The SPC is forecasting ...severe thunderstorms expected over parts of the ozarks and lower mississippi valley into the lower tennessee and lower ohio valleys today through tonight.... Please read the latest public statement about this event.
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SPC AC 101634 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1134 AM CDT THU APR 10 2008 VALID 101630Z - 111200Z ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR NE LA...ERN AR...NW MS TO THE CONFLUENCE OF THE MS/OH RIVERS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT...FROM E TX/LA TO MID MS AND OH VALLEYS THROUGH TONIGHT... ...SYNOPSIS... THE STRONG MID LEVEL SHORTWAVE TROUGH IS EJECTING NEWD OVER THE TX PANHANDLE/WRN OK/SW KS AS OF LATE MORNING...WITH ASSOCIATED SURFACE CYCLONES IN EXTREME SW KS AND CENTRAL KS. THE TWO SURFACE CYCLONES SHOULD CONSOLIDATE INTO A SINGLE LOW THIS AFTERNOON IN CENTRAL KS...AND THE ENTIRE SYSTEM WILL LIFT NEWD TO IA AND MAINTAIN INTENSITY OVERNIGHT. SOME PARTIAL CLEARING IS OCCURRING ACROSS ERN OK/NE TX IN ADVANCE OF THE PACIFIC COLD FRONT...WITH MORE WIDESPREAD CLOUDS/COOLER TEMPERATURES FARTHER N INTO ERN KS/WRN MO. THE PROSPECTS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT ARE QUESTIONABLE ALONG THE COLD FRONT IN NE TX/ERN OK/WRN AR/SW MO/SE KS THIS AFTERNOON GIVEN A TENDENCY FOR DRYING WITH TIME. OTHER CLEARING IS OCCURRING IN A NARROW CORRIDOR ACROSS CENTRAL MO BEHIND THE OVERNIGHT CONVECTION. THUNDERSTORM DEVELOPMENT IS MORE PROBABLE HERE COMPARED TO AREAS FARTHER SW...THOUGH EXTREME VERTICAL SHEAR BENEATH THE MID-UPPER JET CORE MAY LARGELY OVERWHELM THE RELATIVELY WEAK BUOYANCY. ANY STORMS THAT FORM ACROSS CENTRAL/NE MO WILL SPREAD INTO IL THIS AFTERNOON/ EVENING...WITH AN ATTENDANT THREAT FOR DAMAGING WINDS/HAIL...AND PERHAPS A TORNADO OR TWO. THIS LEAVES THE PRIMARY SEVERE THREAT AREA ALONG THE PRE-FRONTAL TROUGH IN AR AND S OF THE SYNOPTIC WARM FRONT LIFTING NWD TOWARD SRN IL/INDIANA. ...LOWER MS AND OH VALLEYS THIS AFTERNOON INTO TONIGHT... A BAND OF PRE-FRONTAL CONVECTION IS WEAKENING GRADUALLY FROM NW LA NNEWD ACROSS CENTRAL AR INTO SE MO. THE EWD PROGRESS OF THIS BAND SHOULD CONTINUE TO SLOW DURING THE AFTERNOON AS THE DEEP SYNOPTIC CYCLONE OCCLUDES AND LIFTS NNEWD ACROSS CENTRAL KS. LOW-LEVEL MOISTENING WILL PERSIST IN ADVANCE OF THE PRE-FRONTAL CONVECTION AS MID-UPPER 60 BOUNDARY LAYER DEWPOINTS SPREAD NWD FROM LA INTO ERN AR/WRN MS/WRN TN...AND POSSIBLY SE MO THIS AFTERNOON. MEANWHILE...VERTICAL SHEAR WILL REMAIN QUITE STRONG IN THE WARM SECTOR /0-6 KM BULK SHEAR IN EXCESS OF 60 KT AND EFFECTIVE SRH OF 300-600 M2 PER S2/...WHERE 70-80 KT MID LEVEL FLOW OVERLAYS A 50-60 KT LLJ. THE PRIMARY CONCERNS IN THE WARM SECTOR WILL BE THE IMPACT OF DEBRIS CLOUDS AND RELATIVELY MODEST WARM SECTOR INSTABILITY. REGIONAL 12Z SOUNDINGS REVEALED RELATIVELY HIGH LFC/S AND STEEP LAPSE RATES LIMITED TO A SMALL PART OF THE MID TROPOSPHERE /600-450 MB/...WHILE CLOUDS ARE SLOWING SURFACE HEATING FROM E CENTRAL AR NWD. DESPITE MLCAPE VALUES OF ONLY 750-1500 J/KG...THE WEAKENING LOW-LEVEL FORCING SUGGESTS THAT THE THREAT FOR DISCRETE SUPERCELLS WILL INCREASE DURING THE AFTERNOON ALONG THE PRE-FRONTAL TROUGH. IT APPEARS THERE WILL BE A CORRIDOR WITH A SUPERCELL/TORNADO THREAT THIS AFTERNOON/EVENING ACROSS ERN AR/EXTREME NW MS/WRN TN...AND PERHAPS AS FAR N AS SE MO AND EXTREME WRN KY /DEPENDING ON L0W-LEVEL DESTABILIZATION/. ANY RELATIVELY LONG-LIVED SUPERCELLS COULD PRODUCE STRONG TORNADOES IN THIS MOIST/STRONGLY SHEARED ENVIRONMENT. THE SEVERE STORM THREAT SHOULD SPREAD NEWD LATE TODAY INTO TONIGHT TOWARD THE LOWER OH VALLEY AS THE WARM FRONT LIFTS NWD...THOUGH INSTABILITY WILL BE MORE LIMITED THAN AREAS TO THE SW THIS AFTERNOON. ALSO...STORMS SHOULD CONTINUE OVERNIGHT ALONG THE SLOW-MOVING BOUNDARY ACROSS LA/MS. A COUPLE OF TORNADOES WILL BE POSSIBLE...ALONG WITH DAMAGING WINDS AND MARGINALLY SEVERE HAIL. ..THOMPSON/SMITH.. 04/10/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z