DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 181950
SWODY1
SPC AC 181948

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0248 PM CDT MON JUN 18 2007

VALID 182000Z - 191200Z

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER GREAT LAKES TO
ERN KS...

..UPPER GREAT LAKES TO MID MS VALLEY...

COLD FRONT IS ADVANCING STEADILY EWD ACROSS WRN WI INTO CNTRL IA.
THIS PORTION OF THE FRONTAL ZONE HAS BECOME QUITE ACTIVE
CONVECTIVELY WITH A NEARLY SOLID LINE OF THUNDERSTORMS NOW
STRETCHING FROM THE WRN PORTIONS OF LAKE SUPERIOR...TO NEAR DSM.
STRONG FORCING ACTING ON AN UNCAPPED AIRMASS WILL UNDOUBTEDLY AID
SQUALL LINE AS IT MOVES DOWNSTREAM ACROSS MOST OF WI INTO NERN IA.
ONE COMPLICATING FACTOR AHEAD OF THIS ACTIVITY IS THE NWD
DEVELOPMENT OF CONVECTION IN ASSOCIATION WITH SRN MO UPPER LOW/VORT.
CONSIDERABLE CLOUDS AND PRECIPITATION WILL SOON OVERSPREAD MUCH OF
SERN WI OVERTURNING BUOYANCY IN PLACE. FOR THIS REASON IT APPEARS
THE SQUALL LINE WILL BE MOST ACTIVE ACROSS NWRN/CNTRL WI INTO CNTRL
IA. DAMAGING WINDS ARE THE PRIMARY SEVERE THREAT...ALTHOUGH HAIL
COULD ALSO BE NOTED WITH THE STRONGER UPDRAFTS.

..CNTRL/SRN PLAINS...

EXTREME INSTABILITY HAS DEVELOPED AHEAD OF COLD FRONT ALONG AN AXIS
FROM SWRN KS INTO NWRN TX WHERE MLCAPE VALUES NOW RANGE FROM
3000-4500 J/KG. DESPITE THE LOW LEVEL FOCUS FOR CONVECTIVE
DEVELOPMENT ACROSS THIS REGION WEAK SHORTWAVE RIDGING AND SUBSIDENCE
ALOFT WILL LIKELY PROVE DETRIMENTAL FOR THUNDERSTORM
DEVELOPMENT...ESPECIALLY GIVEN THE WARMING MID LEVEL TEMPERATURES
AND ABUNDANCE OF CLOUD COVER.

..CENTRAL GULF STATES...

AN EXPANSIVE AREA OF THUNDERSTORMS EVOLVED ALONG THE CNTRL GULF SEA
BREEZE AROUND 15Z THIS MORNING. CONVECTIVE MOMENTUM AND NWD
PROPAGATION HAS ALLOWED THIS ACTIVITY TO SPREAD NWD AT ROUGHLY 25-30
KT INTO ECNTRL LA/CNTRL MS. GUSTY WINDS AND PERHAPS SOME HAIL COULD
ACCOMPANY THESE STORMS AS THEY MOVE NWD INTO THE EARLY EVENING
HOURS.

.DARROW.. 06/18/2007

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