Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 270154
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
854 PM CDT TUE AUG 26 2014

.UPDATE...
SURFACE HIGH PRESSURE WILL KEEP THE AREA QUIET TONIGHT INTO
WEDNESDAY. THE SMALL POPS IN THE FCST TONIGHT INTO WED MORNING ACROSS
THE FAR SOUTH HAVE BEEN CUT OUT OF ALL BUT THE FAR SOUTHWEST
ALREADY AND WILL LIKELY PULL COMPLETELY IF NOTHING OF SUBSTANCE
DEVELOPS OVER IOWA BEFORE MIDNIGHT. THE LATEST SHORT RANGE MODELS
SUGGEST A DRY FORECAST INTO WEDNESDAY NIGHT. LIGHT WINDS COULD
RESULT IN SOME PATCHY FOG OVERNIGHT. NO OTHER CHANGES NEEDED TO
THE GOING FORECAST.

&&

.AVIATION/06Z TAFS/...
OTHER THAN SOME PATCHY FOG OUT IN RURAL AREAS OVERNIGHT...EXPECT
VFR CONDITIONS THROUGH THE TAF PERIOD. KENW IS A MORE RURAL
AIRPORT AND COULD SEE SOME LATE NIGHT FOG...BUT IT SHOULD BE SHORT
LIVED AND NOT VERY HEAVY. WINDS WILL BE NORTHERLY LESS THAN 10
KNOTS THROUGH THE TAF PERIOD. EXPECT A MID LEVEL CLOUD DECK TO
ROLL ACROSS THE AREA TONIGHT INTO WEDNESDAY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 310 PM CDT TUE AUG 26 2014/

TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE - HIGH.

MODELS IN AGREEMENT WITH HIGH PRESSURE SLIDING EAST SOUTHEAST FROM
THE NORTHERN PLAINS INTO THE UPPER PENINSULA OF MICHIGAN DURING THIS
PERIOD. THIS WILL KEEP A DRY AIRMASS ACROSS MOST OF THE AREA.
THUS...KEPT QUIET WEATHER FORECAST GOING FOR MOST OF THE AREA.

KEPT SMALL POPS ACROSS THE FAR SOUTHWEST AND FAR SOUTHERN COUNTIES
LATER TONIGHT...AND THE FAR SOUTHWEST COUNTIES ON WEDNESDAY. RIGHT
REAR QUADRANT OF 250 MB JET STREAK IS EXPECTED TO BRUSH THESE AREAS
LATER TONIGHT INTO WEDNESDAY. MOST OF THE UPPER DIVERGENCE AND BEST
MOISTURE IS TO THE SOUTH AND SOUTHWEST OF THE AREA.

AREA FORECAST SOUNDINGS FROM DUBUQUE IOWA SHOWING MEAGER ELEVATED
CAPES ON NAM...WITH LITTLE TO NONE ON THE GFS. KEPT THUNDER WORDING
FOR NOW...BUT COULD BE REMOVED IN LATER FORECASTS. SHOULD SEE LIGHT
FOG IN MAINLY LOW LYING AREAS LATER TONIGHT AND EARLY WEDNESDAY.

USED BLEND OF SHORT TERM MODELS FOR TEMPERATURES TONIGHT INTO
WEDNESDAY...WITH TEMPERATURES A BIT BELOW SEASONAL NORMALS. ONSHORE
WINDS TUESDAY WILL KEEP LAKESHORE AREAS IN THE LOWER 70S...WITH MID
TO UPPER 70S WELL INLAND.

WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE - MEDIUM.

SHORT TERM GUIDANCE HINTING AT A BIT MORE SHORT WAVE RIDGING LINGERING
OVER SRN WI WEDNESDAY EVENING.  WL CONTINUE DRY EVENING FORECAST BUT THEN
INTRODUCE POPS IN THE WEST AS ALL GUIDANCE IN AGREEMENT ON STRENGTHENING
LOW LEVEL JET FOCUSED INTO MN/WI/IA TRI-STATE AREA BY 12Z.  ECMWF SLIGHTLY
SLOWER WHILE GEM IN BETTER AGREEMENT WITH MORE AGRESSIVE NAM/GFS.
IMPRESSIVE FRONTOGENETICAL RESPONSE TO STRONG WARM AIR ADVECTION ASSOCIATED
WITH LOW LEVEL JET ACROSS TRI-STATE AREA SPREADS RAPIDLY EAST ACROSS CENTRAL
WI THU MORNING.  EXPECT CONVECTION TO SPREAD ACROSS NRN CWA DURING THE MRNG AND
EARLY AFTN SO BEEFED UP POPS TO LIKELY WITH SOME CATEGORICAL IN THE FAR NW.

INITIAL SURGE OF MOISTURE FLUX CONVERGENCE WITH LOW LEVEL JET SHIFTS OFF TO THE
NORTHEAST BY 00Z FRI.  HOWEVER BOTH ECMWF AND GEM SHOW LOW LEVEL JET REFOCUSING
FARTHER SOUTH ACROSS SRN WI THU NGT.  BY THIS TIME...PWAT VALUES WILL HAVE
INCREASED TO AROUND 2 INCHES ONCE AGAIN.  DUE TO RETURN OF LOW LEVEL CONVERGENCE AND
PASSING RIGHT ENTRANCE REGION OF UPPER JET...WL CONTINUE LIKELY WORDING THU NGT
BUT CONFIDENCE NOT GREAT AT THIS TIME THAT WIDESPREAD CONVECTION WILL RETURN.

LACK OF CAP AND INITIALLY UNSTABLE ATMOSPHERE ON FRIDAY WITH WARM FRONT IN THE AREA...
WILL CONTINUE CHANCE POPS BUT LOWER SLIGHTLY AS INCREASING SOUTHWEST
WINDS IN THE LOW LEVELS CARRY DRIER AIR INTO SRN WI.  BEST CHANCE
FOR SEVERE WILL BE LATER THURSDAY INTO THU NIGHT AS ATMOSPHERE
RECOVERS FROM MORNING CONVECTION.  BULK SHEAR INCREASES TO 30 KNOTS
AS DEEPER MOISTURE AND INSTABILITY SURGES IN.

FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE - MEDIUM.

LEANING MORE ON A ECMWF/GEM BLEND FOR THE BULK OF THIS PERIOD DUE TO
BETTER RUN TO RUN CONSISTENCY AND AGREEMENT.  GFS REMAINS OUTLIER...
SHOWING TYPICAL BIAS IN THIS PERIOD OF OVERSTRENGTHENING LOW PRESSUE
SYSTEMS ALONG BAROCLINIC ZONE. WPC ALSO PREFERS MORE PROGRESSIVE
ECMWF AND ECMWF ENSEMBLE BLEND.

ECMWF AND GEM CLOSER IN TIMING OF NORTHERN STREAM AND SOUTHERN
STREAM SHORTWAVES MOVING ACROSS WRN GTLAKES AND SRN CANADA EARLY IN
THE WEEKEND.  WITH LOW PRESSURE AND SEVERAL FRONTAL BOUNDARIES IN
THE AREA AND HIGH COLUMN PWA...WL CONTINUE CHANCE POPS ON SATURDAY
WITH DECREASING TREND SATURDAY NIGHT.  MAY BE ABLE TO REMOVE ANY
POPS FOR SUNDAY AS ALL MEDIUM RANGE GUIDANCE TRENDING TOWARD DRYING
WITH SHORT WAVE RIDGING BUILDING INTO THE WRN GTLAKES.  PERIOD OF
DRY WX WOULD BE BRIEF HOWEVER AS AMPLIFYING LONG WAVE TROUGH OVER
SOUTHWEST CANADA WL BE EXPANDING INTO WRN CONUS OVER THE WEEKEND.
PIECE OF SHORT WAVE ENERGY EJECTED FROM THIS TROUGH WOULD THEN
AFFECT WISCONSIN EARLY NEXT WEEK.  6-10 AND 8-14 DAY 500MB HEIGHTS
VALID NEXT WEEK SHOW UPSTREAM NEGATIVE ANOMOLY SPREADING INTO UPPER
MIDWEST AND DECREASING AS UPPER FLOW BECOMES STRONGLY ZONAL.
HENCE TEMPS LIKELY RETURNING TO NEAR OR SLIGHTLY BELOW NORMAL DURING
THE WEEK FOLLOWING LABOR DAY.

AVIATION/00Z TAFS/...

EXPECT VFR CONDITIONS TONIGHT INTO WEDNESDAY ACROSS TAF SITES. LIGHT
WINDS ARE EXPECTED UNTIL SUNSET. A FEW DIURNAL CUMULUS CLOUDS MAY
DEVELOP. WINDS MAY TURN EAST AT MILWAUKEE AND KENOSHA WITH LAKE
BREEZE BEFORE SUNSET...BUT WILL LEAVE OUT OF TAFS FOR NOW.

HIGH PRESSURE MOVING EAST FROM NORTHERN MINNESOTA TO THE UPPER
PENINSULA OF MICHIGAN TONIGHT AND WEDNESDAY WILL KEEP QUIET WEATHER
OVER MOST THE AREA. THERE SHOULD BE SOME MIDDLE TO HIGH CLOUDS
MOVING INTO THE AREA LATER TONIGHT INTO WEDNESDAY.

ANY FOG SHOULD BE LIMITED TO LOW LYING AREAS AND SHORT LIVED LATER
TONIGHT INTO EARLY WEDNESDAY MORNING. LIGHT WINDS WILL ALSO BECOME
NORTHEAST BY WEDNESDAY AFTERNOON.

HYDROLOGY...

INITIAL SURGE OF STRONG WARM AIR ADVECTION WILL SPREAD SOME HEAVY
RAINFALL EXCEEDING AN INCH ACROSS PORTIONS OF THE CWA ON THU.  DEEP
MOISTURE WILL CONTINUE TO SURGE INTO THE AREA AND ALONG WITH LOW
LEVEL JET REFOCUSING INTO SRN WI...ANOTHER ROUND OF HEAVY RAINFALL
WILL BE POSSIBLE THU NGT.  BY THAT TIME...PWAT VALUES WILL HAVE
INCREASED TO OVER 2 INCHES.  FOR LATE AUGUST...THIS IS APPROACHING
THE 99TH PERCENTILE FOR NRN IL.  WARM CLOUD DEPTH EXCEEDS 10K FEET
BY  THU NGT AND MESO-BETA ELEMENTS LESS THAN 10KTS MUCH OF THE
NIGHT.  HYDROLOGIC OUTLOOK MAY BE ISSUED FOR HEAVY RAINFALL THREAT
IN LATER FORECAST SHIFTS.

&&

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

$$

UPDATE...DAVIS
TONIGHT/WEDNESDAY AND AVIATION/MARINE...WOOD
WEDNESDAY NIGHT THROUGH TUESDAY...MBK


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