SPC AC 151629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT WED JUL 15 2009
VALID 151630Z - 161200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
FROM THE SRN PLAINS TO THE TN VALLEY...
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR THE
HIGH PLAINS OF SE CO AND NE NM...
...SRN PLAINS TO TN VALLEY THIS AFTERNOON THROUGH TONIGHT...
THE PRIMARY NRN STREAM SHORTWAVE TROUGH CONTINUES TO PROGRESS EWD
OVER THE GREAT LAKES WHILE AN ASSOCIATED COLD FRONT MOVES EWD FROM
MO/IA/WI AS OF LATE MORNING TO IL/INDIANA/MI BY TONIGHT. THE WRN
EXTENT OF THIS FRONT IS DRIFTING SWD ACROSS SRN KS/NRN OK.
MEANWHILE...SEVERAL OVERNIGHT THUNDERSTORMS CLUSTERS AND REMNANT
MCV/S PERSIST AS OF LATE MORNING...ONE OF WHICH IS MOVING SEWD INTO
CENTRAL KY...AND ANOTHER IS MOVING EWD FROM ERN KS INTO WRN MO.
STRONG SURFACE HEATING AND AN INFLUX OF 70-75 F BOUNDARY LAYER
DEWPOINTS WILL CONTRIBUTE TO AFTERNOON MLCAPE VALUES IN THE
1500-3000 J/KG RANGE ALONG THE SRN/SWRN FRINGES OF THE ONGOING
CONVECTION...AND ADDITIONAL THUNDERSTORM DEVELOPMENT WILL BE
POSSIBLE THIS AFTERNOON ALONG THE RESIDUAL CONVECTIVE OUTFLOWS. THE
COMBINATION OF MODERATE-STRONG INSTABILITY AND MARGINAL DEEP LAYER
SHEAR ON THE SRN FRINGE OF THE WESTERLIES WILL SUPPORT A FEW
MULTICELL CLUSTERS CAPABLE OF PRODUCING A FEW DAMAGING GUSTS AND
LARGE HAIL.
OVERNIGHT...A 20-30 KT LLJ WILL AGAIN DEVELOP OVER THE SRN PLAINS
AND RESULT IN STRENGTHENING LOW-LEVEL WAA ON THE IMMEDIATE COOL SIDE
OF THE STALLED FRONT NEAR THE KS/OK BORDER. THIS SHOULD SUPPORT THE
FORMATION OF ANOTHER CLUSTER OF STORMS ALONG THE BOUNDARY
OVERNIGHT...WITH AN ATTENDANT THREAT FOR AT LEAST ISOLATED DAMAGING
WINDS/HAIL FROM SRN KS/NRN OK EWD INTO SW MO/NW AR.
...HIGH PLAINS OF CO/NM THIS AFTERNOON/EVENING...
LOW-LEVEL UPSLOPE FLOW WITH BOUNDARY LAYER DEWPOINTS IN THE MID 50S
AND STRONG SURFACE HEATING WILL SUPPORT THE DEVELOPMENT OF A FEW
THUNDERSTORMS THIS AFTERNOON IN PROXIMITY TO THE RATON MESA...AND
STORMS WILL SPREAD EWD OVER THE HIGH PLAINS DURING THE EVENING.
VERTICAL SHEAR AND INSTABILITY WILL BE MARGINALLY SUFFICIENT FOR
ORGANIZED MULTICELL CLUSTERS...AND PERHAPS SOME BRIEF SUPERCELL
STRUCTURES...ALONG WITH THE POTENTIAL FOR AT LEAST ISOLATED LARGE
HAIL/DAMAGING WINDS THROUGH LATE EVENING.
...IL/INDIANA/LOWER MI THROUGH EARLY TONIGHT...
SOME DESTABILIZATION IS EXPECTED THIS AFTERNOON IN ADVANCE OF THE
COLD FRONT AND TO THE N OF THE ONGOING CLOUDS/CONVECTION FARTHER S
ACROSS SRN IL/INDIANA/KY. HOWEVER...MID LEVEL LAPSE RATES ARE
RATHER POOR OVER THIS AREA...AND THE MAGNITUDE OF INSTABILITY SHOULD
REMAIN SOMEWHAT MARGINAL THROUGH THE AFTERNOON /MLCAPE OF 500-1000
J/KG/. GIVEN ONLY ISOLATED THUNDERSTORM DEVELOPMENT EXPECTED ALONG
THE FRONT...ALONG WITH RATHER MODEST INSTABILITY AND UNIDIRECTIONAL
WIND PROFILES...THE SEVERE THREAT APPEARS TO BE LIMITED TO ONLY
ISOLATED STRONG WIND GUSTS AND MARGINALLY SEVERE HAIL THIS
AFTERNOON/EVENING.
..THOMPSON/COOK/GARNER.. 07/15/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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