The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains later today and tonight.... Please read the latest public statement about this event.
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SPC AC 132001 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0301 PM CDT FRI APR 13 2007 VALID 132000Z - 141200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST TEXAS THROUGH THIS EVENING... ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK ACROSS NRN/ERN TX...PARTS OF FAR SRN OK TO SWRN AR AND NRN/WRN LA... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK ACROSS THE SRN PLAINS TO THE LOWER MS VALLEY... ...THREAT FOR ACTIVE SEVERE WEATHER WITH POTENTIAL FOR A FEW SIGNIFICANT TORNADOES...VERY LARGE AND DESTRUCTIVE HAIL...AND DAMAGING WINDS BECOMING MORE PROBABLE ACROSS NORTH CENTRAL TO NORTHEAST TX INTO THIS EVENING... STRONG MID LEVEL SHORT WAVE TROUGH LOCATED OVER ERN HALF OF NM IS PROGGED TO MOVE ENEWD THIS FORECAST PERIOD ACROSS THE SRN PLAINS AND SHOULD REACH THE OZARKS/LOWER MO VALLEY BY 12Z SATURDAY...WITH LONG WAVE TROUGH EDGING EWD INTO THE SRN PLAINS. ASCENT AHEAD OF THESE FEATURES AND ATOP MODIFYING AIR MASS WILL SUPPORT AN ACTIVE SEVERE WEATHER EVENT ACROSS PARTS OF N TX TO NRN LA THROUGH TONIGHT...WITH A RISK OF A FEW STRONG TO SIGNIFICANT TORNADOES... VERY LARGE HAIL AND DAMAGING WINDS. THUS...A HIGH RISK HAS BEEN ADDED TO THE CONVECTIVE OUTLOOK ACROSS PARTS OF NORTH CENTRAL TO NE TX. AFTERNOON WATER VAPOR IMAGERY INDICATED A LEAD SHORT WAVE TROUGH CENTERED OVER THE TX/OK PANHANDLES. ATTENDANT DEEP LAYER ASCENT WITH THIS FEATURE IS AIDING STRONG/SEVERE TSTM DEVELOPMENT VICINITY OF SURFACE LOW SWD ALONG WIND SHIFT/DRY LINE IN NW TX. ALTHOUGH THIS LEAD WAVE IS PROGGED TO MOVE NEWD INTO KS...A SECOND ZONE OF ASCENT NOW MOVING INTO TX AHEAD OF PRIMARY NM SHORT WAVE TROUGH WILL SPREAD EWD ACROSS TX/OK TOWARD THE LOWER MS VALLEY MAINTAINING TSTM DEVELOPMENT THROUGH THE FORECAST PERIOD ALONG/E OF DRY LINE. EARLY AFTERNOON SURFACE ANALYSIS SHOWED A LOW/TRIPLE POINT OVER NW TX /VICINITY STONEWALL COUNTY/ WITH A WARM FRONT EXTENDING SEWD TO SOUTH OF FTW/DAL METRO AREA TO NORTH OF HOU. DRYLINE EXTENDED SSWWD FROM SURFACE LOW TO THE TX BIG BEND REGION. SURFACE LOW SHOULD TRACK ENEWD ALONG THIS WARM FRONT AND BE LOCATED ALONG/JUST EAST OF THE ARKLATEX REGION BY 12Z SUNDAY. BROAD 50 KT SLY LLJ LOCATED OVER THE ERN HALF OF TX INTO LA WILL MAINTAIN INFLUX OF RICH GULF MOISTURE ACROSS THE WARM SECTOR...AS WARM FRONT CONTINUES TO SHIFT N TOWARD THE RED RIVER VALLEY AND EVENTUALLY INTO NRN LA/SRN AR AND SWRN MS LATER THIS EVENING. STEEP LAPSE RATES ATOP THIS MOISTURE RETURN COMBINED WITH ADDITIONAL SURFACE HEATING ALONG/E OF DRY LINE WILL SUPPORT MODERATE INSTABILITY DEVELOPING/EXPANDING EWD INTO CENTRAL/NRN PARTS OF TX. DEEP LAYER SHEAR WILL REMAIN SUPPORTIVE FOR ORGANIZED STORMS THIS AFTERNOON INTO THE EVENING WITH POTENTIAL FOR LONG-LIVED TORNADIC SUPERCELLS VICINITY OF SURFACE LOW AND WARM FRONT...WHERE 0-3 KM SRH VALUES IN EXCESS OF 400 M2/S2 WILL FAVOR LOW LEVEL ROTATIONS WITHIN MOISTENING AIR MASS. SEVERE THREAT IS EXPECTED TO SPREAD EWD OVERNIGHT INTO THE LOWER MS VALLEY WITH POTENTIAL FOR MORE LINEAR STRUCTURE AS SHEAR VECTORS BECOME ORIENTED MORE PARALLEL TO PROGRESSIVE COLD FRONT. NORTH OF THE WARM FRONT...SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO INCREASE THROUGH THE AFTERNOON/EVENING FROM SRN OK EWD TO PARTS OF AR/NRN MS...AHEAD OF APPROACHING UPPER TROUGH. ELEVATED SUPERCELLS ARE POSSIBLE OVER THIS REGION...ABOVE STABLE BOUNDARY LAYER...WITH LARGE HAIL BEING THE MAIN THREAT. ..PETERS.. 04/13/2007 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z