MESOSCALE DISCUSSION 2252
NWS STORM PREDICTION CENTER NORMAN OK
0643 PM CDT MON AUG 25 2003
AREAS AFFECTED...S-CENTRAL/SERN WI AND SWRN MI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL
VALID 252343Z - 260145Z
ADDITIONAL THUNDERSTORM DEVELOPMENT IS ANTICIPATED ACROSS SRN WI
DURING THE NEXT 1-3 HOURS...WITH STORM MOTIONS ESEWD AT 30-35KT
TAKING ACTIVITY INTO SWRN MI WITH TIME THIS EVENING. A SEVERE
THUNDERSTORM WATCH MAY BE REQUIRED FOR PORTIONS OF THE DISCUSSION
AREA.
AT 2320Z AN E-W ORIENTED FRONTAL BOUNDARY...ENHANCED BY MESOSCALE
OUTFLOW...EXTENDED ALONG THE FAR SRN COUNTIES OF WI. THIS BOUNDARY
SHOULD SAG SLOWLY SWD DURING THE NEXT FEW HOURS OWING TO CONTINUED
PRODUCTION OF RAIN COOLED AIR FROM PRECIPITATION BAND FROM VOK TO 40
S MTW.
VAD WIND PROFILE AT DVN INDICATES LOW-LEVEL /0-1KM/ SWLY FLOW AROUND
20 KT THAT WILL ENHANCE ISENTROPIC LIFT ALONG AND NORTH OF FRONTAL
POSITION IN SRN WI. IN ADDITION...CLOUD/PRECIP BAND ORIENTED FROM
THE CENTRAL PLAINS ENEWD INTO CENTRAL WI IS ASSOCIATED WITH PLUME OF
STEEP 700-500MB LAPSE RATES...AROUND 7.5 C/KM BASED ON MODEL
SOUNDINGS FROM THE 12Z ETA. NARROW CORRIDOR OF WARM ADVECTION SOUTH
OF CLOUD BAND AND NORTH OF FRONT/OUTFLOW BOUNDARY...COMBINED WITH
100MB MLCAPE VALUES AROUND 2000 J/KG SHOULD RESULT IN CONTINUED
ISOLATED/SCATTERED THUNDERSTORM DEVELOPMENT. STORMS DEVELOPING
ACROSS NERN IA OR SRN WI WOULD TRACK ESEWD INTO SWRN MI...WHERE
SUFFICIENT INSTABILITY EXISTS TO SUSTAIN T-STORMS AND SEVERE THREAT.
SUFFICIENT 0-6KM SHEAR /AROUND 40KTS/ EXISTS FOR AN ORGANIZED
/SUSTAINED THREAT OF SEVERE THUNDERSTORMS THROUGH THIS EVENING INTO
THE EARLY PART OF THE OVERNIGHT PERIOD. HAIL AND DAMAGING WINDS
SHOULD BE THE MAIN THREAT GIVEN NLY SURFACE WINDS AND SHALLOW COLD
ADVECTION IN THE FRONTAL ZONE ACROSS SRN WI.
..BANACOS.. 08/25/2003
ATTN...WFO...IWX...GRR...LOT...MKX...DVN...ARX...
43389041 43608962 43398803 43228638 42898488 41938449
41928638 42178794 42199011 42649032
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