS SHOULD END
UP WARMER SUNDAY NIGHT WITH CLOUDS AROUND...WITH LOWS IN THE MID 40S
TO LOW 50S.
MONDAY INTO MONDAY NIGHT...UPPER TROUGH COMING OUT THE NORTHERN
ROCKIES SUNDAY AND SUNDAY NIGHT IS CREATING SOME ISSUES AMONGST THE
MODELS...AND HAS IMPLICATIONS ON PRECIPITATION FOR PORTIONS OF THE
FORECAST AREA DURING THIS TIME FRAME. THE 07.12Z NAM/UKMET ARE BOTH
FAIRLY PROGRESSIVE...HAVING IT OVER NORTHERN ONTARIO BY 00Z TUESDAY.
THE 07.12Z ECMWF...AT THE SAME TIME...STILL HAS IT BACK OVER
NORTHERN MINNESOTA WHILE THE 07.12Z GFS IS EVEN FARTHER WEST OVER
EASTERN NORTH DAKOTA. HPC PREFERENCE PER THE PMDHMD IS A BLEND OF
THE GFS/ECMWF...WHICH WAS FOLLOWED FOR THIS FORECAST. FRONTOGENESIS
ZONE ALONG AND BEHIND THE COLD FRONT CROSSING THE AREA SUNDAY NIGHT
SHOULD BE SLOW TO MOVE TO THE SOUTHEAST DURING THE PERIOD...GIVEN
THE SLOWER UPPER TROUGH. AS A RESULT...HAVE HELD ONTO SOME 20-30
PERCENT CHANCES OF PRECIPITATION FOR BOTH MONDAY AND MONDAY NIGHT IN
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. OUTSIDE OF THIS AREA...
DRY ADVECTION FROM HIGH PRESSURE VERY SLOWLY BUILDING IN SHOULD
GRADUALLY HELP SCOUR OUT THE CLOUDS NORTHWEST TO SOUTHEAST. BY 12Z
TUESDAY...ENVISION MOSTLY CLEAR SKIES WILL ENCOMPASS MUCH OF THE
FORECAST AREA. HIGHS ON MONDAY LOOK TO STILL END UP MILD DESPITE THE
COLD FRONTAL PASSAGE...SINCE 850MB TEMPS AT 00Z TUESDAY ARE 4-6C.
THE CLEARING MONDAY NIGHT AND DIMINISHING WINDS WILL ALLOW READINGS
TO FALL INTO 30S...PERHAPS EVEN CLOSE TO 30 IN TAYLOR COUNTY AND FAR
WESTERN PORTIONS OF THE FORECAST AREA.
.LONG TERM...TUESDAY THROUGH SATURDAY
MODEL/ENSEMBLE AGREEMENT ON THE UPPER LEVEL PATTERN ACROSS THE
COUNTRY DURING THE LONG TERM PORTION OF THE FORECAST IS REALLY GOOD
THROUGH ABOUT THURSDAY...THEN DROPS OFF FOR FRIDAY INTO THE WEEKEND.
UNTIL THURSDAY NIGHT...THE PATTERN SHOWN CONSISTS OF RIDGING
BUILDING INTO THE AREA ON TUESDAY IN THE WAKE OF MONDAY NIGHTS
TROUGH...AND THEN THIS RIDGE FLATTENING OUT BUT HOLDING STRONG OVER
THE EASTERN TWO-THIRDS OF THE COUNTRY AS TROUGHING FORMS IN THE
WESTERN U.S.. THE IMPACT OF THIS PATTERN FOR THE FORECAST AREA IS
FOR DRY AND COOL CONDITIONS ON TUESDAY AS A SURFACE HIGH BUILDS
IN...THEN CONTINUED DRY CONDITIONS WITH GRADUAL WARMING THROUGH
THURSDAY AS THE HIGH PUSHES OFF TO THE EAST. ONE CAVEAT IS OVER
TAYLOR AND CLARK COUNTIES ON WEDNESDAY WHERE THE 07.00Z AND 07.12Z
ECMWF INDICATE SOME LIGHT PRECIPITATION. APPARENTLY THIS IS DUE TO
A ZONE OF ISENTROPIC LIFT AHEAD OF A SHORTWAVE TROUGH CROSSING
NORTHWEST ONTARIO. FOR NOW HAVE NOT INCLUDED ANY PRECIPITATION
CHANCES...GIVEN THE DRY 07.00Z/07.12Z CANADIAN AND 07.06Z/07.12Z
GFS...BUT IT IS SOMETHING TO WATCH.
FOR THURSDAY NIGHT INTO SATURDAY...HAVE DISCOUNTED THE 07.06Z GFS AS
AN OUTLIER AND FOLLOWED CLOSER TO THE 07.00Z ECMWF...WITH ITS
SUPPORT FROM THE 07.00Z GFS ENSEMBLES AND 06.12Z ECMWF ENSEMBLES.
THE 07.12Z GFS CAME IN LOOKING CLOSER TO THE 07.00Z ECMWF...
SUPPORTING THE FORECAST PLAN. HOWEVER...IT SHOULD BE NOTED THAT
THE THE ECMWF ENSEMBLES DO SHOW QUITE A BIT OF SPREAD ON SATURDAY SO
CONFIDENCE NEXT WEEKEND IS LOW. IN ANY EVENT...THE IDEA FOR THE
UPPER LEVEL PATTERN IS FOR THE WESTERN TROUGH TO GRADUALLY PUSH EAST
AND EJECT OUT...WHILE SIMULTANEOUSLY ANOTHER SHORTWAVE TROUGH DIGS
ACROSS SOUTHEAST CANADA. A FRONTAL BOUNDARY ASSOCIATED WITH THIS
NORTHERN STREAM SHORTWAVE IS PROGGED TO SLOWLY CROSS THE AREA FRIDAY
AND SATURDAY. THE SLOWNESS IS MOSTLY DUE TO THE BOUNDARY PARALLEL TO
THE UPPER FLOW. AHEAD OF THE BOUNDARY...PLAN ON MILD AND DRY
CONDITIONS WITH LACK OF FORCING AND 850MB TEMPS RUNNING 6-8C. BEHIND
THE BOUNDARY... FRONTOGENESIS WILL HELP DEVELOP CLOUDS AND
PRECIPITATION...KEEPING TEMPERATURES COOLER. AT THIS TIME...ONLY
FORECASTING LOW PROBABILITIES OF PRECIPITATION BEHIND THE BOUNDARY
GIVEN THE UNCERTAIN PATTERN. NEW 07.12Z ECMWF IS A BIT FASTER WITH
THE FEATURES FOR THIS TIME PERIOD...REFLECTING THE UNCERTAINTY.
&&
.AVIATION...REST OF THIS AFTERNOON THROUGH SUNDAY
NO APPRECIABLE AVIATION CONCERNS THROUGH 18Z SUNDAY...WITH ONLY SOME
HIGH CLOUDS MOVING IN DURING THE OVERNIGHT HOURS...AHEAD OF AN AREA
OF LOW PRESSURE APPROACHING FROM THE PLAIN STATES. EXPECT VFR
CONDITIONS THROUGH 18Z.
THE 07.12Z GFS/NAM WANT TO BRING IN A CONSIDERABLE AMOUNT OF LOW
LEVEL SATURATION BY 18Z SUN...WHICH WOULD LINGER OVER THE TAF SITES
THROUGH 12Z MON. THE IMPLICATIONS WOULD BE MVFR/IFR CEILINGS...WITH
POSSIBLY 3-5 SM BR. THIS WOULD BE ASSOCIATED WITH THE LOW SHIFTING
NORTHEAST ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...AND A SLOPING
WARM FRONT. CONFIDENCE A LITTLE SHAKY ON THE MODELS/ ROBUST LOW
LEVEL RH...AS THEY DID POORLY WITH THIS A DAY AGO. HOWEVER...THERE
WILL BE DYNAMICS AND A MORE FAVORABLE SETUP FOR LOW STRATUS
DEVELOPMENT IN THIS STEAD...AND THAT ADDS SOME CREDIBILITY TO THE
MVFR/IFR POTENTIAL. LATER TAF ISSUANCES WILL HAVE TO ADDRESS THIS.
AS FOR PCPN CHANCES...THE DEEPER MOISTURE...THERMODYNAMICS AND UPPER
LEVEL ENERGY WILL BE ACROSS NORTHERN SECTIONS OF MN/WI...AND THIS IS
WHERE THE BETTER LIGHT RA- CHANCES WILL LIE. IF THE LOW STRATUS
SHOULD DEVELOP OVER KRST/KLSE SUNDAY AFTERNOON/EVENING...THERE
APPEARS TO BE ENOUGH ISENTROPIC UPGLIDE THROUGH THIS LAYER THAT
DRIZZLE WOULD BE POSSIBLE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT/LONG TERM...AJ
AVIATION..........REICK
000
FXUS63 KMKX 070927
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
327 AM CST SAT NOV 7 2009
.DISCUSSION...FORECAST FOCUS IS ON MILD TEMPS WITH NEXT CHANCE OF
ANY LIGHT RAIN LATE IN WEEKEND AND INTO EARLY NEXT WEEK.
TODAY-
WATER VAPOR/RUC COMBO SHOWS VORT MAX MOVING INTO WESTERN WI AND
MOVING ENE. A SHIELD OF HIGH CLOUDS ASSOCIATED WITH THIS FEATURE
SHIFTING EAST OF WI PRETTY QUICK. THERMAL RIDGE INTO SRN WI THIS
MORNING WITH TROUGH PASSAGE BRINGING A SHIFT TO A COLD AIR
ADVECTION REGIME AT 850 MILLIBARS. HOWEVER 925 TEMPS REMAIN WARM
ALL DAY AND WITH NO CLOUDS TO HINDER INSOLATION TEMPS WILL
CERTAINLY ZOOM WELL THROUGH THE 60S AND A FEW LOW 70S POSSIBLE AS
WELL.
TONIGHT-
850 MILLIBAR RIDGE AXIS TRANSLATES ACROSS THE CWA WITH NW WINDS
BECOMING SOUTHERLY AND SETTING UP A WARM AIR ADVECTION REGIME. THE
LOW LEVEL RH FIELD SHOWS AXIS OF HIGHEST MOISTURE FROM CENTRAL IL
INTO CENTRAL IA BY 12Z SUNDAY...SO WITH THE COLUMN OTHERWISE
DRY...SEE NO REASON TO NOT GO CLEAR.
SUNDAY-
THINGS GET TRICKIER IN THE HANDLING OF POPS/TEMPS AND CLOUD TRENDS.
EAST/WEST ORIENTED SURFACE FRONT LIFTS NORTH WITH 850 BAROCLINIC
ZONE LIFTING ACROSS THE CWA. AXIS OF HIGHER DEW POINTS AT 850 SHIFTS
NORTHEAST AS THE DAY WEARS ALONG WITH SOMEWHAT DRIER AIR ADVECTING
IN DURING THE AFTERNOON. MEAN RH PROGS PUSH THE HIGHER RH INTO
NORTHERN WI. OVERALL SOUNDINGS/RH SUGGEST AT LEAST SOME
CLOUD/STRATUS POTENTIAL. WITH THE NAM DOING THE BETTER JOB OF LATE
WITH THE LOW LEVEL RH FIELDS PREFER THE NAM MOS SOLUTION. THE GFS
QPF HAS ALSO BEEN OUT TO LUNCH LATELY SO THE NAM QPF IS PREFERRED.
EVEN THO THE GFS SHOWS LIGHT QPF THE MOS GUIDANCE IS IN THE SINGLE
NUMBERS AND WILL CHOOSE TO GO THAT ROUTE. BUT WILL NEED TO MONITOR
TRENDS FOR DRIZZLE SHOULD THE STRATUS ACTUALLY EVOLVE. FOR NOW WILL
GO WITH HIGH CONFIDENCE CLOUDS BUT KEEP THE PRECIP MENTION OUT OF
FORECAST.
MONDAY-
SURFACE LOW LIFTS NORTHEAST DRAGS THE SURFACE AND 850 FRONT THROUGH
THE CWA. THE NAM IS MOST AGGRESSIVE BLOSSOMING THE QPF. THE CANADIAN
IS COMPLETELY DRY. THE GFS IS NOT SHOWING MUCH AT ALL. WILL KEEP THE
CHANCE IDEA IN PLACE.
TUESDAY-
MID LEVEL SHORT WAVE SHIFTS INTO EASTERN GREAT LAKES WITH
ANTICYCLONIC VORTICITY ADVECTION IN THE WAKE. SURFACE AND 850
MILLIBAR HIGH PRESSURE RIDGE GRADUALLY SHIFTS OVER SOUTHERN WI LATER
IN THE DAY. 850 COOL POOL LINGERS.
WEDNESDAY-
SURFACE AND 850 RIDGE AXES SHIFT TO OUR EAST. WARM AIR ADVECTION
RETURNS WITH THIS INTERCEPTING A 700/500 RIDGE RIDER BUT WELL NORTH
OF THE CWA SO THE DRY LOOK STILL APPEARS ON TRACK AT THIS POINT.
&&
.AVIATION...SO FAR SO GOOD WITH NO STRATUS DEVELOPMENT WITHIN MILD SOUTHWEST
FLOW REGIME AHEAD OF APPROACHING FRONT. SOME STRATUS NOTED OVER
MICHIGAN BUT NOTHING YET WITHIN WARM/MOIST AXIS FROM KS/MO THROUGH
IA AND WI. GFS AND NAM HINT AT MVFR DECK TRYING TO FORM IN THE
12-15Z RANGE BUT IT LOOKING MORE LIKE THIS WOULD BE PATCHY AND
PROBABILITY AT ANY ONE TAF SITE PRETTY LOW.
LOW LEVEL WIND SHEAR SHOULD RELAX THIS MORNING AS 50 KNOT FLOW JUST
OFF THE SURFACE WEAKENS RAPIDLY.
FRONT STALLS AND WEAKENS THIS AFTERNOON AND TONIGHT...AND THEN
RETURN SOUTHERLY FLOW BEGINS AGAIN AHEAD OF NEXT SYSTEM FOR SUNDAY
AND MONDAY. STRATUS FORMATION IS AGAIN POSSIBLE SUNDAY AFTER 12Z
AND WILL HINT AT THIS IN MKE 30 HOUR TAF.
&&
.MARINE...GRADIENT DECREASING RAPIDLY THIS MORNING WITH FLOW
GOING TO WESTERLY AND EVENTUALLY NORTHWEST. WAVES SHOULD TAKE A
WHILE TO DECREASE AND SHOULD NOT DROP BELOW 4 FEET UNTIL 18Z SO
CURRENTLY EXPIRATION OF SMALL CRAFT ADVISORY AT 18Z LOOKS GOOD.
MARGINAL EVENT POSSIBLE WITH SOUTHERLY FLOW REGIME THURSDAY WITH 15
TO 20 KNOT WINDS EXPECTED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR LMZ643>646.
&&
$$
SHORT/LONG TERM...COLLAR
AVIATION/MARINE...CRAVEN
000
FXUS63 KGRB 070910
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
310 AM CST SAT NOV 7 2009
.SYNOPSIS...RELATIVELY LOW AMPLITUDE FLOW EXPECTED FOR THE FCST
PERIOD. MEAN TROF POSN WL BE W OF THE AREA...WITH MEAN RIDGE POSN TO
THE E. LOOKS LIKE THERE WE AN INCREASED TENDENCY FOR SOME SPLITTING
OF THE LOW DURING THE LATTER HALF OF THE PERIOD. THE PATTERN WL KEEP
MILD PACIFIC AIR STREAMING ACRS THE RGN...AND RESULT IN ABV NORMAL
TEMPS. PCPN CHCS WL BE PRIMARILY TIED TO SYSTEMS COMING ACRS EARLY
AND LATE IN THE WEEK.
&&
.SHORT TERM...TDA/TNGT/SUN. VERY MILD AIR NOW PUSHING ACRS THE AREA.
GROUND TEMPS HAVE APPARENTLY WARMED ENOUGH AND THERE HAS BEEN
ENOUGH WIND TO KEEP FG/ST AT BAY. BUT GRADIENT WL WEAKEN SOME BY
SUNRISE...SO FG/ST ACRS MN COULD STILL EXPAND INTO MAINLY THE NRN
PART OF THE FCST AREA FOR A TIME. THAT SHOULD GET SCOURED OUT
FAIRLY QUICKLY AS WEAK COOL FRONT PUSHES THROUGH THE AREA LATER
THIS MORNING. ALTHOUGH 850 MB TEMPS WL START TO FALL BACK THIS
AFTN...THE AIR BEHIND THE FRONT IS OF PACIFIC ORIGIN AND REALLY
QUITE WARM. HIGHS REACHED INTO THE 70S OVER THE WRN PLAINS YDA. SO
EXPECT THE WLY FLOW AND SUBSIDENCE BEHIND THE FRONT COMBINED WITH
VERY WARM START TO THE DAY WILL ALLOW WARM TEMPS TO BE REACHED
ACRS THE FCST AREA. TOOK MAX TEMPS UP A FEW DEGREES...AND INTO THE
60S ALMOST ALL AREAS.
WINDS WILL DIE OFF QUICKLY TNGT AS SML SFC HIGH BUILDS ACRS THE RGN.
SHOULD BE PRETTY GOOD RADIATIONAL COOLING CONDITIONS...THOUGH
SOME CLOUDS SHOULD START TO ARRIVE LATER IN THE NGT. PUSHED MINS
DOWN TOWARD THE COOLEST OF THE GUID TEMPS.
ISENT LIFT WL SPREAD ACRS THE AREA SUN AS THE BOUNDARY STARTS
BACK NWD IN RESPONSE TO CYCLOGENESIS OUT IN THE PLAINS. AIR MASS
INITIALLY QUITE DRY...SO IT WL TAKE A LOT OF LIFT TO ACHIEVE
SATURATION. CON/T CHC POPS ACRS THE NW PART OF THE AFTN AS THAT
AREA HAS THE BEST CHC OF SEEING PCPN. ECMWF GENERATED VERY LGT
PCPN ACRS MOST OF THE REMAINDER OF THE FCST AREA DURING THE DAY.
THAT PCPN APPEARED TO BE SPRINKLES OUT OF MIDDLE CLOUD DECK SHIFTG
NWD ALONG EDGE OF VERY STEEP MIDDLE LEVEL LAPSE RATES THAT SHOULD
BE SPREADING IN FM THE S. DECIDED TO GO WITH CHC OF SPRINKLES ACRS
MOST OF THE REST OF THE AREA DURING THE AFTN. IF PCPN IS SPRINKLES
OUT OF MID- DECK...IT COULD BEGIN A LITTLE EARLIER. BUT DIDN/T
HAVE ENOUGH CONFIDENCE TO PULL PCPN BACK INTO MORNING HOURS YET.
USED BLEND OF THE VARIOUS BIAS-CORRECTED GUID PRODUCTS FOR MAX
TEMPS...THEN LOWERED LAKESHORE A BIT DUE TO DEVELOPING ELY FLOW.
.LONG TERM...SUNDAY NGT THRU NXT FRI. NO MAJOR SYSTEMS ON THE
HORIZON DURING THE PERIOD AS A NEARLY ZONAL FLOW CONTS TO BRING
WARM...PACIFIC AIRMASS INTO NE WI. MAIN FCST CONCERNS TO BE TIMING
OF A WEAK SYSTEM COMING THRU SUNDAY NGT INTO MON...AND THEN MDL
DIFFERENCES WITH RESPECT TO THE HANDLING OF UPR JET BRANCHES LATE
NXT WEEK. TEMPS FOR THE MOST PART WL BE RUNNING 5 TO 10 DEGS ABV
NORMAL NXT WEEK.
THE WRMFNT REACHES INTO CNTRL/E-CNTRL WI SUNDAY EVENING...BUT IS
QUICKLY FOLLOWED BY A WEAK CDFNT WHICH IS FCST TO PUSH INTO CNTRL
SECTIONS OF WI BY 12Z MON. A SFC WAVE IS EXPECTED TO RIDE NE ALONG
THE CDFNT AND BE IN OUR GENERAL VCNTY AFT MIDNGT. THESE FNTL
BOUNDARIES AND SFC WAVE WL COMBINE WITH WEAK TO MODERATE FORCING
AND FAVORABLE UPR JET DYNAMICS TO PRODUCE A CHC OF LGT RAIN ACROSS
THE ENTIRE FCST AREA. HAVE INCLUDED SOME AREAS OF FOG AS PLENTIFUL
LOW-LVL MSTR TO BE IN PLACE AND SFC TEMPS/DEW PTS TO BE AT ALMOST
COMPLETE SATURATION. A MILD NGT ON TAP WITH MIN TEMPS GENERALLY IN
THE LWR TO MIDDLE 40S.
CDFNT COMPLETES ITS PASSAGE THRU THE FCST AREA MON MORNING...THUS
LINGERING CHC POPS ARE NECESSARY FOR ALL BUT N-CNTRL WI. BY MON
AFTERNOON...SOME DRIER AIR WL BEGIN TO ADVECT INTO NW WI AND ALLOW
FOR SOME BREAKS IN THE CLD CVR OVR N-CNTRL WI. THE REST OF THE
AREA WL STILL HAVE A GOOD DEAL OF CLDS AS MSTR HANGS AROUND BEHIND
THE CDFNT. TEMPS TO SETTLE BACK INTO THE 50S ON MON...BUT THIS IS
STILL 5 TO 10 DEGS ABV NORMAL.
A BROAD AREA OF HI PRES IS THEN SET TO BUILD TOWARD THE WRN GREAT
LKS RGN MON NGT AND BRING A GENERAL DECREASE IN CLDS TO NE WI.
CLDS SHOULD CLR N-CNTRL AND PARTS OF CNTRL WI FIRST WHICH WL ALLOW
TEMPS TO DROP OFF WELL DOWN INTO THE 30S. E-CNTRL WI TO SEE ANY
CLEARING LAST (PERHAPS NOT TIL THE WEE HRS OF THE MORNING)...THUS
MIN TEMPS TO HOLD IN THE UPR 30S TO AROUND 40 DEGS. THE HI PRES
REACHES THE WI/MN/IA VCNTY ON TUE BRINGING PLENTY OF SUNSHINE TO
THE RGN. NE WI TO STILL BE ON THE "COOL" SIDE OF THE HI...THUS MAX
TEMPS TO BE RELEGATED TO THE UPR 40S TO LWR 50S.
AS THE HI PRES SLIPS OFF TO OUR EAST ON WED...A RETURN FLOW WL
GRADUALLY DVLP ACROSS WI. BEST WAA REMAINS TO THE WEST DURING THE
DAY AND WITH THE EXPECTED COOL START TO THE DAY...MAX TEMPS WL BE
HELD IN CHECK. HAVE KEPT TEMPS BLO THE MEX GUID AS THE GFS APRS
TOO QUICK WITH THE WARM-UP.
FCST BECOMES A BIT MORE MUDDLED FROM WED NGT ONWARD AS THE MDLS
ARE STRUGGLING WITH THE DEGREE OF INTERACTION BETWEEN THE NRN AND
SRN BRANCHES OF THE UPR JET. MORE SEPARATION WOULD ALLOW FOR A
FASTER MOVEMENT OF A CDFNT TOWARD THE WRN GREAT LKS RGN ON THU...
WHILE LESS SEPARATION WOULD DELAY THE MOVEMENT OF THE CDFNT.
ENSEMBLE OUTPUT ALSO SHOW QUITE A RANGE OF POSSIBILITIES...THEREFORE
HAVE LEFT THU`S FCST ALONE WITH THE BEST CHC OF SEEING ANY PCPN OVR
N-CNTRL WI. TIMING OF THIS CDFNT BECOMES PROBLEMATIC DEPENDING ON
HOW THE JET BRANCHES PLAY OUT. APRS THAT AT LEAST OF CHC OF LGT
RAIN IS NEEDED FOR THU NGT AND PERHAPS EVEN INTO FRI. FOR NOW...
HAVE LET THE PREV FCST RIDE AND WAIT FOR BETTER MDL CONTINUITY.
&&
.AVIATION...UNLESS SOME IFR CONDITIONS CAN DEVELOP OVER THE N BY
SHORTLY AFTER DAYBREAK...EXPECT VFR CONDITIONS TDA AND TNGT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SKOWRONSKI/KALLAS
000
FXUS63 KARX 070840
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
240 AM CST SAT NOV 7 2009
.SHORT TERM...TODAY THROUGH MONDAY
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SUNDAY AFTERNOON
INTO MONDAY.
LATEST 07Z SURFACE ANALYSIS INDICATED WEAK COLD FRONT EXTENDING
FROM WESTERN MINNESOTA INTO EASTERN NEBRASKA. OUT AHEAD OF THE
FRONT...A SOUTH TO SOUTHWEST WINDS HAVE ALLOWED TEMPERATURES TO
BE MILD WITH READINGS IN THE UPPER 40S TO THE UPPER 50S ACROSS
FORECAST AREA PER LATEST METARS. WITH THE LACK OF MOISTURE WITH
SURFACE FRONT...HIGH CLOUDS WERE PRESENT OVER NORTHERN WISCONSIN
AND NORTHEAST MINNESOTA AND MOSTLY CLEAR SKIES WERE SEEN ELSEWHERE
PER LATEST LOW CLOUD/FOG SATELLITE IMAGERY.
THE 07.00Z GFS AND NAM ARE IN GOOD AGREEMENT WITH FAST WEST TO EAST
ZONAL UPPER LEVEL FLOW ACROSS CONTINENTAL U.S. THROUGH THE FORECAST
PERIOD. BOTH THE MODELS IN GOOD AGREEMENT IN MOVING SURFACE
COLD FRONT ACROSS THE FORECAST AREA TODAY AND BUILDING SURFACE
RIDGE INTO UPPER MIDWEST TONIGHT. THEN...THE DETERMINISTIC
07.00Z GFS AND NAM BEGIN TO DIFFER ON AMOUNT OF MOISTURE
ASSOCIATED WITH SURFACE/850MB WARM FRONT SUNDAY...AND TIMING OF THE
SHORTWAVE TROUGH/SURFACE FRONT INTO FORECAST AREA MONDAY. WITH
THE 07.00Z GFS MORE ROBUST WITH MOISTURE WITH SURFACE WARM FRONT AND
MORE PROGRESSIVE WITH SHORTWAVE TROUGH/SURFACE FRONT MONDAY.
TODAY AND TONIGHT...WEAK SURFACE COLD FRONT MOVES ACROSS FORECAST
AREA BY 18Z SATURDAY. DUE TO THE LACK OF MOISTURE AND WEAK LIFT ALONG
SURFACE FRONT...THE FORECAST AREA WILL REMAIN DRY AND A FEW HIGH
CLOUDS ARE ANTICIPATED. WITH DRY AIRMASS IN PLACE ACROSS
FORECAST AREA AND CURRENT MORNING TEMPERATURES MILD...HAVE RAISED MAX
TEMPERATURES FOR TODAY. SURFACE RIDGE BUILDS INTO FORECAST AREA BY
00Z SUNDAY. BOTH THE 07.00Z GFS AND NAM INDICATE SUBSIDENCE
UNDERNEATH RIDGE PER BUFKIT FORECAST SOUNDINGS AND TIME HEIGHT CROSS
SECTIONS. DRY WEATHER CONDITIONS WILL CONTINUE INTO TONIGHT ACROSS
FORECAST AREA.
FOCUS THEN TURNS TO APPROACHING SURFACE/850MB WARM FRONT AND
COLD FRONT SUNDAY INTO MONDAY. BOTH THE 07.00Z GFS AND NAM ARE
INDICATING INCREASING LOW LEVEL MOISTURE ALONG AND NORTH OF SURFACE
WARM FRONT...AS WARM FRONT MOVES NORTH FROM THE CENTRAL PLAINS
STATES INTO SOUTHERN MINNESOTA AND CENTRAL WISCONSIN BY 18Z SUNDAY.
BOTH THE MODELS ARE INDICATING THE BEST AND DEEPER SATURATION OCCURS
OVER THE NORTHERN HALF OF THE FORECAST AREA...WHERE THE BETTER
ISENTROPIC LIFT...MOISTURE TRANSPORT AND CONVERGENCE IS LOCATED. HAVE
FOCUSED PRECIPITATION CHANCES OVER NORTHERN HALF OF FORECAST AREA AND
TAKEN PRECIPITATION CHANCES OUT OVER THE SOUTHERN HALF AFTER 18Z
SUNDAY.
SURFACE COLD FRONT AND ASSOCIATED SHORTWAVE TROUGH TRACKS INTO
NORTHEAST WISCONSIN AND CENTRAL IOWA BY 12Z MONDAY. WEAK SURFACE
LOW MOVES ALONG THE FRONT AND OVER THE FORECAST AREA BY 06Z MONDAY.
BOTH THE 07.00Z GFS AND NAM CONTINUE TO INDICATE ENOUGH VERTICAL
MOTION WITH WEAK SURFACE LOW...THOUGH MODELS CONTINUE TO HINT AT
SATURATION UP TO 800MB PER BUFKIT FORECAST SOUNDINGS. CONFIDENCE IN
MEASURABLE PRECIPITATION ACROSS FORECAST AREA SUNDAY NIGHT IS LOW...
BASED ON DETERMINISTIC MODEL TRENDS OF LACK OF DEEP SATURATION...
HENCE LIGHT QPF AMOUNTS ACROSS FORECAST AREA. WILL CONTINUE WITH
SMALL CHANCES OF PRECIPITATION ACROSS FORECAST AREA SUNDAY NIGHT.
BOTH THE 07.00Z GFS AND NAM DO INDICATE BETTER FORCING...LIFT AND
MOISTURE AFTER 18Z MONDAY ALONG SURFACE COLD FRONT...THOUGH MODELS
ARE OFF ON PLACEMENT AND TIMING OF SURFACE COLD FRONT PASSAGE
THROUGH FORECAST AREA. THE GFS IS INDICATING SURFACE COLD FRONT
SOUTH AND EAST OF FORECAST AREA BY 00Z TUESDAY AND NAM INDICATES
SURFACE COLD FRONT OVER THE EXTREME SOUTHEASTERN PORTIONS OF THE
FORECAST AREA. FOR NOW...HAVE TAKEN A BLEND OF BOTH THE MODELS AND
CONTINUE WITH PREVIOUS FORECAST TRENDS OF PRECIPITATION CHANCES OVER
THE SOUTHEASTERN PORTION OF FORECAST AREA MONDAY.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THURSDAY AND
THURSDAY NIGHT. THE 07.00Z GFS AND ECMWF ARE IN GOOD AGREEMENT IN
BUILDING UPPER LEVEL RIDGE INTO THE UPPER MIDWEST AND GREAT LAKES
REGION TUESDAY THROUGH WEDNESDAY NIGHT...THEN BEGIN TO DIVERGE ON
TIMING UPPER LEVEL SHORTWAVE TROUGH INTO THE NORTHERN PLAINS THURSDAY
INTO THURSDAY NIGHT...AS THE 07.00Z GFS IS MORE PROGRESSIVE THAN THE
ECMWF. AT THIS TIME...WILL MAKE NO CHANGES TO PREVIOUS FORECAST AND
LET LATER SHIFTS TO DIAGNOSE TIMING OF SHORTWAVE TROUGH/SURFACE
FEATURES INTO FORECAST AREA THURSDAY AND THURSDAY NIGHT.
&&
.AVIATION...TODAY AND TONIGHT
VFR CONDITIONS EXPECTED TO CONTINUE TODAY THROUGH TONIGHT. ABOUT THE
ONLY EFFECT OF A PACIFIC COLD FRONTAL PASSAGE EARLY THIS MORNING
WILL BE A WIND SHIFT TO THE NORTHWEST. FRONT BECOMES NEARLY
STATIONARY SOUTH OF THE AREA TONIGHT...AS LOW PRESSURE BEGINS MOVING
OUT INTO THE CENTRAL PLAINS. CLOUDS AHEAD OF THIS SYSTEM SHOULD
SPREAD IN DURING THE OVERNIGHT...WITH CEILINGS AT OR ABOVE 12KFT.
LOOKING AHEAD...CONFIDENCE WAS GROWING BASED ON CONSISTENCY IN
FORECAST GUIDANCE THAT MVFR/IFR CONDITIONS IN LIGHT RAIN/FOG COULD
IMPACT AIRPORTS SUNDAY AFTERNOON INTO MONDAY AS LOW PRESSURE PULLS
THE FRONT BACK INTO THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT/LONG TERM...DTJ
AVIATION..........THOMPSON
| 
