The SPC is forecasting ...severe thunderstorms expected over parts of the southeast us through this evening.... Please read the latest public statement about this event.
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SPC AC 151940 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0240 PM CDT SAT MAR 15 2008 VALID 152000Z - 161200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF NRN GA AND SC... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NRN AND CNTRL GA...SC AND SRN NC... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE TN VALLEY...SRN APPALACHIAN MTNS AND CAROLINAS... ...REGIONAL TORNADO OUTBREAK IS IN PROGRESS ACROSS NRN GA AND SC WILL CONTINUE FOR THE REMAINDER OF THE AFTERNOON INTO THE EARLY EVENING... ...SRN ATLANTIC SEABOARD/ERN TN VALLEY... LATEST WATER VAPOR IMAGERY SHOWS A LOW AMPLITUDE PROGRESSIVE SHORTWAVE TROUGH LOCATED ACROSS THE LOWER MS VALLEY. A MORE SUBTLE LEAD SHORTWAVE TROUGH IS ALSO EVIDENT OVER THE UPPER TN VALLEY AND LIFT ASSOCIATED WITH THIS FEATURE IS AIDING INTENSE CONVECTIVE DEVELOPMENT ACROSS NRN GA AND FAR WRN SC. THE THUNDERSTORMS ARE LOCATED ALONG A QUASI-STATIONARY FRONT EXTENDING EWD FROM THE ATLANTA METRO AREA TO JUST SOUTH OF GREENVILLE SC. A CLUSTER OF SUPERCELLS WILL CONTINUE TO MOVE EWD ALONG THE BOUNDARY AND REACH THE COLUMBIA SC AREA BY LATE AFTERNOON. SOUTH OF THE BOUNDARY...RUC ANALYSIS INDICATES A SLIGHT CAPPING INVERSION EXISTS ACROSS ECNTRL GA AND THIS CAP SHOULD WEAKEN QUICKLY OVER THE NEXT 1 TO 2 HOURS. AS THIS HAPPENS...CONVECTIVE INITIATION WILL CONTINUE TO OCCUR BETWEEN ATLANTA AND MACON GA THIS AFTERNOON WITH A SEVERE CONVECTIVE CLUSTER MOVING EWD INTO ECNTRL GA LATE THIS AFTERNOON INTO EARLY THIS EVENING. SHORT-TERM MODEL FORECASTS AND RECENT RADAR TRENDS ARE IN GENERAL AGREEMENT WITH THIS SCENARIO AND SEVERE STORM COVERAGE SHOULD GRADUALLY INCREASE ACROSS THE REGION OVER THE NEXT 3 TO 6 HOURS. CONCERNING THE SHEAR ENVIRONMENT...LATEST RUC ANALYSIS HAS A 50 TO 60 KT LOW-LEVEL JET EXTENDING NEWD FROM THE FL PANHANDLE INTO CNTRL GA. THIS FEATURE WILL MOVE EWD ACROSS SCNTRL GA THIS AFTERNOON INCREASING LOW-LEVEL SHEAR ACROSS THE HIGH RISK AREA. FORECAST SOUNDINGS AT AUGUSTA GA SHOW CURVED HODOGRAPHS AND INCREASE 0-3 KM STORM RELATIVE HELICITIES FROM ABOUT 300 M2/S2 AT 19Z TO ABOUT 450 M2/S2 AT 21Z SUGGESTING LOW-LEVEL SHEAR WILL BECOME INCREASINGLY FAVORABLE FOR TORNADOES OVER THE NEXT FEW HOURS. IN ADDITION...SHORT-TERM MODEL FORECASTS SUGGEST LCL HEIGHTS WILL DROP ACROSS THE HIGH RISK AREA AS MOISTURE ADVECTION BRINGS SFC DEWPOINTS INTO THE MID 60S F MAKING CONDITIONS MORE FAVORABLE FOR STRONG TORNADOES. STRONG TORNADOES WILL BE POSSIBLE IN THE CORRIDOR FROM ATHENS GA SEWD TO THE AUGUSTA GA AREA AND EWD TO NEAR COLUMBIA SC LATE THIS AFTERNOON INTO EARLY THIS EVENING. SUPERCELLS AND BOW ECHOES WILL ALSO BE CAPABLE OF PRODUCING VERY LARGE HAIL AND DAMAGING WIND GUSTS OVER 80 KT. MODEL FORECASTS GRADUALLY DRIVE THE MCS EWD INTO ERN SC AND ACROSS NC SUGGESTING THE TORNADO...WIND DAMAGE AND LARGE HAIL THREAT SHOULD EXPAND EWD INTO THE I-95 CORRIDOR BY EARLY TO MID EVENING. ...TN VALLEY... A LINE OF CONVECTION IS ONGOING ACROSS MIDDLE TN AND NRN AL WHICH IS ASSOCIATED WITH THE MAIN UPPER-LEVEL TROUGH EXITING THE LOWER MS VALLEY ATTM. AS SFC DEWPOINTS GRADUALLY INCREASE AND MODERATE INSTABILITY DEVELOPS ACROSS NRN AL...THE SEVERE THREAT SHOULD GRADUALLY EXPAND EWD ACROSS THE I-65 CORRIDOR. STRONG VERTICAL SHEAR SHOWN BY RUC ANALYSIS AND COLD AIR ALOFT ON FORECAST SOUNDINGS SUGGESTS THE PRIMARY THREAT WITH THE ACTIVITY WILL BE LARGE HAIL. ..BROYLES.. 03/15/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z