Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 261818 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
118 PM CDT TUE MAY 26 2015

.UPDATE...

A LEADING... STRONG MID LEVEL SHORTWAVE IS DIGGING INTO SOUTHERN WI
TODAY. THIS IS SUPPORTED BY LEFT EXIT REGION OF THE UPPER JET AND
THE NOSE OF THE LOW LEVEL JET. A BAND OF MODERATE RAIN WITH A WARM
FRONT IS PROPAGATING NORTH-NORTHEAST FROM THE CENTER OF THE VORT MAX
THAT IS NOW STATIONED IN SOUTHEAST WI.

THERE IS NOT A LOT OF LIGHTNING IN THIS BAND OF RAIN SINCE MID LEVEL
LAPSE RATES ARE VERY WEAK SO THERE IS MINIMAL CAPE. THERE IS STRONG
0-1KM AND 0-6KM BULK SHEAR. RADAR IS SHOWING EMBEDDED STRONGER CELLS
THAT FEATURE WEAK ROTATION DUE TO THIS HIGH-SHEAR-LOW-CAPE
ENVIRONMENT. THIS ENVIRONMENT SUPPORTS AN ISOLATED SEVERE CONCERN
FOR BRIEF TORNADO SPIN-UPS AND WE ARE CLOSELY MONITORING THE RADAR.

EASTERN WISCONSIN IS HIGHLIGHTED IN A SLIGHT RISK FOR SEVERE WEATHER
TODAY FROM SPC. A RECENT MESOSCALE DISCUSSION FOCUSED IN ON THIS
AREA THAT HAD MORNING CLEARING IN EAST CENTRAL WI WHERE SURFACE AND
MIXED LAYER CAPE VALUES BUILT INTO 500-1000 J/KG LATE IN THE
MORNING. THIS AREA OF HIGHER CAPE IS SHIFTING NORTH EARLY THIS
AFTERNOON.

PRECIPITABLE WATER VALUES ARE OVER 1.5 INCHES SO THE MAIN CONCERN
TODAY IS HEAVY RAIN WHICH COULD BE A PROBLEM IN URBAN AREAS.

THE MAIN SHORTWAVE/ VORT MAX IS LOCATED OVER EAST CENTRAL IOWA AS OF
1 PM AND MAY PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AS
IT TRACKS THROUGH SOUTH CENTRAL WI THIS AFTERNOON AND EVENING.
SOUTHERN WI SHOULD HAVE DRY WEATHER AFTER MIDNIGHT INTO MID
WEDNESDAY MORNING... ALTHOUGH I CAN/T RULE OUT A STRAY SHOWER OR TWO
IN THIS MOIST ENVIRONMENT.

SOUTHERLY WINDS WILL BEGIN INCREASING IN THE WAKE OF THE RAIN BAND
EARLY THIS AFTERNOON. EXPECT GUSTY SOUTHWEST WINDS LATER THIS
AFTERNOON INTO THIS EVENING. WINDS WILL DIMINISH AFTER MIDNIGHT AS
THEY SHIFT TO THE WSW.

&&

.AVIATION/18Z TAFS/...

A BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS WILL LIFT NORTH-
NORTHEAST THROUGH SOUTH CENTRAL AND SOUTHEAST WISCONSIN EARLY THIS
AFTERNOON AS LOW PRESSURE SLOWLY TRACKS THROUGH THE REGION. LOOK FOR
A BREAK IN PRECIP FROM SOUTH TO NORTH DURING THE EARLY AFTERNOON...
THEN SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE DURING THE LATE
AFTERNOON AND EVENING HOURS.

GUSTY SOUTHERLY WINDS ARE FORECAST FOR THE AFTERNOON. THEY WILL
GRADUALLY SHIFT TO THE SOUTHWEST BY LATE AFTERNOON. EXPECT WIND
GUSTS TO PERSIST UNTIL AROUND MIDNIGHT UNTIL THE WINDS SHIFT TO THE
WEST.

AREAS OF 1.0-3.0 KFT CIGS WILL OCCUR AT TIMES AS MOIST AIR FLOWS
INTO SRN WI WITH VSBYS REDUCTIONS WITHIN PRECIPITATION. WLY FLOW
WILL BRING DRIER CONDITIONS FOR WED.

&&

.MARINE...

DENSE FOG DEVELOPED OVER THE NEARSHORE WATERS NEAR SHEBOYGAN AND
EXPANDED SOUTH LATE IN THE MORNING. DENSE FOG ADVY IN EFFECT.
CONDITIONS SHOULD IMPROVE FROM SOUTH TO NORTH AS SOUTH TO SOUTHWEST
WINDS INCREASE DURING THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 515 AM CDT TUE MAY 26 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.

AN OUTFLOW BOUNDARY IS SLOWLY MOVING EWD INTO SOUTH CENTRAL WI EARLY
THIS AM. THIS WILL LIKELY CONTINUE TO TRIGGER AT LEAST ISOLD SHOWERS
OR TSTORMS THROUGH THE MORNING. THE UPPER TROUGH CURRENTLY MOVING
TOWARD THE MIDDLE MS RIVER VALLEY WILL THEN SWING NWD THROUGH SRN WI
THIS AFTERNOON WITH A WAVE OF LOW PRESSURE TO TRACK ACROSS ERN IA
INTO C WI BY 00Z WED. THE LEADING EDGE OF PVA AND THE NOSE OF A
DEVELOPING SLY LLJ WILL MOVE INTO THE REGION FROM THE MIDDLE TO LATE
MORNING HOURS INTO THE AFTERNOON. PWS WILL INCREASE TO 1.5 INCHES
DURING THIS TIME WITH TALL AND SKINNY CAPE ON THE FCST SOUNDINGS.
HIGH POPS ARE FORECAST FOR THE SHOWERS/TSTORMS TODAY WITH HEAVY
RAINFALL RATES AT TIMES. ONLY CHANCES OF PCPN TNT AS THE SYSTEM
MAINLY MOVES TO THE NORTH AND A WEAK COOL FROPA OCCURS. THE MLCAPE
TODAY WILL LIKELY STAY BELOW 500 J/KG GIVEN THE EARLY ARRIVAL OF
CLOUDS/PCPN AS WELL AS POOR MID LEVEL LAPSE RATES. THUS THE SEVERE
TSTORM THREAT IS MINOR DESPITE MDT DEEP LAYER AND LOW LEVEL SHEAR
DEVELOPING.

WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM

A SHORTWAVE WILL MOVE THROUGH SOUTHERN WISCONSIN WEDNESDAY
MORNING...DEPARTING THE FORECAST AREA EARLY AFTERNOON. WILL
PROBABLY SEE A FEW SHOWERS AND STORMS AS THE WAVE MOVES
THROUGH...MAINLY DURING THE MORNING HOURS. A DRIER AIRMASS WILL
MOVE IN BEHIND THE WAVE...LIKELY BRINGING DECREASING CLOUDS WEST
TO EAST DURING THE AFTERNOON. ADDITIONALLY...TEMPS ALOFT WILL
RECOVER BEHIND THE WAVE TO AROUND 18-20C AT 925 MB BY LATE
AFTERNOON. THIS WILL ALLOW TEMPS TO CLIMB TOWARD 80 WEST...WITH
SOMEWHAT COOLER TEMPS EAST WITH THE CLOUDS EXITING LATER.

DRY WEATHER IS EXPECTED WEDNESDAY NIGHT AND THURSDAY AS SHORTWAVE
RIDGING BUILDS INTO THE AREA FOR A SHORT TIME. ABOVE NORMAL HIGH
TEMPS ARE LIKELY THURSDAY...THOUGH TEMPS WILL BE SOMEWHAT COOLER
NEAR LAKE MICHIGAN UNDER PERSISTENT SOUTHEAST WINDS.

A CHANCE FOR SHOWERS AND THUNDERSTORMS WILL RETURN FOR THURSDAY
NIGHT...AS 850-700 MB WARM ADVECTION INCREASES ALONG WITH
INCREASING MOISTURE.

SHOWERS AND STORMS ARE LIKELY FRIDAY AND FRIDAY NIGHT AS A
SHORTWAVE MOVES THROUGH WHILE A COLD FRONT DROPS SOUTHWARD INTO
THE AREA. ABOVE NORMAL TEMPS ARE EXPECTED TO CONTINUE.

SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...LOW

MODELS DIVERGE FOR SATURDAY THROUGH MONDAY. THE GFS KEEPS A SLOW
MOVING UPPER LOW AND ASSOCIATED SURFACE LOW CLOSE TO THE FORECAST
AREA RIGHT THROUGH MONDAY...BRINGING PERSISTENT SHOWER CHANCES.
THE ECMWF AND CANADIAN SOLUTIONS HAVE HIGH PRESSURE BUILDING IN
QUICKER AND SHOVING THE LOW FARTHER SOUTH. THESE MODELS WOULD
RESULT IN DRY WEATHER FROM SATURDAY AFTERNOON THROUGH MONDAY.
CONSENSUS APPROACH TO THE FORECAST RESULTED IN SOME LINGERING POPS
RIGHT THROUGH MONDAY...THOUGH OBVIOUSLY NOT A LOT OF CONFIDENCE IN
PRECIP CHANCES AT THIS POINT.

ONE THINGS THAT LOOKS A BIT MORE CERTAIN IN THE EXTENDED IS THAT
IT WILL TURN COOLER FOR SATURDAY THROUGH MONDAY. GIVEN MODEL
DIFFERENCES THOUGH...IT IS YET TO BE DETERMINED HOW COOL.
HOPEFULLY THE FORECAST TRENDS AWAY FROM THE GFS...WHICH SUGGESTS
TEMPS STRUGGLE IN THE 40S UNDER AN ALL DAY RAIN EVENT SATURDAY.
KEEP YOUR FINGERS CROSSED THAT THE HIGH MOVES IN QUICKER PER THE
ECMWF AND CANADIAN.

AVIATION/12Z TAFS/...SHOWER AND TSTORMS WILL OCCUR AT TIMES FROM
LATER THIS MORNING THROUGH THE AFTERNOON AND POSSIBLY THE EVENING AS
LOW PRESSURE PASSES THROUGH THE REGION. AREAS OF 1.0-3.0 KFT CIGS
WILL OCCUR AT TIMES AS MOIST AIR FLOWS INTO SRN WI WITH VSBYS
REDUCTIONS WITHIN PRECIPITATION. WLY FLOW WILL BRING DRIER
CONDITIONS FOR WED.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LMZ644>646.

     DENSE FOG ADVISORY UNTIL 4 AM CDT WEDNESDAY FOR LMZ643.

&&

$$

UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
WEDNESDAY THROUGH MONDAY...DDV


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