The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains later today through thursday morning.... Please read the latest public statement about this event.
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SPC AC 091246 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0746 AM CDT WED APR 09 2008 VALID 091300Z - 101200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM CNTRL AND N TX INTO SRN AND ERN OK... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE TX BIG BEND INTO SRN KS...THE OZARK...AND THE LWR TN VLY... ...START OF A MAJOR TWO-DAY SVR WX OUTBREAK TO BEGIN LATER TODAY... ...SYNOPSIS... STRONG AZ/NV TROUGH WILL AMPLIFY INTO A CLOSED LOW LATER THIS PERIOD AS 130 KT NLY JET STREAK NOW OVER NRN CA CONTINUES SSEWD. THE LOW SHOULD REACH SE CO BY 12Z THURSDAY AS ASSOCIATED 100 KT MID-LEVEL JET STREAK REDEVELOPS ON SE SIDE OF SYSTEM OVER N TX/OK. AT LOWER LEVELS...SFC MAP ATTM SHOWS A SHALLOW COLD AIR MASS CONTINUING TO NOSE WSW ACROSS OK INTO PARTS OF WRN/NRN TX. THE COOL AIR MASS WILL BE REINFORCED BY EVAPORATIVE COOLING FROM ELEVATED TSTMS THAT LIKELY WILL EXPAND IN COVERAGE THROUGH MUCH OF THE DAY. NEVERTHELESS...LEE CYCLOGENESIS SHOULD GET UNDERWAY LATE THIS AFTN AND TONIGHT ALONG SW END OF THE STALLING FRONT OVER SW TX. THE LOW SHOULD THEN ACCELERATE NNE TO NEAR OKC BY THE END OF THE PERIOD AS POTENT VORT MAX ASSOCIATED WITH APPROACHING UPR SYSTEM RAPIDLY ENHANCES UVV ACROSS REGION. ...TX/OK INTO PARTS OF SRN KS/AR/SW MO... ELEVATED TSTMS NOW FORMING IN NW TX LIKELY WILL EXPAND IN COVERAGE/INTENSITY THROUGH THE DAY AS ENVIRONMENT ABOVE SHALLOW COOL DOME FURTHER WARMS AND MOISTENS. STEEP MID LEVEL LAPSE RATES ON AREA SOUNDINGS...COUPLED WITH QUALITY OF ELEVATED MOISTURE INFLOW /850 MB DEWPOINTS AOA 12C/ AND 40+ KT SWLY CLOUD-LAYER SHEAR WILL SUPPORT SUSTAINED ROTATING STORMS WITH LARGE HAIL AS THE ACTIVITY MOVES/DEVELOPS NE INTO MUCH OF OK/SRN KS. ALONG SRN FRINGE OF ABOVE STORMS...POTENTIAL WILL INCREASE FOR THE DEVELOPMENT OF SFC-BASED STORMS AS SFC HEATING DESTABILIZES REGION ALONG AND S OF SFC FRONT STALLING OVER N CNTRL TX. WITH SBCAPE INCREASING TO ABOVE 2500 J/KG AND 40-50 KT DEEP WSWLY SHEAR...ENVIRONMENT SHOULD PROVE FAVORABLE FOR SCTD DISCRETE TO SEMI-DISCRETE SUPERCELLS. THESE COULD PRODUCE TORNADOES...IN ADDITION TO VERY LARGE HAIL AND DMGG WIND...GIVEN RICH MOISTURE INFLOW AND LIKELIHOOD FOR SLIGHTLY-BACKED NEAR-SFC FLOW. FARTHER E...A FEW STRONG TO LOCALLY SVR STORMS MAY ALSO FORM E ALONG SAME FRONT INTO SOMEWHAT LESS UNSTABLE/LESS STRONGLY-SHEARED ENVIRONMENT OVER AR AND THE LWR TN VLY. LATE TODAY AND EARLY TONIGHT...ARRIVAL OF STRONG FORCING FOR ASCENT ASSOCIATED WITH APPROACHING UPR VORT SHOULD SUPPORT A NEW ROUND OF SUPERCELL DEVELOPMENT OVER W TX. SOME OF THESE STORMS LIKELY WILL REMAIN SLIGHTLY ELEVATED ABOVE RETREATING COOL DOME...ESPECIALLY IN NW TX/FAR WRN OK. BUT THOSE NEAR AND S OF PATH OF DEVELOPING SFC LOW WILL BE SFC-BASED...AND WILL HAVE ACCESS TO A VERY UNSTABLE AND VERY STRONGLY SHEARED ENVIRONMENT /SBCAPE TO 3000 J PER KG AND 50-60 KTS DEEP SWLY SHEAR/. THUS...TORNADOES...VERY LARGE HAIL AND HIGH WIND ARE LIKELY. STRENGTH OF THE FORCING FOR ASCENT...PROGRESSIVE NATURE OF THE ASCENT...STRENGTHENING WIND FIELD...AND QUALITY OF MOISTURE INFLOW ALL SUGGEST THAT THE STORMS WILL QUICKLY ORGANIZE INTO A SQLN/POSSIBLE DERECHO. EMBEDDED SUPERCELLS LIKELY WILL CONTINUE TO POSE A THREAT FOR TORNADOES AS THE HIGH-WIND-PRODUCING CONVECTIVE SYSTEM SWEEPS E/NE ALONG RETREATING SFC FRONT INTO NE TX...SRN/ERN OK AND PERHAPS PARTS OF AR/SW MO THROUGH EARLY THURSDAY. ..CORFIDI/HURLBUT.. 04/09/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z