SPC AC 131557
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1057 AM CDT SUN AUG 13 2006
VALID 131630Z - 141200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM KS/ERN NEB ACROSS IA INTO
SRN MN/SWRN WI...
...KS/ERN NEB ACROSS IA INTO SRN MN/SWRN WI...
A RATHER VIGOROUS S/WV TROUGH WILL BE CROSSING THE NRN PLAINS THIS
AFTERNOON...REACHING THE UPPER GREAT LAKES BY 12Z MON. SWLY FLOW
AHEAD OF TROUGH CONTINUES TO DIRECT MONSOONAL PLUME OF MOIST AIR
NEWD ACROSS PLAINS INTO UPPER MS VALLEY.
COLD FRONT CURRENTLY MOVING EWD EXTENDS FROM CENTRAL DAKOTAS/NEB
INTO NERN CO. A SURFACE TROUGH PRECEDES THE FRONT ACROSS WRN KS TO
NERN NM
WITH WARM AND ONLY MODESTLY STEEP MID LEVEL LAPSE RATES IN ADVANCE
OF THE COLD FRONT THAT IS MOVING EWD ACROSS CENTRAL DAKOTAS/NEB
TODAY...SEVERE THUNDERSTORMS WILL REQUIRE STRONG SURFACE HEATING FOR
INITIATION.
BASED ON CURRENT TEMP AND CLOUD COVER TRENDS...HEATING WILL BE
SUFFICIENT FOR DEVELOPMENT OF SURFACE BASED THUNDERSTORMS AHEAD OF
COLD FRONT AND THE SURFACE TROUGH BY MID AFTERNOON. ADDITIONALLY
SURFACE TEMPERATURES WILL LIKELY REACH LOW 90S INTO SRN IA WHERE A
MORE FAVORABLE SHEAR ENVIRONMENT WILL BE IN PLACE. MLCAPES AOA 2000
J/KG FROM SRN IA SWWD INTO KS WILL SUPPORT DEVELOPMENT OF
STRONG/SEVERE THUNDERSTORMS BY MID AFTERNOON.
GENERALLY SHEAR OF 20KT OR LESS IN KS WILL FAVOR PULSE/MULTICELLULAR
ACTIVITY WITH DOWNBURSTS AND A MARGINALLY SEVERE HAIL THREAT.
FURTHER NE ACROSS IA...SHEAR OF 30-40KT WILL CONDITIONALLY SUPPORT
SUPERCELLS...PROVIDED SUFFICIENT HEATING/INSTABILITY DEVELOPS.
MODELS INDICATE A GOOD MCS SIGNAL BY LATER THIS AFTERNOON/EVENING
ACROSS NRN/CENTRAL IA WHICH WOULD LEAD TO A GREATER WIND DAMAGE
POTENTIAL. AGAIN AMOUNT OF SURFACE HEATING WILL BE THE CAVEAT AS TO
AMOUNT OF SEVERE POTENTIAL AS THE STRONG UVVS WITH THE S/WV TROUGH
PASS FURTHER N ACROSS MN INTO UPPER GREAT LAKES WHERE THERMODYNAMICS
ARE VERY LIMITED.
..HALES/JEWELL.. 08/13/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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