| Categorical Graphic |
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| Probabilistic Tornado Graphic |
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
| Probabilistic Damaging Wind Graphic |
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
| Probabilistic Large Hail Graphic |
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
SPC AC 291300 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0700 AM CST WED FEB 29 2012 VALID 291300Z - 011200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE TN VLY AND SRN APPALACHIANS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE LWR MS VLY INTO THE OH VLY AND VA/NC... ...SYNOPSIS... STRONG NW IA UPR LOW WILL CONTINUE ENE TO CNTRL WI THIS EVE...BEFORE SHEARING E TO THE LWR GRT LKS EARLY THU. ATTENDANT VORT LOBE LARGELY ASSOCIATED WITH OVERNIGHT SQLN/SUPERCELLS NOW IN THE LWR OH VLY SHOULD CONTINUE NNE INTO MI AND WEAKEN...WHILE UPSTREAM VORT LOBE NOW OVER ERN NEB SWEEPS ESE INTO IND/KY LATER TODAY...AND OFF THE MID ATLANTIC CST THU MORNING. AT LWR LVLS...COLD FRONT ASSOCIATED WITH IA UPR LOW EXPECTED TO ACCELERATE ESE INTO THE LWR OH AND TN VLYS LATER TODAY AS UPSTREAM VORT LOBE CONTINUES ESEWD. FRONT WILL BE PRECEDED BY NE/SW SQLN/OUTFLOW BOUNDARY LEFT BY OVERNIGHT STORMS...AND THIS LATTER FEATURE LIKELY WILL SERVE AS THE EFFECTIVE BOUNDARY FOR LOW LVL UPLIFT/TSTM DEVELOPMENT THROUGH TODAY. FARTHER NE...DIFFUSE WARM FRONT SHOULD ADVANCE NEWD ACROSS OH...THE CNTRL APPALACHIANS...AND VA/SRN MD...WITH A SECONDARY SFC WAVE POSSIBLY FORMING ALONG THE BOUNDARY EARLY THU NEAR THE DELMARVA PENINSULA. ...LWR MS VLY NEWD THROUGH TN VLY INTO MID OH VLY/CAROLINAS... NE/SE SQLN WITH EMBEDDED SUPERCELLS...NOW EXTENDING FROM SRN IND TO NRN AR...EXPECTED TO CONTINUE EWD THROUGH THIS MORNING. GIVEN RECOVERING BOUNDARY LAYER AHEAD OF SQLN /ASSOCIATED WITH 50-60 KT SWLY LLJ/...AND STRENGTH OF WIND FIELD ASSOCIATED WITH SE FRINGE OF IA UPR LOW /500 MB WSW FLOW AOA 70 KTS/...SETUP APPEARS FAVORABLE FOR MAINTENANCE OF EXISTING SUPERCELLS WITH AN ATTENDANT RISK FOR TORNADOES/DMGG WIND. MORNING SOUNDINGS AT LITTLE ROCK AND NASHVILLE SUGGEST THAT ONSET OF DAYTIME HEATING MAY SUPPORT REJUVENATION OF EXISTING SQLN STORMS IN KY AND NRN TN...AND POSSIBLY NEW DEVELOPMENT FARTHER SW ALONG AFOREMENTIONED OUTFLOW BOUNDARY/WIND SHIFT LINE ASSOCIATED WITH THE STORMS. SATELLITE DERIVED /GPS PW DATA...AND OBSERVED SFC DEWPOINTS... SUGGEST THAT DEEPLY MOIST LOW LVL ENVIRONMENT WILL BE PRESENT OVER THE TN VLY. COUPLED WITH STRONG TO INTENSE LOW TO MID LVL WIND FIELD...AND THE GRAZING INFLUENCE OF UPSTREAM VORT LOBE THIS AFTN...POTENTIAL WILL EXIST FOR A FAIRLY CONCENTRATED CORRIDOR OF SUPERCELLS FROM NRN MS ENEWD TO THE WRN SLOPES OF THE CNTRL/SRN APPALACHIANS. A FEW OF THESE STORMS MAY BECOME LONG-LIVED AND CAPABLE OF TORNADOES /ONE OR TWO OF WHICH COULD BE STRONG/...AND SWATHS OF DMGG WIND. THE STORMS SHOULD EVOLVE INTO A BROKEN QUASI-LINEAR MCS LATER THIS AFTN AND TNGT. PART OF THE THIS SYSTEM MAY MOVE/DEVELOP E TO VICINITY OF WARM FRONT IN SRN VA/NC...POSING AN OVERNIGHT SVR RISK /INCLUDING ISOLD TORNADOES/ IN THAT REGION. THE OTHER PART OF THE MCS MAY TEND TO BACK-BUILD AND/OR DEVELOP MORE SWD INTO NRN AL/GA...WITH A DIMINISHING THREAT FOR SVR WEATHER CONTINUING INTO EARLY THU. FINALLY...N OF THE OH VLY SQLN...APPROACH OF UPSTREAM VORT LOBE AND ASSOCIATED COLD FRONT MAY SUPPORT A FEW STORMS...POSSIBLY SVR...THIS AFTN/EARLY TNGT IN ERN IND AND OH/WRN PA. ..CORFIDI/DEAN.. 02/29/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z