Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 270243
AFDMKX

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

.UPDATE...

LOW PRESSURE WILL MOVE SLOWLY ACROSS NORTHEAST WISCONSIN. A FEW
SHOWERS MAY BRUSH MAINLY FAR NORTH AND FAR SOUTHERN AREAS.
BRISK SOUTHWEST WINDS HAVE DIMINISHED OVER MUCH OF THE
AREA...EXCEPT FAR EAST AND NORTHEAST AREAS.

&&

.AVIATION/06Z TAFS/...

SHOWERS MAY BRUSH AREAS NORTH OF THE DELLS TO FOND DU LAC. ALSO
A FEW SHOWERS MAY BRUSH THE ILLINOIS BORDER AREAS.

GUSTY SOUTHWEST WINDS FROM A LOW MOVING ACROSS NORTHEAST WISCONSIN
WILL DIMINISH.

A PERIOD OF MVFR CIGS ARE POSSIBLE TONIGHT THROUGH LATE WEDNESDAY
MORNING AS AN UPPER LEVEL TROUGH SLOWLY MOVES ACROSS THE REGION.
SCATTERED SHOWERS AND ISOLATED THUNDER ARE POSSIBLE FROM MIDDAY
WED THROUGH LATE WED AFTERNOON.

&&

.MARINE...

GUSTY SOUTHWEST WINDS WILL GRADUALLY DIMINISH AS LOW PRESSURE
MOVES ACROSS NORTHEAST WISCONSIN. A SMALL CRAFT ADVISORY IS NOW
IN EFFECT. THE SOUTHWEST WINDS WILL HELP TO PUSH THE FOG OFFSHORE
AND DIMINISH IT.

&&

.PREV DISCUSSION... /ISSUED 333 PM CDT TUE MAY 26 2015/

SHORT TERM...

TONIGHT AND WEDNESDAY... FORECAST CONFIDENCE MEDIUM.

RAIN AND ISOLATED THUNDERSTORMS WITH A LEADING MID LEVEL SHORTWAVE/
VORT MAX AND ASSOCIATED SURFACE WARM FRONT IS LIFTING OUT OF
SOUTHERN WI THIS AFTERNOON. WINDS ARE SHIFTING TO THE SSW IN THE
WAKE OF THIS RAIN.

THE MAIN SHORTWAVE TROUGH IS SWINGING UP INTO SOUTHWEST WISCONSIN
NOW AND LEADING TO BROKEN LINES OF SHOWERS AND THUNDERSTORMS ALONG
THE LEADING EDGE THIS AFTERNOON. THESE SHOWERS WILL SWING INTO
SOUTHERN WI DURING THE AFTERNOON AND DIMINISH DURING THE EVENING AS
DRIER AIR SPREADS IN. THE SHEAR IS DIMINISHING AND CAPE IS MINIMAL.
SPC REMOVED OUR FORECAST AREA FROM THE SLIGHT RISK FOR THE REST OF
THE DAY.

WINDS WILL SHIFT TO THE SOUTHWEST AND BECOME VERY GUSTY LATE THIS
AFTERNOON AS THIS VORT MAX PASSES ACROSS SOUTHERN WI. GUSTS TO 30
MPH ARE LIKELY UNTIL SUNSET... THEN GUSTS TO 20 TO 25 MPH ARE
EXPECTED UNTIL LATE EVENING. WINDS WILL GRADUALLY SHIFT WEST AND
DIMINISH AFTER MIDNIGHT.

ONE MORE UPPER LEVEL DISTURBANCE SWINGING THROUGH THE BASE OF THE
UPPER TROUGH WILL SLIDE THROUGH IOWA AND NORTHERN IL THIS EVENING
AND SOME SHOWERS AND MAYBE A RUMBLE OF THUNDER COULD CLIP SOUTHERN
WI THROUGH LATE EVENING.

WEDNESDAY... FORECAST CONFIDENCE MEDIUM.

THE UPPER TROUGH WILL VERY SLOWLY TRACK ACROSS WI THROUGH WEDNESDAY
AFTERNOON. SHOWERS WILL BE POSSIBLE IN OUR AREA WITH THE UPPER
TROUGH OVERHEAD. THUS... THERE ARE SMALL POPS FROM TONIGHT THROUGH
WED AFTERNOON. THE BEST CHANCE FOR ANY SHOWER DEVELOPMENT IS MIDDAY
WED DUE TO DIURNAL HEATING AND CONTINUED WEAK VORTICITY ADVECTION.
MID LEVEL LAPSE RATES CONTINUE TO BE VERY WEAK AND THE SHEAR WILL BE
WEAK... SO ANY THUNDERSTORMS THAT MAY DEVELOP WILL NOT BE SEVERE.

TEMPERATURES WILL BE MILD ONCE AGAIN WEDNESDAY WITH 925MB TEMPS
HOVERING AT 18 TO 20C. EXPECT HIGHS IN THE MID TO UPPER 70S ASSUMING
THERE ARE BREAKS IN THE CLOUDS.

WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.

RIDGING ALOFT WILL BUILD INTO THE REGION USHERING IN QUIET WEATHER.
WHILE SOME MID-LEVEL WAA DOES BUILD INTO THE REGION ON
THURSDAY...THE MID AND LOWER LEVELS OF THE ATMOSPHERE REALLY DRY OUT
IN THE WAKE OF UPPER TROUGH THAT WILL MOVE THROUGH DURING THE DAY
ON WEDNESDAY. THE WEAK MID-LEVEL WAA WILL ALLOW THE 925 MB TEMPS
TO REACH AROUND 20 C. THESE WARM TEMPS...ALONG WITH MOSTLY CLEAR
SKIES...SHOULD ALLOW HIGHS ON THURSDAY TO REACH INTO THE LOW 80S
AWAY FROM LAKE MICHIGAN.

LONG TERM...

FRIDAY...FORECAST CONFIDENCE MEDIUM.

THE END OF THIS WEEK PRESENTS A COMPLICATED FORECAST. THE GREAT
LAKES REGION WILL BE UNDER THE INFLUENCE OF TWO DISTINCT LOW
PRESSURE SYSTEMS. ALOFT...A BROAD TROUGH WILL APPROACH THE GREAT
LAKES FROM THE SW WHILE ANOTHER TROUGH OVER THE HUDSON BAY AND NE
CANADA DEEPENS. THE COMBINATION OF THE APPROACHING LOW FROM THE
SW AND INTENSIFYING JET STREAK TO THE NE SHOULD PROVIDE AMPLE
UPPER-LEVEL FORCING FOR ASCENT IN THIS PERIOD. IN THE LOWER
LEVELS...ONE LOW WILL TRACK EAST ACROSS THE SOUTHERN TIER OF
CANADA WHILE A SECOND LOW MOVES NE OUT OF THE GREAT PLAINS PASSING
THROUGH NW WI. THESE SYSTEMS WILL BRING CONSIDERABLE WAA AS WELL
AS LOW AND MID-LEVEL MOISTURE AS THEY APPROACH THE REGION.

THE WAA AND MOISTURE...ALONG WITH THE AFOREMENTIONED UPPER-LEVEL
SUPPORT...WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS. THE
SHOWERS AND STORMS WILL BEGIN EARLY FRIDAY MORNING IN THE WARM
SECTOR OF THE NORTHERN LOW AND CONTINUE AS THE NORTHERN LOW MOVES
OFF TO THE THE EAST DURING THE DAY ON FRIDAY. THE PRECIP WILL
STICK AROUND ON FRIDAY NIGHT AND EARLY SATURDAY MORNING AS THE
SOUTHERN LOW MOVES INTO THE REGION BEFORE HIGH PRESSURE FINALLY
BUILDS IN FROM SOUTH CENTRAL CANADA AND PUSHES ALL THE PRECIP OFF
TO THE EAST. FINALLY...CONSIDERABLE INSTABILITY...AROUND 1000 J/KG
MLCAPE AND 2000 J/KG MUCAPE...WILL BUILD IN ON FRIDAY AFTERNOON...SO
THUNDERSTORMS ARE LIKELY. HOWEVER... BULK SHEAR VECTORS APPEAR TO
BE WEAK IN THIS PERIOD...SO ANY SEVERE THREAT IS MINIMAL.

SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM

A FEW SHOWERS MAY LINGER ON SATURDAY MORNING BEFORE HIGH PRESSURE
BECOMES ENTRENCHED OVER THE REGION. UPPER LEVEL FLOW WILL REMAIN
LARGELY ZONAL THROUGH THE PERIOD AND THE MID LEVELS REMAIN
UNSATURATED. COOLER TEMPERATURES SHOULD PREVAIL...ESPECIALLY ON
SATURDAY AND SUNDAY...WITH 925 TEMPS A FULL 10 C COOLER THAN EARLIER
IN THE WEEK. THAT SHOULD TRANSLATE TO HIGH TEMPERATURES IN THE LOWER
60S. THE HIGH PRESSURE WILL REMAIN OVER THE STATE INTO EARLY NEXT
WEEK...KEEPING RAIN CHANCES OUT OF THE FORECAST AREA. THE AIR
MASS WILL GRADUALLY MODIFY...ALLOWING HIGH TEMPERATURES TO BUILD
UP TO THE LOW 70S ON MONDAY AND TUESDAY.

AVIATION/00Z TAFS/...

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... WITH GUSTS TO
30 KNOTS POSSIBLE. EXPECT SLIGHTLY REDUCED WIND GUSTS THIS EVENING
TO PERSIST UNTIL AROUND MIDNIGHT UNTIL THE WINDS SHIFT TO THE WEST.

A PERIOD OF MVFR CIGS ARE POSSIBLE FROM LATE TONIGHT THROUGH LATE
WEDNESDAY MORNING AS AN UPPER LEVEL TROUGH SLOWLY MOVES ACROSS THE
REGION. SCATTERED SHOWERS AND ISOLATED THUNDER ARE POSSIBLE FROM
MIDDAY WED THROUGH LATE WED AFTERNOON.

MARINE...

GUSTY SOUTHWEST WINDS DEVELOPING FROM SOUTH TO NORTH THROUGH IL AND
WI ARE EXPECTED TO REACH SMALL CRAFT ADVISORY LEVELS THROUGH LATE
EVENING. A SMALL CRAFT ADVISORY IS NOW IN EFFECT. THE SOUTHWEST
WINDS WILL HELP TO PUSH THE FOG OFFSHORE AND DIMINISH IT THROUGH THE
EVENING. THE DENSE FOG ADVISORY WILL BE CANCELLED IN AREAS FROM
SOUTH TO NORTH AS THE SOUTHWEST WINDS DEVELOP.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT WEDNESDAY FOR LMZ644>646.

     SMALL CRAFT ADVISORY UNTIL 10 AM CDT WEDNESDAY FOR LMZ643.

&&

$$

UPDATE...HENTZ
TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC
WEDNESDAY NIGHT THROUGH TUESDAY...BSH



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