SWODY1
SPC AC 112001
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0301 PM CDT WED JUL 11 2007
VALID 112000Z - 121200Z
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
THE NORTHEASTERN STATES INTO THE DELMARVA...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING FROM
CNTRL GA INTO PORTIONS OF THE CNTRL/ERN CAROLINAS...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
OVER THE CNTRL HIGH PLAINS...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
NRN CA/SRN ORE...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
NRN MN...
..CNTRL HIGH PLAINS...
VISIBLE SATELLITE AND REGIONAL RADAR IMAGERY SHOW DEEPENING
CUMULUS/EARLY TSTM DEVELOPMENT OCCURRING OVER THE FRONT RANGE WITHIN
A STEEP LAPSE RATE ENVIRONMENT. RUC OBJECTIVE FIELDS SUGGESTS THAT
AIR MASS OVER THE ADJACENT HIGH PLAINS REMAINS CAPPED...THOUGH
RELATIVELY CLOUD-FREE SKIES ARE ALLOWING FOR STRONG BOUNDARY LAYER
HEATING. WITH TIME...EXPECT CAP TO ERODE SUCH THAT CONVECTION WILL
BEGIN TO MOVE/DEVELOP EWD INTO A POTENTIALLY MODERATELY UNSTABLE
ENVIRONMENT WITH MLCAPES OF 1000-1500 J/KG.
CURRENT PLATTEVILLE CO PROFILER INDICATES LIGHT SELY LOW-LEVEL FLOW
VEERING TO NWLY AND INCREASING TO 30 KT IN THE MID-LEVELS...AND
EVENTUALLY 40-50 KT IN THE 9-12 KT AGL LAYER. THIS TYPE OF PROFILE
IS MORE THAN SUFFICIENT TO SUPPORT SUPERCELL STRUCTURES CAPABLE OF
LARGE HAIL AND DAMAGING WINDS. CURRENTLY...THE STRONGER LOW-LEVEL
SHEAR RESIDES ALONG THE CO/KS BORDER...COINCIDENT WITH STRONGER SELY
SURFACE WINDS. SHOULD THIS STRONGER GRADIENT FLOW DEVELOP
WWD...ISOLATED TORNADO POTENTIAL SHOULD CORRESPONDINGLY INCREASE.
STORMS ARE EXPECTED TO GRADUALLY SPREAD EWD ACROSS ERN CO INTO WRN
AND PERHAPS CNTRL KS OVERNIGHT ALONG CONSOLIDATING...SECONDARY
FRONTAL SURGE MOVING SWD OUT OF THE NRN PLAINS.
FOR ADDITIONAL SHORT TERM GUIDANCE...PLEASE SEE MCD 1450.
..NORTHEASTERN STATES INTO THE DELMARVA...
TSTMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON WITH MID-LEVEL
MOIST PLUME STREAMING NWD AHEAD OF SHORT WAVE TROUGH LIFTING NEWD
THROUGH LOWER MI AND LAKE HURON. THESE STORMS ARE LARGELY FOCUSED
ALONG PRIMARY COLD FRONT FROM THE ERN SHORE OF LAKE ONTARIO SSWWD
THROUGH WRN PA/WV...AS WELL AS ALONG PRE-FRONTAL TROUGH FROM THE
HUDSON VALLEY INTO THE DELMARVA. CONSIDERABLE CLOUDINESS ATTENDANT
TO MID-LEVEL MOIST PLUME HAS LIMITED DAYTIME HEATING AND RESULTANT
AIR MASS DESTABILIZATION WITH MLCAPES GENERALLY AROUND 500 J/KG.
LOCALLY STRONGER DIABATIC HEATING HAS OCCURRED FROM THE DE RIVER
VALLEY SWD TO CHESAPEAKE BAY WHERE MLCAPES HAVE INCREASED TO
1000-1500 J/KG.
THE BELT OF STRONGER MID-LEVEL FLOW ASSOCIATED WITH LARGE-SCALE
TROUGH REMAINS TO THE W IN POST-FRONTAL AIR MASS OVER THE GREAT
LAKES...WITH MAINLY 25-35 KT SWLY FLOW AT 500 MB PRESENT ACROSS
SYSTEM WARM SECTOR. AS SUCH...VERTICAL SHEAR IS NOT PARTICULARLY
STRONG. NONETHELESS...SOME POTENTIAL WILL EXIST FOR LOCALLY
DAMAGING WIND GUSTS THIS AFTERNOON AND EVENING...ESPECIALLY IF
STORMS CAN ORGANIZE A COLD POOL.
..SRN APPALACHIANS INTO CAROLINA PIEDMONT AND COASTAL PLAIN...
SRN EXTENSION OF MID-LEVEL SHEAR AXIS OR SEPARATE VORTICITY MAXIMUM
IS TRANSLATING EWD THROUGH THE SRN APPALACHIANS THIS AFTERNOON WITH
AN ACCOMPANYING BELT OF 30-35 KT LOW TO MID-LEVEL FLOW ASSOCIATED
WITH THIS FEATURE. TSTMS HAVE BECOME INCREASINGLY NUMEROUS THIS
AFTERNOON ALONG PRE-FRONTAL TROUGH FROM THE CNTRL CAROLINAS SWWD
INTO CNTRL/SRN GA AND SRN AL. AMBIENT INFLOW AIR MASS HAS BECOME
QUITE WARM WITH TEMPERATURES IN THE LOWER 90S...AND WHEN COUPLED
WITH DEWPOINTS IN THE UPPER 60S TO LOWER 70S...ENVIRONMENT HAS
BECOME MODERATELY UNSTABLE WITH MLCAPES OF 1000-2000 J/KG.
WHILE SOME SEVERE HAIL WILL BE POSSIBLE...THE PRIMARY SEVERE WEATHER
THREAT IS EXPECTED TO BE DAMAGING WINDS GIVEN THE
DEEP...UNDIRECTIONAL WIND FIELDS AND POTENTIAL FOR MOMENTUM
TRANSFER/DOWNSHEAR COLD POOL ELONGATION. THIS THREAT WILL LIKELY
CONTINUE INTO THE EVENING EWD TOWARD THE GA/CAROLINA COASTS.
..SRN ORE/NRN CA...
WATER VAPOR IMAGERY SHOWS STRONG SHORT WAVE TROUGH PIVOTING NWD
THROUGH NRN CA...WITH THIS FEATURE CONTINUING NWWD THROUGH WRN ORE
LATER THIS AFTERNOON INTO EVENING. DAYTIME HEATING HAS ALLOWED
TEMPERATURES TO WARM INTO THE 80S...WHICH WHEN COUPLED WITH
DEWPOINTS IN THE 50S IS RESULTING IN SBCAPES OF 500-1000 J/KG.
SUFFICIENT VERTICAL SHEAR EXISTS TO SUPPORT A FEW ORGANIZED STORMS
CAPABLE OF SEVERE HAIL AND/OR LOCALLY STRONG WIND GUSTS.
FOR ADDITIONAL SHORT TERM GUIDANCE ON THIS AREA...PLEASE SEE MCD
1451.
..NRN MN...
WIDELY SCATTERED TSTMS HAVE DEVELOPED TODAY FROM PARTS OF FAR SERN
SK/WRN ONTARIO INTO NRN MN IN ASSOCIATION WITH STRONG SHORT WAVE
TROUGH DIGGING SEWD THROUGH SK. WHILE LOW-LEVEL AIR MASS REMAINS
RELATIVELY COOL WITH TEMPERATURES IN THE 60S TO AROUND 70F...SO ARE
MID-LEVEL TEMPERATURES /AROUND -20 C AT 500 MB/ WHICH IS RESULTING
IN RELATIVELY STEEP LOW/MID-LEVEL LAPSE RATES AND SBCAPES OF
500-1000 J/KG. THIS INSTABILITY COUPLED WITH DEEP NWLY WIND FIELDS
INDICATE POTENTIAL FOR SOME SEVERE HAIL...BUT MORE SO LOCALLY
DAMAGING WIND GUSTS. THIS SEVERE POTENTIAL MAY CONTINUE INTO THE
EVENING...PRIOR TO DIMINISHING AS BOUNDARY LAYER COOLS/STABILIZES
WITH THE LOSS OF DAYTIME HEATING.
.MEAD.. 07/11/2007
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