The SPC is forecasting ...severe thunderstorms expected over parts of the cntrl plains...srn plains and ozarks this afternoon and evening.... Please read the latest public statement about this event.
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SPC AC 091205 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0705 AM CDT THU APR 09 2009 VALID 091300Z - 101200Z ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER PARTS OF EASTERN OK...SOUTHEAST KS...SOUTHWEST MO...AND WESTERN AR... ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE SOUTHERN PLAINS INTO THE MID MS VALLEY... CURRENT WATER VAPOR LOOPS SHOW A POWERFUL AND PROGRESSIVE UPPER TROUGH OVER CO/NM. THIS FEATURE IS FORECAST TO TRACK EASTWARD INTO THE CENTRAL PLAINS TODAY WHILE DEEPENING AND BECOMING NEGATIVELY TILTED. MEANWHILE...A DEEP SURFACE LOW WILL MOVE ALONG THE KS/OK BORDER WITH A DRYLINE EXTENDING SOUTHWARD ACROSS OK INTO TX. THIS SHOULD SET THE STAGE FOR A FOCUSED BUT ACTIVE SEVERE WEATHER EVENT THIS AFTERNOON AND EVENING. ...SOUTHERN KS/NORTHERN OK THIS AFTERNOON... RAPID MOISTENING OF THE BOUNDARY LAYER IS OCCURRING THIS MORNING AS STRONG SOUTHERLY LOW LEVEL JET TRANSPORTS GULF AIRMASS NORTHWARD INTO OK/AR. BY MID AFTERNOON...SURFACE DEWPOINTS IN THE MID TO UPPER 50S ARE EXPECTED OVER MOST OF EASTERN OK EAST OF THE DRYLINE...WITH NEAR 50F DEWPOINTS WRAPPING WESTWARD ALONG THE KS/OK BORDER NEAR THE SURFACE LOW. THE CAPPING INVERSION WILL SUPPRESS SURFACE-BASED CONVECTION OVER THIS REGION THROUGH THE MORNING HOURS. HOWEVER...IT APPEARS LIKELY THAT STRONG FORCING AND COOLING ALOFT WILL YIELD A NARROW ZONE OF WEAKENING CAP ALONG THE OK/KS BORDER BY 19-21Z. ISOLATED THUNDERSTORMS WILL LIKELY DEVELOP IN THIS ZONE AND TRACK NORTHEASTWARD INTO SOUTHERN KS. FORECAST SOUNDINGS IN THIS REGION SUGGEST THE RISK OF RELATIVELY LOW-TOPPED SUPERCELLS CAPABLE OF HAIL AND ISOLATED TORNADOES. ...SOUTHEAST KS/EASTERN OK/SOUTHWEST MO/WESTERN AR... LATER THIS AFTERNOON...INCREASING LARGE SCALE FORCING OVER THE WARM SECTOR WILL ERODE THE MID LEVEL CAP AND LEAD TO ISOLATED SUPERCELL THUNDERSTORMS ALONG THE DRYLINE OVER EASTERN OK. THESE STORMS WILL MOVE INTO EXTREME SOUTHEAST KS...SOUTHWEST MO...AND WESTERN AR DURING THE EVENING. STEEP MID LEVEL LAPSE RATES AND COOL TEMPERATURES ALOFT...COUPLED WITH SUFFICIENT EFFECTIVE SHEAR FOR SUPERCELLS WILL PROMOTE THE RISK OF VERY LARGE HAIL IN STRONGER CELLS. FORECAST SOUNDINGS ALSO INDICATE SUBSTANTIAL VEERING AND INCREASING LOW LEVEL WINDS WITH HEIGHT...POSING A RISK OF SIGNIFICANT TORNADOES OVER THE MODERATE RISK AREA THROUGH EARLY EVENING. SURFACE DEWPOINT VALUES ARE ONLY FORECAST TO REACH THE LOWER 60S AT BEST ACROSS THE MDT AREA...BUT RAPIDLY COOLING TEMPERATURES ALOFT AND STRENGTH OF VERTICAL SHEAR GIVE SUFFICIENT CONFIDENCE TO UPGRADE REGION AT THIS TIME. OVERNIGHT...THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE AS THEY SPREAD EASTWARD ACROSS AR AND SOUTHERN MO INTO WESTERN KY/TN. THE SEVERE THREAT WILL LIKELY BECOME LESS ORGANIZED...BUT STRONGER CELLS WILL REMAIN CAPABLE OF HAIL AND DAMAGING WINDS MUCH OF THE NIGHT. ..HART/HURLBUT.. 04/09/2009 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z