Severe Thunderstorm Warning 100, NWS Green Bay, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
315 PM CDT MON AUG 12 2002

PCPN COVERAGE AND POTENT OF SVR WX THE MAIN CHALLENGE TNT.

WITH SFC LOW WELL NORTH OF THE US/CAN BORDER...CDFNT MAKING MORE OF
ADVANCE INTO NW/NC WI THIS AFTN.  SFC TROF POSITION MOVING INTO NC WI
WITH NOTED WINDS TO MORE OF A SW DIRECTION OVER NC WI.  MEANWHILE 70
DPTS OVER MUCH OF C/EC WI AHD OF THE TROF/FRONT AND RECENT SAT IMAGES
INDICATE MARGINAL BREAKS IN THE CLD COVER...BUT MSAS INSTAB GRAPHICS
INDICATE -4 TO -6 LI. ISOLD SHRA/TSRA/S WERE DEVELOPG IN AVBL BREAKS
AHEAD OF SFC TROF AT 19Z.  CONVECTION MAY ALSO HAVE BEEN AIDED BY A WK
VORT CENTERED OVR NC WI AT 18Z.  AFT THIS ROUND OF CONVECTION...FRONT TO
THE WEST OVERALL QUIET EXCEPT NEAR AREA OF COUPLED JET OVER WRN IA.
EXPECT SOME OF THIS CONVECTION WILL WORK INTO AT LEAST THE SRN PORTION
OF THE CWA FOR OVERNIGHT AS FRONT SLIDES OVER.  WK CONVERGENCE AND
TIMING OF UPR JET PROVIDE LESS CHC OF TSRA FOR NRN WI OVERNIGHT

LATEST MODEL TRENDS IS TO SLOW DOWN THE FRONT FOR TUESDAY AS FRONTAL
BOUNDARY STILL LINGERS OVER SOUTEAST WI.  CLDS AND SCT SHRAS WILL STILL
HANG AROUND TUE OVER EC WI AS MOISTURE LINGERS.  AVN EVEN LIFTS A SFC
LOW ALONG THE BOUNDARY ON TUESDAY.  UPR TROF LAGS BEHIND FOR TUESDAY AS
WELL BUT MID LEVEL DRYING SHOULD BE SUFFICIENT TO EVENTUALLY END PCPN
OVER MOST LOCATIONS.

MDM RANGE MODELS INDICATE A FAIRLY ACTIVE FLOW TWD THE WEEKEND AS NEAR
ZONAL FLOW REMAINS OVER THE UPPER MIDWEST.  REGION WILL BE IN A
TRANSISTION OR SERIES OF SFC LOWS WITH FRONTAL BOUNDARIES.

.GRB...NONE.

HELMAN
WWW.CRH.NOAA.GOV/GRB

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-122030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREEN BAY WI
1200 PM CDT MON AUG 12 2002

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF CENTRAL...NORTH CENTRAL
AND NORTHEAST WISCONSIN.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE ENTIRE
FORECAST AREA THIS AFTERNOON AND TONIGHT.

A COLD FRONT EXTENDING FROM NORTHEAST MINNESOTA TO NORTHWEST IOWA EARLY
TODAY...WILL MOVE INTO NORTHWESTERN WISCONSIN DURING THE AFTERNOON.  THE
FRONT WILL THEN TRACK OVER THE FORECAST AREA TONIGHT.  THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT THIS AFTERNOON AND
TONIGHT.  SINCE THE AIR MASS REMAINS MOIST AHEAD OF THE FRONT...THEIR IS
THE POTENTIAL OF THE ENVIRONMENT TO BECOME VERY UNSTABLE PRIOR TO THE
FRONT.  HOWEVER THE AMOUNT OF INSTABILITY WILL BE VERY DEPENDENT ON THE
AMOUNT OF SUNSHINE THIS AFTERNOON.  LATEST SATELLITE IMAGERY INDICATES
MOSTLY CLOUDY SKIES OVER THE REGION AROUND NOON.  IF SIGNIFICANT BREAKS
IN THE CLOUD COVER DOES OCCUR THIS AFTERNOON...A FEW STORMS MAY BECOME
SEVERE...ESPECIALLY DURING THE LATE AFTERNOON AND EVENING HOURS.
DAMAGING WINDS...AND TORRENTIAL RAINFALL WILL BE THE PRIMARY THREATS...
WITH LARGE HAIL ALSO POSSIBLE.

SOUTHWEST MARATHON COUNTY RECEIVED UP TO 5 INCHES OF RAIN LAST NIGHT...
CAUSING SOME RIVERS TO GO ABOVE THEIR BANKS.  ANY ADDITIONAL HEAVY
RAINFALL COULD CAUSE SOME SIGNIFICANT FLOODING THERE.

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

HELMAN
WWW.CRH.NOAA.GOV/GRB