DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0728 AM CDT THU MAY 17 2012 VALID 171300Z - 181200Z ...NO SVR TSTM AREAS FORECAST... ...SE ATLANTIC STATES TODAY... A MIDLEVEL TROUGH OVER GA AND THE NE GULF OF MEXICO WILL EVOLVE INTO A WEAK CLOSED AS IT DRIFTS EWD TO THE SE ATLANTIC COAST...WHILE WEAK SURFACE CYCLOGENESIS IS EXPECTED OFFSHORE BY EARLY FRIDAY. MEANWHILE...CLOUD BREAKS FROM CENTRAL FL NWD TO THE COASTAL PLAINS OF SE GA/SC WILL ALLOW SURFACE HEATING/ DESTABILIZATION LATER THIS MORNING. BOUNDARY LAYER DEWPOINTS IN THE MID 60S N AND UPPER 60S S...AS WELL AS COOL 500 MB TEMPERATURES OF -11 TO -14 C...WILL CONTRIBUTE TO MLCAPE VALUES OF 1000-1500 J/KG. STORM DEVELOPMENT IS EXPECTED BY MID-LATE MORNING AS THE LOW LEVELS WARM AND ANY LINGERING CONVECTIVE INHIBITION IS REMOVED...WITH GREATER STORM COVERAGE IN ASSOCIATION WITH THE ATLANTIC COAST SEA BREEZE. HERE...VERTICAL SHEAR WILL BE A LITTLE STRONGER THAN ELSEWHERE /ESPECIALLY ACROSS FL IN PROXIMITY TO THE UPPER JET/...AND THE STRONGEST STORMS COULD PRODUCE ISOLATED STRONG/DAMAGING WINDS AND HAIL APPROACHING ONE INCH IN DIAMETER. THE MARGINAL SEVERE STORM RISK WILL BE DIURNAL IN NATURE...WITH AN END TO THE RISK EXPECTED AROUND SUNSET. ...CENTRAL HIGH PLAINS AND NRN ROCKIES THIS AFTERNOON/EVENING... A WEAKENING MIDLEVEL TROUGH WILL DRIFT EWD FROM CO TO WRN KS BY EARLY TONIGHT...AS AN UPSTREAM WAVE PROGRESSES INLAND TO THE GREAT BASIN...AND A SEPARATE NRN STREAM TROUGH CROSSES BC/AB. LEE CYCLOGENESIS WILL MAINTAIN A SLY LLJ ACROSS THE PLAINS THROUGH THE PERIOD. HOWEVER...MOISTURE RETURN TODAY WILL BE LIMITED AS SURFACE DEWPOINTS GENERALLY RANGE FROM THE LOW 40S IN ND TO THE MID 50S IN SRN OK/N TX. STRONG DAYTIME HEATING/MIXING ALONG THE LEE TROUGH WILL PROMOTE THE DEVELOPMENT OF WEAK INSTABILITY WITH MINIMAL CONVECTIVE INHIBITION...AND A FEW HIGH-BASED STORMS MAY FORM LATE THIS AFTERNOON/EVENING ACROSS THE HIGH PLAINS. VERTICAL SHEAR WILL REMAIN MARGINAL AND PW VALUES SHOULD NOT EXCEED 0.50-0.70 INCHES...BUT INVERTED-V PROFILES COULD SUPPORT ISOLATED MICROBURSTS. A SEPARATE AREA OF CONVECTION IS EXPECTED ACROSS THE NRN ROCKIES AREA IN ADVANCE OF THE APPROACHING MIDLEVEL TROUGH. LIKE THE HIGH PLAINS...MOISTURE/INSTABILITY WILL BE LIMITED. STILL...STEEP LOW-LEVEL LAPSE RATES AND MODEST DEEP-LAYER SWLY FLOW COULD SUPPORT STRONG GUSTS WITH HIGH-BASED STORMS THIS AFTERNOON/EVENING...MAINLY INVOF THE MT/WY/ID BORDER REGION. ..THOMPSON/HURLBUT.. 05/17/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1300.html
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