SPC AC 221629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT TUE AUG 22 2006
VALID 221630Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE NRN
PLAINS...
...NRN PLAINS...
PRESSURE FALLS WILL CONTINUE ACROSS THE NRN PLAINS TODAY AS
SHORTWAVE TROUGHS TOP UPPER RIDGE AND SHIFT SEWD TOWARDS THE NRN MS
RIVER VALLEY TONIGHT. THIS WILL ALLOW A WARM FRONT TO BECOME BETTER
DEFINED FROM PORTIONS OF THE NRN MS RIVER VALLEY INTO THE UPPER MO
RIVER VALLEY TODAY...WITH A WEAK LOW CENTER LIKELY EVOLVING INTO
SWRN ND/NWRN SD/SERN MT. WARM SECTOR AIR MASS WILL BE MOISTENING
THROUGH THE DAY WITH LOWER TO MID 60F SURFACE DEW POINTS POSSIBLE
INTO SD BY THE LATE AFTERNOON. WITH STRONG SURFACE HEATING AND
INCREASING ASCENT AHEAD OF WEAK SHORTWAVE TROUGH AND ALONG NOSE OF
STRENGTHENING SSWLY LLJ...POTENTIAL FOR INITIATION WILL INCREASE
LATER TODAY NEAR THE SURFACE FRONT.
FORECAST SOUNDINGS INDICATE MLCAPE WILL EXCEED 2000 J/KG WITH
WEAKENING CINH BY 21Z ALONG AND JUST SOUTH OF SURFACE WARM FRONT
INTO N-CENTRAL SD/S-CENTRAL ND...WITH SUFFICIENT WNWLY FLOW ALOFT
FOR 35-45 KT EFFECTIVE SHEAR. APPEARS ANY DIURNAL DEVELOPMENT WILL
THEREFORE OCCUR WITHIN A FAVORABLE ENVIRONMENT FOR SURFACE-BASED
SUPERCELLS INTO THE EVENING. EXPECT OVERALL INCREASE/EVOLUTION INTO
A MCS ALONG NOSE OF STRENGTHENING LLJ THROUGH THE EVENING/OVERNIGHT
NORTH OF THE SURFACE FRONT INTO PORTIONS OF ERN ND/NERN SD WHICH
WILL SPREAD ESEWD INTO CENTRAL MN LATER TONIGHT. APPEARS THIS
ACTIVITY WILL REMAIN ELEVATED...THOUGH STEEP MID LEVEL LAPSE RATES
AND INFUSION OF 10-12C H85 DEW POINTS SHOULD SUSTAIN MODERATE
MUCAPE. STRONG EFFECTIVE SHEAR IN EXCESS OF 45 KT WILL ALSO FAVOR
ELEVATED SUPERCELLS AND ORGANIZED CLUSTERS/LINES...FURTHER
INCREASING THE POTENTIAL FOR LARGE HAIL. DAMAGING WIND THREAT LATER
TONIGHT WILL DEPEND ON DEGREE OF BOUNDARY LAYER
STABILIZATION...THOUGH ISOLATED DAMAGING WINDS MAY OCCUR.
..EVANS/TAYLOR.. 08/22/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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