The SPC is forecasting ...severe thunderstorms with widespread damaging winds and several tornadoes expected over parts of the lower ohio valley...mid south...and lower mississippi valley through tonight.... Please read the latest public statement about this event. View What is a Watch? clip.
| 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 291956 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0156 PM CST TUE JAN 29 2013 VALID 292000Z - 301200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM EXTREME NERN TX...NRN LA...EXTREME SERN OK...MOST OF AR...SERN MO...SRN IL...WRN KY...WRN TN AND NWRN MS... ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN PORTIONS OF THE SRN PLAINS INTO THE LOWER AND MID MS VALLEY...TN VALLEY AND A PORTION OF THE OH VALLEY... ...NERN TX THROUGH LOWER MS VALLEY WRN TN AND SWRN OH VALLEY... NOT MUCH CHANGE TO THE CURRENT FORECAST AS IT STILL APPEARS THAT A SIGNIFICANT SEVERE WEATHER EVENT MAY EVOLVE ACROSS THE LOWER MS VALLEY INTO WRN PORTIONS OF THE TN AND OH VALLEYS...ESPECIALLY THIS EVENING INTO TONIGHT. THIS INCLUDES THE POTENTIAL FOR TORNADOES...A FEW OF WHICH COULD BE STRONG AND NUMEROUS DAMAGING WIND EVENTS. SFC LOW OVER NERN OK WILL DEEPEN AND LIFT NEWD THROUGH THE MID MS VALLEY WITHIN EXIT REGION OF STRENGTHENING UPPER JET ROUNDING THE BASE OF THE TROUGH. INTENSE 60-70 KT LLJ WILL DEVELOP EWD THROUGH THE LOWER MS VALLEY CONTRIBUTING TO DESTABILIZATION AS LOW-MID 60S DEWPOINTS ARE ADVECTED NWD THROUGH THE BOUNDARY LAYER. THE 18Z SOUNDINGS FROM SHV AND LZK ALREADY INDICATE LOW 60S NEAR SFC DEWPOINTS AND WEAK SFC BASED INSTABILITY...BUT WITH AN INVERSION AROUND 700 MB. THIS INVERSION WILL LIKELY BE ELIMINATED AS THE ATMOSPHERE COMES UNDER THE INFLUENCE OF LARGE SCALE ASCENT DOWNSTREAM FROM THE PROGRESSIVE TROUGH. RADAR DATA ALSO INDICATE EVIDENCE OF A GRAVITY WAVE MOVING THROUGH ERN TX INTO THE LOWER MS VALLEY. SQUALL LINE FROM ERN OK THROUGH CNTRL/SWRN TX IS EXPECTED TO INTENSIFY AS IT DEVELOPS EAST AND INTERACTS WITH THE MOIST AXIS. EMBEDDED SUPERCELLS...BOWING SEGMENTS AND MESO-VORTICES APPEAR LIKELY WITH A THREAT OF DAMAGING WIND AND TORNADOES. OTHER ORGANIZED SEVERE STORMS MAY DEVELOP AHEAD OF THE LINE WITHIN THE MOISTENING WARM SECTOR AND IN ASSOCIATION WITH THE INTENSIFYING LLJ ACROSS A PORTION OF THE LOWER MS VALLEY AND WRN TN TONIGHT. SOME OF THESE STORMS COULD EVOLVE INTO DISCRETE SUPERCELLS WITH A RISK FOR TORNADOES. ..DIAL.. 01/29/2013 .PREV DISCUSSION... /ISSUED 1020 AM CST TUE JAN 29 2013/ ...ERN OK/TX TO THE MS AND OH VALLEYS THROUGH TONIGHT... A LARGE-SCALE MID-UPPER TROUGH OVER THE HIGH PLAINS WILL PROGRESS EWD OVER THE LOWER PLAINS TO THE MS VALLEY BY EARLY WEDNESDAY. WITHIN THE LARGE TROUGH...A PRIMARY SHORTWAVE TROUGH OVER THE SRN HIGH PLAINS...WITH AN ASSOCIATED 100 KT MIDLEVEL JET...WILL EJECT ENEWD TOWARD ERN OK/NW AR/MO OVERNIGHT. LIKEWISE...AN ASSOCIATED SURFACE CYCLONE NOW IN N CENTRAL OK WILL DEEPEN AND MOVE NEWD ACROSS MO/IL TO LOWER MI...ALONG A PRE-EXISTING BAROCLINIC ZONE. MEANWHILE...A BROAD MOIST SECTOR IS ALREADY ESTABLISHED FROM ERN TX/OK TO THE LOWER AND MID MS VALLEY REGION...WHERE BOUNDARY LAYER DEWPOINTS RANGE FROM THE UPPER 60S ALONG THE NW GULF COAST...TO 56-60 F FARTHER N INTO MO/IL. ADDITIONAL EWD EXPANSION OF THE MOIST SECTOR IS LIKELY THROUGH TONIGHT ACROSS THE MS/TN AND LOWER OH VALLEY REGION...IN RESPONSE TO THE DEEPEN CYCLONE AND A STRENGTHENING SLY LLJ. WIDESPREAD CONVECTION IS ONGOING ALONG AND JUST AHEAD OF THE SURFACE COLD FRONT FROM CENTRAL OK TO NRN MO. THOUGH EXTENSIVE CLOUDS ARE PRESENT THROUGH MUCH OF THE WARM SECTOR...CONTINUED MOISTURE ADVECTION FROM THE S AND MODEST SURFACE HEATING IN CLOUD BREAKS WILL BOOST MLCAPE VALUES TO THE 1000-2000 J/KG RANGE ACROSS E TX AND SE OK THIS AFTERNOON...WITH LESSER BUOYANCY FARTHER TO THE E AND NE. THERE ARE ALREADY INDICATIONS THAT ADDITIONAL PRE-FRONTAL CONVECTION WILL DEVELOP FROM NE TX INTO SE OK/WRN AR AND EVENTUALLY SRN MO THIS AFTERNOON ALONG THE MOIST AXIS. VERTICAL SHEAR PROFILES WILL BE FAVORABLE FOR SUPERCELLS WITH AN ATTENDANT RISK FOR TORNADOES AND DAMAGING WINDS ACROSS THIS CORRIDOR. FARTHER N...CONVECTION WILL GRADUALLY EVOLVE INTO A WELL-DEVELOPED QLCS WITH AN INCREASING RISK FOR DAMAGING WINDS LATER THIS AFTERNOON INTO EARLY TONIGHT...WITH A RISK OF EMBEDDED MESOVORTICES AND TORNADOES. THE GREATEST SEVERE RISK IS EXPECTED THIS EVENING THROUGH TONIGHT...BEGINNING AS THE PRE-FRONTAL CONVECTION NEAR AND NW OF THE ARKLATEX...AND CONTINUING OVERNIGHT AS ADDITIONAL PRE-FRONTAL CONVECTION FORMS WITHIN ONE OR MORE WARM SECTOR CONFLUENCE BANDS NEAR THE MS RIVER. VERTICAL SHEAR WILL BE EXTREMELY STRONG WITHIN A MOIST ENVIRONMENT WITH AT LEAST WEAK SURFACE-BASED INSTABILITY. THOUGH MLCAPE MAY ONLY REACH 500-750 J/KG...EFFECTIVE SRH OF 500-700 M2/S2 IN ASSOCIATION WITH A 70-80 KT LLJ WILL SUPPORT THE POTENTIAL FOR A FEW STRONG TORNADOES WITH FAST-MOVING PRE-FRONTAL SUPERCELLS...AS WELL AS CIRCULATIONS EMBEDDED WITHIN WHAT WILL BECOME A WELL-FORMED SQUALL LINE. WIDESPREAD AND SIGNIFICANT DAMAGING WINDS WILL ALSO BE POSSIBLE AS FAR NE AS THE LOWER OH VALLEY...WHERE 80+ KT FLOW JUST ABOVE THE SURFACE WILL COINCIDE WITH AT LEAST WEAK SURFACE-BASED BUOYANCY THROUGH MOST OF THE NIGHT. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z