The SPC is forecasting ...severe thunderstorms expected over parts of the central plains this afternoon and tonight.... Please read the latest public statement about this event.
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SPC AC 221958 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0258 PM CDT THU MAY 22 2008 VALID 222000Z - 231200Z ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF WRN AND CNTRL KS... ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PART OF NE CO...WRN KS...CNTRL KS AND WRN OK... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS...CNTRL PLAINS AND CNTRL HIGH PLAINS... ...REGIONAL TORNADO OUTBREAK APPEARS LIKELY ACROSS NE CO...NWRN KS...WCNTRL KS AND NW OK THIS AFTERNOON AND EVENING... ...CNTRL AND SRN PLAINS/CNTRL HIGH PLAINS... A POWERFUL 90 TO 110 KT MID-LEVEL JET IS CURRENTLY ROUNDING THE BASE OF AN UPPER-LEVEL LOW OVER THE INTERMOUNTAIN WEST. THE EXIT REGION OF THE MID-LEVEL JET IS FORECAST TO EJECT NEWD ACROSS THE HIGH RISK AREA THIS EVENING. THIS COMBINED WITH A STRONG 50 TO 60 KT LOW-LEVEL JET WILL PROVIDE A SHEAR ENVIRONMENT FAVORABLE FOR SUPERCELLS AND TORNADOES SOME OF WHICH SHOULD BE STRONG. THE LATEST SFC ANALYSIS SHOWS A 984 MB LOW NEAR DENVER WITH A DRYLINE EXTENDING SEWD ACROSS NE CO INTO WRN KS. A WARM FRONT IS LOCATED NEAR GOODLAND AND EXTENDS SEWD INTO CNTRL KS. RUC DATA EAST OF THE DRYLINE SUGGESTS MODERATE TO STRONG INSTABILITY IS IN PLACE AND LOW-LEVEL CONVERGENCE HAS BECOME MORE FOCUSED OVER THE LAST HOUR. THIS ALONG WITH INCREASING LARGE-SCALE ASCENT AND STRONG VERTICAL SHEAR WILL ENCOURAGE RAPID SUPERCELL DEVELOPMENT ACROSS THE HIGH RISK AREA. REGIONAL PROFILERS HAVE IMPRESSIVE SHEAR PROFILES WITH 0-1 KM SHEAR VALUES OF 300 TO 400 M2/S2 SUGGESTING SUPERCELLS WILL BE CAPABLE OF PRODUCING STRONG TORNADOES. LOW-LEVEL SHEAR SHOULD BE ENHANCED NEAR THE WARM FRONT AND LONG-LIVED STRONG TORNADOES WILL BE MOST LIKELY ALONG THIS ZONE ESPECIALLY AS THE LOW-LEVEL JET STRENGTHENS LATE THIS AFTERNOON INTO THE EARLY EVENING. THE LATEST OBJECTIVE ANALYSIS ALSO SHOWS A PLUME OF VERY STEEP MID-LEVEL LAPSE RATES EXTENDING EWD ACROSS SW KS AND THIS SHOULD PROMOTE A THREAT FOR VERY LARGE HAIL WITH THE MORE INTENSE SUPERCELLS. FURTHER SOUTH ACROSS WRN OK...RUC DATA SUGGESTS STRONG INSTABILITY IS LOCATED EAST OF THE DRYLINE WITH MLCAPE VALUE INTO THE 2000 TO 2500 J/KG RANGE. AS VERTICAL SHEAR INCREASES ACROSS THE INSTABILITY AXIS AND A CAPPING INVERSION GRADUALLY WEAKENS...THE INSTABILITY AND THERMODYNAMIC ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS. SUPERCELLS SHOULD INITIATE AND MOVE ENEWD INTO ABUNDANT LOW-LEVEL MOISTURE AND INCREASING LOW-LEVEL SHEAR MAKING TORNADOES POSSIBLE WITH THE MORE DOMINANT CELLS. AN ISOLATED STRONG TORNADO MAY OCCUR ACROSS NWRN OK WHERE THE LOW-LEVEL JET IS EXPECTED TO BECOME MORE FOCUSED EARLY THIS EVENING. IN ADDITION...STEEP MID-LEVEL LAPSE RATES AND THE STRONG INSTABILITY SHOULD BE VERY FAVORABLE FOR LARGE HAIL. HAILSTONE OVER 2 INCHES WILL BE POSSIBLE WITH THE MORE INTENSE SUPERCELLS AS FAR SOUTH AS THE RED RIVER. ...LOWER MS VALLEY/ERN TX... A COMPLEX OF STRONG TO SEVERE THUNDERSTORMS IS CURRENTLY ONGOING IN FAR EAST TX...LA AND SW MS. THIS ACTIVITY HAS DEVELOPED AHEAD OF A SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY. ALTHOUGH REGIONAL FORECAST SOUNDINGS SUGGEST THE SHEAR ENVIRONMENT IS MARGINAL FOR ORGANIZED STORMS...THE STRONGER CELLS SHOULD HAVE THE POTENTIAL FOR STRONG GUSTY WINDS AND HAIL MAINLY DUE TO MODERATE INSTABILITY. ANY SEVERE THREAT SHOULD WEAKEN QUICKLY BY EARLY EVENING AS COOLING SFC TEMPS REDUCE INSTABILITY ACROSS THE REGION. ..BROYLES/KIS.. 05/22/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z