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 040551 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1251 AM CDT FRI MAY 04 2007 VALID 041200Z - 051200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF NEB...ERN CO...MUCH OF KS...ERN TX PANHANDLE...WRN OK... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM SWRN TX INTO SD... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CENTRAL GULF STATES... ...POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT POSSIBLE TODAY ACROSS THE PLAINS... LARGE SCALE HEIGHT FALLS WILL SPREAD ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES/HIGH PLAINS TODAY AS UPPER LOW REDEVELOPS INTO THE 4-CORNERS REGION LATE. THIS LARGE SCALE EVOLUTION WILL ALLOW FOR RAPID BOUNDARY LAYER RECOVERY ACROSS THE PLAINS AS LEE CYCLOGENESIS DEVELOPS OVER SERN CO IN RESPONSE TO APPROACHING JET MAX. PARAMETERS APPEAR TO BE COMING TOGETHER FOR POTENTIALLY TORNADIC SUPERCELLS...ESPECIALLY ACROSS THE MODERATE RISK FROM SCNTRL NEB INTO THE ERN TX PANHANDLE/WRN OK. EARLY MORNING DIAGNOSTIC DATA INDICATES THE WARM SECTOR IS MOISTENING NICELY WITH SFC DEW POINTS AOA 60F ACROSS MUCH OF THE CNTRL PLAINS...WITH NEAR 70F INTO THE TX HILL COUNTRY. AS LOWER MS VALLEY UPPER TROUGH SHIFTS EAST LATER TODAY AND LLJ STRENGTHENS ACROSS THE HIGH PLAINS...NEAR 70F DEW POINTS SHOULD EASILY SPREAD INTO OK...WITH MID-UPPER 60S INTO THE DRYLINE OVER KS...NWD INTO SCNTRL NEB. GIVEN THIS MARKED INCREASE IN MOISTURE MDT-HIGH INSTABILITY WILL DEVELOP ACROSS THE ENTIRE WARM SECTOR BY LATE AFTERNOON. SBCAPE VALUES COULD EASILY EXCEED 4000 J/KG ACROSS MOST OF THE SRN PLAINS INTO PORTIONS OF KS...HIGHER THAN MODELS WOULD SUGGEST. ADDITIONALLY...STRONG SFC HEATING ALONG/WEST OF THE DRYLINE OVER THE TX SOUTH PLAINS INTO THE OK PANHANDLE WILL CERTAINLY REMOVE ANY INHIBITION ACROSS THIS REGION. IT SEEMS REASONABLE THAT SUPERCELLS SHOULD DEVELOP DURING THE 21-00Z TIME FRAME FROM SWRN KS...SWD INTO SWRN TX WHERE DEEP LAYER SHEAR WILL ONLY INCREASE AS UPPER TROUGH ADVANCES EWD. ANOTHER POTENTIALLY MORE CONCENTRATED ZONE FOR SUPERCELL DEVELOPMENT WILL OCCUR ACROSS PORTIONS OF ERN CO. THIS ACTIVITY SHOULD SPREAD/DEVELOP DOWNSTREAM INTO NEB/NRN KS WHERE DEEP ELY FLOW AND VERY PRONOUNCED LOW LEVEL TURNING WILL ENHANCE HELICITY FOR TORNADOES. AS LLJ STRENGTHENS DURING THE EVENING HOURS SCATTERED SUPERCELLS SHOULD BE MAINTAINED WITHIN HIGH QUALITY AIRMASS ACROSS THE PLAINS...WHILE LARGE SCALE FORCING/ASCENT GRADUALLY INCREASE AFTER DARK. ALTHOUGH DRYLINE SHOULD BE THE INITIAL INSTIGATOR FOR SUPERCELLS...ADDITIONAL DEVELOPMENT IS POSSIBLE DURING THE OVERNIGHT HOURS AS UPPER SPEED MAX EJECTS INTO THE CNTRL HIGH PLAINS. AT THAT TIME WIDESPREAD CONVECTION SHOULD EVOLVE WITHIN STRONG WARM ADVECTION REGIME ACROSS MUCH OF NEB/SD. VERY LARGE HAIL MAY ACCOMPANY HIGH INSTABILITY SUPERCELLS...ALONG WITH A FEW STRONG TORNADOES. ...CENTRAL GULF STATES... LOWER MS VALLEY UPPER TROUGH WILL GRADUALLY SHIFT EAST TODAY. THIS FEATURE HAS A HISTORY OF DIURNALLY ENHANCED CONVECTION THE PAST SEVERAL DAYS...WITH ACTIVITY BEING MAINTAINED INTO THE LATE EVENING HOURS. ONGOING CONVECTION ACROSS MS/LA SHOULD SPREAD DOWNSTREAM LATER THIS MORNING AND WEAKEN. BOUNDARY LAYER HEATING BENEATH THE UPPER LOW SHOULD ONCE AGAIN PROVE FAVORABLE FOR RENEWED DEVELOPMENT BY EARLY AFTERNOON...AT THE LATEST. LARGE HAIL AND STRONG WINDS MAY BE OBSERVED WITH STRONGER STORMS. ..DARROW/TAYLOR.. 05/04/2007 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z