Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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110
FXUS63 KMKX 241642 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1142 AM CDT SUN APR 24 2016

.UPDATE...

HIGH BASED SHOWERS APPARENT ON RADAR ARE REACHING THE GROUND AS
SPRINKLES OR BRIEF LIGHT SHOWERS ALONG AND NORTH OF I-94 THIS
MORNING DUE TO LOW LEVEL DRY AIR. THESE ARE ASSOCIATED WITH 850-
700MB WARM AIR ADVECTION... FRONTOGENESIS AND WEAK SHORTWAVE ENERGY.
THE 12Z MODELS ARE ALL SHOWING THE SLOPED 925-850-700MB BAROCLINIC
ZONE WITH DECENT OMEGA VALUES STALLING OVER CENTRAL/SOUTHERN WI
TODAY ALONG AND NORTH OF A SURFACE/925MB FRONT THAT EXTENDS ROUGHLY
FROM THE DELLS TO WAUKESHA TO JUST WEST OF KENOSHA. THE FRONT IS
STALLING ITS NORTHEASTWARD PROGRESSION THANKS TO THE COLD FEED OFF
OF LAKE MICHIGAN. LIGHT SHOWERS AND MID LEVEL CLOUDS WILL BE
POSSIBLE ALONG AND NORTH OF THIS FRONT ALL DAY.

KEPT MENTION OF THUNDER POSSIBILITY FOR THE AFTERNOON DUE TO A MID
LEVEL SHORTWAVE IN THE VICINITY. THIS WILL ALLOW FOR STEEPER MID
LEVEL LAPSE RATES AND WEAK INSTABILITY. JUST A FEW RUMBLES OF
THUNDER POSSIBLE... NO STRONG THUNDERSTORMS.

MEANWHILE... A LARGE CIRRUS SHIELD ASSOCIATED WITH WEAKENING SHOWERS
IN WESTERN IOWA IS SPREADING INTO SOUTHERN WI LATE THIS MORNING.
ASIDE FROM SOME FILTERED SUNSHINE... IT IS LOOKING LIKE A MUCH
CLOUDIER DAY THAN PREVIOUSLY FORECAST. AS FOR TEMPERATURES...I AM
HESITANT TO PULL BACK ON THE INLAND TEMPS SOUTH OF THAT FRONT. 925MB
TEMPS ARE FORECAST TO REACH 19C SOUTHWEST OF MADISON TODAY WHICH
WOULD YIELD MAX TEMPS IN THE MID 70S AT LEAST... DESPITE THE CLOUDY
SKIES. WE DID LOWER MAX TEMPS NORTHEAST OF THE FRONT TO ACCOUNT FOR
MORE CLOUDS AND PRECIP TODAY.

&&

.AVIATION/18Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THIS EVENING. CHANCE OF LIGHT
RAIN/SPRINKLES TODAY AND THIS EVENING ROUGHLY NORTH OF LINE FROM
DELLS TO WAUKESHA.

SOUTHWESTERLY WINDS OF 25 TO 35 KT BETWEEN 1000 AND 2000 FEET WILL
CREATE MARGINAL CONDITIONS FOR WIND SHEAR ONCE AGAIN LATE THIS
EVENING INTO THE EARLY MORNING HOURS.

MVFR CIGS/FOG WILL BE POSSIBLE NORTH OF MADISON AND MILWAUKEE...
MORE TOWARD SHEBOYGAN AND CENTRAL WI... LATE TONIGHT ALONG A STALLED
WARM FRONT. THIS FRONT WILL BE THE FOCUS FOR POSSIBLE SHOWERS AND
THUNDERSTORMS MONDAY. ANOTHER FRONT COULD BRING THUNDERSTORMS TO THE
REST OF SOUTHERN WI LATE MONDAY AFTERNOON/EVENING.

&&

.MARINE...

LOOK FOR SOUTHEAST WINDS TODAY 8 TO 12KTS...WITH A FEW GUSTS
APPROACHING 17KTS AT TIMES.  WINDS WILL BACK TO EASTERLY
TONIGHT...THEN VEER BACK TO THE SOUTHEAST TO SOUTH ON MONDAY AHEAD
OF AN APPROACHING LOW PRESSURE SYSTEM.  ONCE THE LOW PASSES
BY...STRONGER NORTHEAST WINDS WILL PUSH DOWN THE LAKE LATE MONDAY
NIGHT INTO TUESDAY. THIS COULD RESULT IN SMALL CRAFT ADVISORY
CONDITIONS...ESPECIALLY NORTH OF MILWAUKEE. WINDS AND WAVES WILL
DECREASE BY TUESDAY NIGHT AS HIGH PRESSURE WITH AN EASTERLY FLOW
SETTLE ACROSS THE REGION.

&&

.PREV DISCUSSION... /ISSUED 431 AM CDT SUN APR 24 2016/

TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.

A SURGE OF 850-700 MB WARM ADVECTION HAS RESULTED IN A CLUSTER OF
HIGH BASED LGT SHOWERS OVER NE IA AND SW WI. BELIEVE THIS AREA WILL
CONTINUE INTO SOUTH CENTRAL WI THIS MORNING AS THE WARM ADVECTION
AND APPROACHING UPPER RIDGE AXIS SHIFTS EWD. WILL KEEP CHANCES LOW
HOWEVER GIVEN THE COOL AND FAIRLY DRY LOW LEVELS. THE OTHER
CHALLENGE IS THE NWD MOVEMENT OF THE WARM FRONT INTO SRN WI AS THE
STRONG SFC LOW OVER SD WILL SLOWLY TRACK TO SRN MN BY 12Z MON. THE
ONSHORE FLOW MAKES THE TEMP FCST IN ERN WI DIFFICULT. GIVEN THE COOL
TEMPS AND ELY FLOW THIS MORNING...DID COOL TEMPS IN THE EAST TODAY
FROM THE PRIOR FCST BUT STILL 70S OVER SOUTH CENTRAL WI.

THE WARM FRONT WILL THEN MOVE TO C WI TNT WITH MILD AND RELATIVELY
HUMID CONDITIONS. CHANCES OF SHOWERS AND SLIGHT CHANCES OF TSTORMS
ARE FORECAST BUT MESO MODELS SHOW A WEAKENING AREA OF SHOWERS TO
MOVE INTO SW WI DURING THE EARLY MORNING HOURS AND CONTINUE TO
WEAKEN AS IT MOVES ACROSS SRN WI. THIS SEEMS PLAUSIBLE GIVEN THE
MAIN VORT MAX THAT IS ROTATING AROUND THE UPPER LOW TRACKS FROM THE
C PLAINS INTO SRN MN...VERSUS FARTHER TO THE EAST.

MONDAY...FORECAST CONFIDENCE...MEDIUM

WILL LIKELY SEE SHOWERS AND A FEW STORMS IN THE MORNING AS A WEAK
WAVES PUSHES THROUGH...WITH A BRIEF BREAK IN PRECIP THEN POSSIBLE
INTO EARLY AFTERNOON. SHOULD SEE MORE SHOWERS AND STORMS DEVELOP
IN THE AFTERNOON AND INTO EVENING AS LOW PRESSURE AND THE
ASSOCIATED COLD FRONT MOVE THROUGH. COULD SEE A FEW STRONG TO
SEVERE STORMS DEPENDING ON THE AMOUNT OF HEATING/INSTABILITY AND
TIMING OF THE FRONT. SEEING DECENT SHEAR IN MODELS...WITH 0-6 KM
VALUES AROUND 35-45 KT. SPC HAS A MARGINAL RISK FOR SEVERE STORMS
ACROSS THE SOUTHERN TWO-THIRDS OF THE FORECAST AREA.

THE OTHER ISSUE MONDAY WILL BE TEMPS. OVERALL...LATEST MODELS
HAVE TRENDED NORTHWARD WITH THE WARM FRONT...RESULTING IN A HIGHER
PROBABILITY OF WARMER TEMPS. STILL A TRICKY SITUATION THOUGH...AS
A FARTHER SOUTH COLD FRONT WILL RESULT IN MUCH COOLER TEMPS.
TEMPERATURES NEAR THE LAKE ARE PROBLEMATIC AS WELL WITH WINDS
FORECAST TO BE GENERALLY ALONG SHORE. A FARTHER NORTH FRONT WILL
RESULT IN A WESTERLY COMPONENT AND MILDER TEMPS...WHILE A FARTHER
SOUTH FRONT WILL BRING IN AN EASTERLY COMPONENT AND KEEP THINGS
MUCH COOLER. GENERALLY WENT WITH A CONSENSUS BLEND OF THE FRONTAL
POSITION AND RESULTANT TEMPS.

TUESDAY THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM

LOOKS LIKE A COOLER PATTERN MID TO LATE WEEK WITH TEMPS BELOW
NORMAL FOR LATE APRIL. WITH ONSHORE WINDS FORECAST EVERY DAY...IT
WILL BE PARTICULARLY COOL NEAR LAKE MICHIGAN.

LOW PRESSURE WILL SLIDE BY TO THE SOUTH WEDNESDAY INTO
THURSDAY...WITH RAINFALL LIKELY ACROSS SOUTHERN WISCONSIN AS
FRONTOGENESIS SETS UP WITHIN THE BAROCLINIC ZONE. LOOKS LIKE A
SIMILAR SETUP AGAIN ON SATURDAY.

AVIATION/12Z TAFS...VFR CONDITIONS ARE EXPECTED TODAY AND TNT BUT
BROKEN CLOUD COVER AROUND 5-7 KFT WILL OCCUR AT TIMES ALONG WITH
CHANCES OF SHOWERS AND PERHAPS OF TSTORM LATE TNT.

MARINE...SELY WINDS AND 1-3 FOOT WAVES WILL PREVAIL UNTIL MON
NT WHEN A COLD FRONT SWEEPS SOUTH. BRISK NLY WINDS AND HIGH WAVES
WILL DEVELOP AND CONTINUE INTO TUE. A SMALL CRAFT ADVISORY IS
LIKELY FOR THIS PERIOD.

&&

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

$$

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



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