Heat in Wisconsin, June 16 to 20, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
103 PM CDT SAT JUN 16 2012

.UPDATE...MAIN BAND OF SHOWERS/TSTORMS MOVING OUT OF THE CWA BUT
WILL STILL SEE ISOLD TO SCT SHOWERS/TSTORMS AS SHORTWAVE TROUGH
CONTINUES TO PROGRESS NEWD THROUGH SRN WI. OTHERWISE WILL WAIT FOR
NEXT UPPER WAVE CURRENTLY OVER ERN NE WITH CONVECTIVE DEVELOPMENT
ALONG A SFC TROUGH LINE FROM THE IA/MO BORDER THIS AFTERNOON NEWD
INTO SE WI FOR TNT. CHANCES FOR RAIN LESS CERTAIN OVER THE NRN
HALF OF THE CWA TNT AS AFOREMENTIONED UPPER WAVE AND CONVECTION
MAY STAY JUST TO THE SOUTH. A DRY WLY FLOW AND SUNSHINE THEN
EXPECTED FOR SUNDAY WITH SCT MID TO HIGH CLOUDS FOR THE AFTERNOON.

&&

.AVIATION/18Z TAFS/...TOWERING CUMULUS CLOUDS AROUND 3-4 KFT THIS
AFTERNOON WITH ISOLD TO SCT SHOWERS/STORMS. AREAS OF MVFR CIGS/VSBYS
WILL OCCUR AT TIMES ESPECIALLY WITH ANY RAIN. A MORE ORGANIZED
AREA OF SHOWERS/TSTORMS WILL AFFECT FAR SRN AND SE WI THIS EVENING
AND POSSIBLY LINGER INTO THE OVERNIGHT. MAINLY VFR CONDITIONS WILL
PREVAIL OUTSIDE THE RAIN AREA WITH IFR TO MVFR CONDITIONS WITH THE
STRONGER SHOWERS/TSTORMS. A DRY WLY FLOW AND SUNSHINE THEN
EXPECTED FOR SUNDAY WITH SCT MID TO HIGH CLOUDS FOR THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 330 AM CDT SAT JUN 16 2012/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

PERSISTENT MCV OVER EASTERN IOWA EARLY THIS MORNING IS FCST TO
LIFT INTO CENTRAL TO SOUTHERN WISCONSIN BY 18Z. CURRENT
SHOWER/THUNDERSTORM ACTIVITY WITH IT IS SCATTERED.
HOWEVER...NEARLY EVERY MODEL INCREASES THE ACTIVITY AS IT GETS
INTO OUR AREA COINCIDENT WITH DIURNAL HEATING AND INCREASING CAPE
VALUES. PRECIPITABLE WATER OF 1.9 AND 1.7 INCHES FROM THE GFS AND
NAM RESPECTIVELY AT KMSN...ARE LIKELY OVERDONE AND A SYMPTOM OF
THE MODELS HAVING A DIFFICULT TIME WITH THE BOUNDARY LAYER
MOISTURE. THESE VALUES ARE PUSHING 2 STANDARD DEVIATIONS ABOVE THE
CLIMATE NORM. HOWEVER...SFC DEWPOINTS CURRENTLY IN THE MID 40S TO
LOW 50S SHOULD PUSH OFF TO THE EAST AS MID 60 DPTS ARRIVE WITH AN
INCREASING SOUTHERLY FLOW THIS MORNING. HAVE INCREASED POPS TO
LIKELY ACROSS MOST OF THE AREA FOR TODAY. HAVE LOWERED HIGHS FOR
TODAY TO COMPENSATE FOR THE INCREASED CLOUD COVER AND EXPECTED
RAINFALL.

TIMING OF THIS FIRST WAVE OF PRECIP WITH THE MCV IS PRETTY
STRAIGHT FORWARD TODAY. TONIGHT IS ANOTHER MATTER. THE MAIN SFC
TROF/CDFNT OUT WEST WILL PUSH THROUGH LATE THIS EVENING AND AFTER
MIDNIGHT. THE EXITING LEAD MCV WILL LIKELY BRING A SUPPRESSION
INFLUENCE TO CONTINUED SHOWERS/STORMS ACROSS THE EAST LATE THIS
AFTERNOON AND EVENING. BUT CLEARING IN THE WEST AND THE APPROACH
OF THE FRONT SHOULD LEAD TO MORE SHOWERS/STORMS WEST OF MADISON
THIS EVENING. THE MAIN UPPER LEVEL SHORT WAVE WITH THE FRONT LIFTS
QUICKLY TO THE NORTHEAST. ADDITIONALLY...THE LOW LEVEL FLOW VEERS
WESTERLY AND WE LOSE SOME LOW LEVEL CONVERGENCE. SO...THERE IS
PLENTY OF UNCERTAINTY AS TO HOW MUCH CONVECTION WE/LL SEE WITH THE
TROF/CDFNT PASSAGE TONIGHT.

THE THREAT FOR ANY SEVERE WEATHER LOOKS LIMITED GIVEN THE AMOUNT
OF CLOUD COVER EXPECTED. IF THERE IS A FAVORED AREA...IT SHOULD BE
OUT WEST LATER THIS AFTERNOON AND EVENING WITH POTENTIAL CLEARING
RESULTING IN QUICK HEATING AHEAD OF THE APPROACHING FRONT.

SHORT TERM...SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS
MEDIUM.

A FEW SHOWERS OR STORMS MAY LINGER SUNDAY MORNING IN THE FAR
SOUTHEAST COUNTIES...AS THE FRONT MOVES OUT OF THE REGION.
OTHERWISE...A WEAK HIGH PRESSURE RIDGE WILL SHIFT THROUGH THE
REGION. NAM/GFS FORECAST SOUNDINGS SHOWING A DRY AIRMASS WITH THIS
FEATURE ACROSS THE AREA...WITH WEAK COLD AIR ADVECTION. THUS...A
NICE DAY IS EXPECTED FOR SUNDAY. HIGHS SHOULD REACH THE MID 80S
INLAND...TURNING COOLER NEAR THE LAKE WITH LAKE BREEZE IN
AFTERNOON.

WARM AIR ADVECTION THEN KICKS IN ACROSS THE AREA SUNDAY NIGHT INTO
MONDAY. SOUTHWESTERLY LOW LEVEL JET GRADUALLY INCREASES IN
MAGNITUDE DURING THIS TIME. THIS FEATURE IS STRONGEST AND POINTS
INTO LOCATIONS WEST AND NORTHWEST OF THE AREA SUNDAY NIGHT. LEFT
LOWER END POPS IN FORECAST FOR SUNDAY NIGHT ACROSS MAINLY SOUTH
CENTRAL WISCONSIN...AS AREA WILL BE ON FAR EASTERN PERIPHERY OF
POSSIBLE CONVECTION.

BETTER SHOT FOR SHOWERS AND STORMS COMES MONDAY...AS LOW LEVEL JET
INCREASES TO 40 TO 50 KNOTS...AND POINTS INTO CENTRAL WISCONSIN.
THIS FEATURE WILL COMBINE WITH INCREASING SOUTH TO SOUTHWEST WINDS
TO BRING INCREASING MOISTURE INTO THE AREA. SUBSEQUENT DEW POINTS
WILL RISE INTO THE MID 60S MONDAY.

LOW LEVEL JET NOSE SHOULD FOCUS MOST CONVECTION JUST NORTH OF THE
AREA...BUT NORTHERN COUNTIES WILL BE CLOSE ENOUGH TO KEEP CHANCE
POPS GOING. STRONG CAP WITHIN WARM SECTOR ACROSS MOST OF THE AREA
WILL BE LIMITING FACTOR FOR CONVECTION...SO TAPERED POPS TO SLIGHT
CHANCES TO THE SOUTH. PARTIAL SUNSHINE SHOULD ALLOW FOR VERY WARM
TEMPERATURES INTO THE 90 TO 94 DEGREE RANGE...WITH HEAT INDEX
VALUES WELL INTO THE 90S.

LEFT HIGHEST POPS IN NORTHWEST COUNTIES SUNDAY NIGHT...WITH
ANOTHER LOW LEVEL JET NOSE TRYING TO WORK INTO FAR SOUTHWEST
WISCONSIN. LOWERED POPS LATER IN THE NIGHT WITH DECREASING
INSTABILITY.

LONG TERM...TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS
MEDIUM.

GFS/ECMWF SHOWING HOT AND HUMID CONDITIONS CONTINUING
TUESDAY...WITH AREA IN WARM SECTOR AIRMASS. MODELS THEN DIFFER
WITH COLD FRONT MOVING SLOWLY SOUTHEAST THROUGH THE REGION THROUGH
THURSDAY...SO WENT WITH CONSENSUS POPS AND TEMPERATURES. COOLER
AIRMASS THEN ON TAP FOR FRIDAY...WITH CANADIAN HIGH BUILDING INTO
THE REGION.

AVIATION/12Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THE PERIOD...EXCEPT POSSIBLE BRIEF
MVFR EPISODES IN AND AROUND ANY THUNDERSTORMS.

SHOWERS/STORMS ARE EXPECTED TO SPREAD ACROSS THE AREA THIS
MORNING AS A MID LEVEL DISTURBANCE MOVES OVERHEAD. THIS FEATURE
WILL EXIT BY MID AFTERNOON WITH THE FOCUS THEN SHIFTING WEST OF
MADISON WITH THE APPROACH OF A SFC TROF/CDFNT. THAT FRONT SHOULD
PUSH THROUGH KMSN AROUND MIDNIGHT TONIGHT AND KMKE ABOUT 3 HOURS
LATER. THE CHANCE FOR SHOWERS/STORMS WILL CONTINUE WITH THE
FRONTAL PASSAGE.

&&

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

UPDATE...GEHRING
TODAY/TONIGHT AND AVIATION/MARINE...WOOD
SUNDAY THROUGH FRIDAY...DAVIS

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
956 AM CDT SAT JUN 16 2012

WIZ046-047-051-052-056>060-062>072-170900-
MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE-
WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE-
LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA-
956 AM CDT SAT JUN 16 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE LIKELY TODAY INTO TONIGHT AS THE COMBINATION OF AN
UPPER LEVEL DISTURBANCE MOVES THROUGH TODAY...FOLLOWED BY A COLD
FRONT MOVING THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORM CHANCES RETURN FOR SUNDAY NIGHT THROUGH FRIDAY OF
NEXT WEEK AS SEVERAL LOW PRESSURE SYSTEMS MOVE THROUGH THE
NORTHERN PLAINS AND SOUTHERN CANADA...BRINGING A WAVERING FRONTAL
BOUNDARY NEAR OR ACROSS WISCONSIN.

HEAT INDICES WILL REACH THE MID 90S BOTH MONDAY AND TUESDAY
AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

LMZ643>646-170900-
SHEBOYGAN TO PORT WASHINGTON WI-
PORT WASHINGTON TO NORTH POINT LIGHT WI-
NORTH POINT LIGHT TO WIND POINT WI-
WIND POINT WI TO WINTHROP HARBOR IL-
956 AM CDT SAT JUN 16 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE LIKELY TODAY INTO TONIGHT AS THE COMBINATION OF AN
UPPER LEVEL DISTURBANCE MOVES THROUGH TODAY...FOLLOWED BY A COLD
FRONT MOVING THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

BREEZY SOUTH TO SOUTHWEST WINDS WILL LIKELY DEVELOP FROM MONDAY
THROUGH WEDNESDAY AS SEVERAL LOW PRESSURE SYSTEMS MOVE FROM THE
GREAT PLAINS TO THE NORTHERN GREAT LAKES AND CANADA. A SMALL CRAFT
ADVISORY MAY BE NEEDED FOR THE NEARSHORE WATERS.

THE FRONTAL BOUNDARIES FROM THESE LOWS WILL BRING SLIGHT CHANCES OF
THUNDERSTORMS TO PORTIONS OF LAKE MICHIGAN FROM MONDAY THROUGH
FRIDAY.

DAVIS/GEHRING
WWW.WEATHER.GOV/MKX