The SPC is forecasting ...widespread severe thunderstorms are expected over western ky and portions of nrn tn this afternoon.... Please read the latest public statement about this event.
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SPC AC 081712 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1212 PM CDT FRI MAY 08 2009 VALID 081630Z - 091200Z ...THERE IS A MDT RISK OF SVR TSTMS PORTIONS OF WRN KY AND NRN TN... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLAINS EWD THROUGH THE TN/LOWER OH VALLEYS EWD TO THE CAROLINAS... ...THERE IS A SLGT RISK OF SVR TSTMS IN THE IA AREA... ...TN/LOWER OH VALLEY... LONG LIVED BOW ECHO...MOVING EWD AT 60 KT...WAS APPROACHING THE MS RIVER AND IS EXPECTED TO TRACK MOSTLY EWD THROUGH THE REGION THIS AFTERNOON. THOUGH MESOSCALE MODELS SUGGEST WEAKENING WITH TIME...GIVEN THE WELL ORGANIZED SYSTEM MOVING INTO AN ENVIRONMENT WITH STRONG INSTABILITY...MLCAPES 2000-2500 J/KG...AND EFFECTIVE SHEAR NEAR 40 KT IS EXPECTED TO SUSTAIN WIDESPREAD WIND DAMAGE..SOMETIMES EXTREME. WIND AND HAIL IS FORECAST WITH THE SYSTEM UNTIL IT REACHES THE APPALACHIANS THIS EVENING. LOW LEVEL SHEAR WILL ALSO BE SUPPORTIVE OF TORNADOES...ESPECIALLY WITH THE ROTATING BOW HEADS. ...NRN TX/SERN OK/AR/NRN LA... COLD FRONT AT MID MORNING EXTENDED FROM SERN KS SWWD INTO WRN TX NEAR LBB. FRONT IS EXPECTED TO MOVE SEWD TO NEAR A SGF-ADM-MAF LINE BY 23Z. MORNING SOUNDINGS SHOWED STRONG CAPPING BETWEEN 850-700 MB...AND THIS SHOULD LIMIT CONVECTION ALONG THE FRONT THROUGH MOST OF THE DAY. DESPITE NO REAL DISCERNABLE SHORTWAVE TROUGH...MODELS DEPICT A SPEED MAX MOVING INTO THE REGION LATE THIS AFTERNOON WITH INCREASING DIFFLUENCE ALOFT. THIS WOULD RESULT IN STRENGTHENING LOW LEVEL CONVERGENCE ALONG THE FRONT... ESPECIALLY IN AND WEST OF THE ARKLATEX. ALL OPERATIONAL/MESOSCALE MODELS SHOW CONVECTION DEVELOPS ALONG THE FRONT IN ERN OK/NRN TX AFTER 22Z. STORMS THAT DEVELOP ARE LIKELY TO QUICKLY BECOME SEVERE GIVEN MLCAPES FROM 3000 TO 4000 J/KG AND MID LEVEL LAPSE RATES NEAR 9 C/KM INDICATE VERY LARGE HAIL WOULD BE THE MAIN THREAT. ...CAROLINAS..... REMNANT MCS FROM WRN NC INTO NERN GA IS EXPECTED TO CONTINUE EWD INTO A MOIST AND DESTABILIZING AIR MASS...2000 J/KG MLCAPE WITH TEMPERATURES IN THE 80S. ALTHOUGH ACTIVITY WILL GRADUALLY DEVELOP SOUTH OF THE STRONGER WINDS ALOFT...UNIDIRECTIONAL WLY WINDS AT 20 TO 30 KT THROUGH THE LOWER 6 KM MAY SUPPORT A LINEAR SYSTEM THIS AFTERNOON...WITH WIND DAMAGE THE PRIMARY THREAT. ...IA/NWRN IL AND SWRN WI... A STRONG SHORTWAVE TROUGH OVER CENTRAL NEB/SD WILL TRACK EWD TO NEAR THE NEB/IA BORDER BY 00Z. COLD TEMPERATURES ALOFT...500 MB TEMPERATURES FROM -18 TO -22C...MODERATELY STEEP LAPSE RATES...40-50 KT DEEP LAYER SHEAR AND LIFT ASSOCIATED WITH TROUGH/ASSOCIATED JET MAX SHOULD RESULT IN SUPERCELLS. HAIL AND WIND DAMAGE WILL BE THE MAIN THREATS. ..IMY/GRAMS.. 05/08/2009 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z