SWODY1
SPC AC 251630
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT FRI JUN 25 2010
VALID 251630Z - 261200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS CENTRAL AND SOUTHERN
MINNESOTA...EXTREME NORTHERN IOWA AND SOUTHWESTERN WISCONSIN...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
FROM PARTS THE DAKOTAS EWD INTO WI...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER TN VALLEY EWD
INTO THE CAROLINAS...
...ERN DAKOTAS ACROSS MN TO NRN IA AND WI...
LEADING SHORTWAVE TROUGH...EMBEDDED WITHIN A BAND OF FASTER WLY MID
LEVEL FLOW...WAS MOVING EWD THROUGH MN/ERN SD THIS MORNING...WHILE
ANOTHER SHORT WAVE TROUGH WAS LOCATED IN MT. CONSIDERABLE CLOUDS AND
SCATTERED CONVECTION/PCPN STRETCHED FROM THE MN ARROWHEAD/NWRN WI
SWWD BACK TO NEAR THE ERN SD/ND BORDER. IN THE WAKE OF THIS LEAD
SHORTWAVE TROUGH...CONVECTION IS EXPECTED TO REMAIN WEAK OR ELEVATED
DUE TO WEAK SHORTWAVE RIDGING/ STRENGTHENING CAPPING INVERSION.
HOWEVER...DEEP LAYER SHEAR IN CLOUD BEARING LAYER AND MUCAPES AROUND
1500 J/KG MAY SUPPORT A FEW ELEVATED STORMS WITH MARGINALLY SEVERE
HAIL INTO THE AFTERNOON HOURS.
AS UPPER WAVE AND LARGE SCALE ASCENT APPROACHES FROM THE WEST THIS
AFTERNOON...MODELS ARE FAIRLY CONSISTENT ON STORMS DEVELOPING NEAR
REMNANT OUTFLOW BOUNDARY...WHICH IS EXPECTED TO REMAIN
QUASI-STATIONARY FROM NRN SD EWD INTO CENTRAL MN. ALSO...A WEAK
SURFACE LOW WAS LOCATED IN WRN SD AND SHOULD DRIFT EWD ALONG THE
BOUNDARY INTO ERN SD. THE ENHANCED CONVERGENCE ALONG BOUNDARY
...ESPECIALLY AHEAD OF SURFACE LOW...AND DIURNAL DESTABILIZATION OF
MOIST BOUNDARY LAYER FAVORS SURFACE BASED STORMS FORMING BY MID/LATE
AFTERNOON. GIVEN THE COMBINATION OF STRONG INSTABILITY AND 50 KT
BULK SHEAR...SUPERCELLS WITH VERY LARGE HAIL AND HIGH WINDS ARE
LIKELY SHORTLY AFTER INITIATION. ALSO...THE MOISTENING BOUNDARY
LAYER AND STRONGER LOW LEVEL SHEAR ALONG BOUNDARY MAY YIELD A
TORNADO OR TWO...GENERALLY IN THE WRN PORTION OF THE MDT RISK AREA.
A FEW HOURS AFTER STORMS DEVELOP...STRONG OUTFLOWS FROM STORMS ARE
EXPECTED TO EVOLVE INTO AN MCS. ALTHOUGH THE MEAN FLOW WOULD SUPPORT
A MORE EWD MOTION OF MCS...COMBINATION OF STRENGTHENING LOW LEVEL
JET FROM SRN NEB NEWD INTO SERN MN/WRN WI AND VERY STRONG
INSTABILITY AXIS OVER ERN SD/NEB WOULD SUPPORT THE SYSTEM MOVING
MORE SEWD THAN EWD. THEREFORE THE MODERATE RISK AND THREAT FOR
DAMAGING WINDS...WITH SOME CONVECTIVE GUSTS POSSIBLY A0A 80
MPH...HAS BEEN SHIFTED SEWD ON THE ERN END.
...CAROLINAS WWD ACROSS THE TN VALLEY TO THE SRN PLAINS...
WEAK FRONTAL BOUNDARY STRETCHED FROM THE ERN CAROLINAS WWD INTO NRN
AL/MS. STRONG HEATING...TEMPERATURES WARMING INTO THE MID 90S ACROSS
MOST OF THE AREA...OF THE VERY MOIST BOUNDARY LAYER... DEWPOINTS IN
THE MID 70S...SHOULD CONTRIBUTE TO NUMEROUS STORMS THIS AFTERNOON. A
BAND OF WNWLY 15-20KT FLOW ALOFT...COUPLED WITH VARIOUS SUBTLE
BOUNDARIES...MAY CONTRIBUTE TO SOME STORM ORGANIZATION. BRIEF AND
SPORADIC WIND DAMAGE SHOULD BE THE MAIN THREAT.
ELSEWHERE...WEAK VERTICAL SHEAR BUT STRONG INSTABILITY WILL SUPPORT
ISOLD/RANDOM WET MICROBURSTS DURING THE AFTERNOON.
...INTERIOR NORTHWEST/NRN ROCKIES...
ALL MODELS ARE CONSISTENT IN FORECASTING THUNDERSTORMS INCREASING IN
A SW-NE ORIENTED SWATH FROM NRN CA NEWD INTO WRN MT. WHILE
INSTABILITY IS NOT FORECAST TO BE PARTICULARLY STRONG...MLCAPES AOB
1000 J/KG AND A WEAK FRONTAL ZONE MAY SUPPORT A FEW PERSISTENT
STORMS WITH MARGINAL HAIL AND WIND POTENTIAL.
...FOUR CORNERS REGION...
DIURNAL HEATING COUPLED WITH MID LEVEL VORTICITY CENTER LOCATED ON
WRN FLANK OF SUBTROPICAL RIDGE OVER ERN AZ...WILL LIKELY AID IN HIGH
BASED AFTERNOON TSTMS. GIVEN 20-30 KT MID LEVEL SLY WINDS WITHIN
DEEPLY MIXED/DRY BOUNDARY LAYER...A POTENTIAL EXISTS FOR
STRONG/GUSTY SURFACE WINDS.
..IMY/STOPPKOTTE.. 06/25/2010
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