[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 241635
SWODY1
SPC AC 241633

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1133 AM CDT THU AUG 24 2006

VALID 241630Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS OF SEVERE THUNDERSTORMS ACROSS
PORTIONS OF ERN SD...SRN MN AND EXTREME WRN WI...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
ACROSS THE NRN AND CENTRAL PLAINS  AND THE UPPER MS VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS IN DELMARVA...

...SYNOPSIS...
POTENT SHORTWAVE TROUGH MOVING INTO WRN ND WILL SHIFT EWD INTO NRN
MN TONIGHT. SURFACE LOW OVER WRN SD AND ASSOCIATED N-S COLD FRONT IS
FORECAST TO MOVE EWD INTO THE ERN DAKOTAS/CENTRAL NEB BY EARLY
EVENING..AND THEN INTO MN/WRN IA TONIGHT. SURFACE LOW MOVING SHOULD
MAINTAIN CURRENT POSITION OF WARM FRONT THROUGH THE AFTERNOON FROM
EAST CENTRAL SD ESEWD ACROSS FAR SRN MN TO NEAR THE IL/WI BORDER.
CONVERGENCE ALONG WARM FRONT SHOULD BE ENHANCED BY STRONG HEATING
SOUTH AND CLOUDS/COOLER TEMPERATURES NORTH OF THE BOUNDARY. OTHER
THUNDERSTORMS ARE ALSO POSSIBLE ALONG EWD EXTENSION OF FRONT FROM
THE UPPER MIDWEST INTO THE MID ATLANTIC STATES.

...NRN PLNS INTO UPR MS VLY...
WIDESPREAD DAMAGING WIND EVENT AND POSSIBLY STRONG TORNADOES ARE
POSSIBLE LATE THIS AFTERNOON AND TONIGHT...ESPECIALLY ACROSS THE
MODERATE RISK AREA. LARGE AREA OF CLOUDS ACROSS MOST OF THE DAKOTAS
WILL REDUCE THE AMOUNT OF HEATING ACROSS THIS AREA THIS AFTERNOON.
HOWEVER...STRONG FORCING HAS ALREADY RESULTED IN ELEVATED SEVERE
THUNDERSTORMS ACROSS WRN ND IN ASSOCIATION WITH LARGE SCALE FORCING.
DESPITE STABLE BOUNDARY...EFFECTIVE SHEAR NEAR 50 KT AND MUCAPES IN
EXCESS OF 3000 J/KG...AS OBSERVED ON BIS MORNING SOUNDING...WILL BE
FAVORABLE FOR SUPERCELLS TO MOVE/DEVELOP SEWD ALONG INSTABILITY AXIS
TOWARD SERN ND/NRN SD. DESPITE RELATIVELY STABLE BOUNDARY
LAYER...THE DEGREE OF SHEAR/INSTABILITY WILL BE FAVORABLE FOR SEVERE
HAIL/WINDS.

OTHER ELEVATED STORMS ARE ALSO LOCATED ACROSS SERN MN/WRN WI IN 
ASSOCIATION WITH WARM ADVECTION NORTH OF WARM FRONT. DEEP LAYER
SHEAR AND STRONG INSTABILITY ALSO FAVOR SEVERE HAIL/WINDS WITH THESE
STORMS AS THEY GRADUALLY MOVE/DEVELOP SEWD.

SURFACE BASED STORMS ARE MOST LIKELY TO DEVELOP NEAR THE WARM FRONT
ACROSS ERN SD/SWRN MN WHERE STRONG HEATING SHOULD RESULT IN AN
EXTREMELY UNSTABLE AIR MASS WITH MLCAPES IN EXCESS OF 4000 J/KG.
WARM 700 MB TEMPERATURES BETWEEN 14-16C SHOULD KEEP THIS AREA CAPPED
MOST OF THE DAY...THOUGH THIS LAYER WILL COOL AS LARGE SCALE FORCING
SPREADS INTO THE REGION. THE POTENTIAL EXISTS FOR STORMS TO FIRST
DEVELOP N OF THE BOUNDARY AS THE CAP SHOULD ERODE MORE RAPIDLY NORTH
OF THE BOUNDARY. THOUGH THESE STORMS WOULD BE SLIGHTLY
ELEVATED...THE STORMS MAY QUICKLY EVOLVE INTO A 
LINE/BOW AND THEN MOVE ESEWD. WIDESPREAD WIND DAMAGE WOULD BE
POSSIBLE GIVEN THE DEGREE OF INSTABILITY AND DEEP LAYER SHEAR.
EVENTUALLY...SURFACE BASED STORMS ARE EXPECTED TO DEVELOP NEAR THE
WARM FRONT LATE THIS AFTERNOON. THE EXTREME INSTABILITY AND 60 KT
DEEP LAYER SHEAR WILL RESULT IN THE RAPID DEVELOPMENT OF SUPERCELLS.
ANY DISCRETE SUPERCELLS THAT CAN BE MAINTAINED NEAR THE WARM FRONT
WILL INGEST A MOIST BOUNDARY LAYER WITH 25-30 KT 1 KM SHEAR...WHICH
WOULD BE SUPPORTIVE OF STRONG TORNADOES LATE THIS AFTERNOON/EVENING.
AS THE LOW LEVEL JET STRENGTHENS THIS EVENING ...THE SUPERCELLS
SHOULD EVOLVE INTO A LINE/BOW AND MOVE ESEWD ALONG WARM FRONT ACROSS
SRN MN AND INTO WI...WITH THE MAIN THREAT BECOMING DAMAGING WIND
GUSTS...WITH SOME POSSIBLY EXTREME.

...NEB...
HIGH BASED THUNDERSTORMS ARE ALSO POSSIBLE ALONG SRN EXTENSION OF
COLD FRONT FROM SERN SD SWWD ACROSS NEB LATE THIS AFTERNOON. DEEP
LAYER SHEAR AROUND 30 KT AND DEWPOINT DEPRESSIONS NEAR 50F WOULD
SUPPORT STRONG WIND GUSTS.

...DELMARVA...
ABUNDANT SUNSHINE WAS PREVALENT ACROSS THE REGION AND SHOULD RESULT
IN AT LEAST MODERATE INSTABILITY THIS AFTERNOON. GIVEN WEAK FRONTAL
BOUNDARY AND WEAK IMPULSES MOVING EWD THROUGH THE AREA...A FEW
STRONG STORMS WITH MARGINALLY SEVERE WIND GUSTS ARE POSSIBLE THIS
AFTERNOON.

..IMY/TAYLOR.. 08/24/2006