The SPC is forecasting ...severe thunderstorms expected over parts of the midwestern states later today and tonight.... Please read the latest public statement about this event.
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SPC AC 301954 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0254 PM CDT FRI MAY 30 2008 VALID 302000Z - 311200Z ...THERE IS A MDT RISK OF SVR TSTMS LATE THIS AFTN INTO MID EVENING ACROSS PARTS OF E CNTRL MO...CNTRL IL INTO NRN/CNTRL IND.... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA ACROSS PARTS OF THE ERN PLAINS INTO THE OHIO VALLEY/LOWER GREAT LAKES REGION.... ...LWR MO VALLEY INTO LWR GREAT LAKES... REMNANT CLOUD COVER/PRECIPITATION ASSOCIATED WITH DISSIPATING CONVECTIVE CLUSTERS HAVE SLOWED/INHIBITED DESTABILIZATION ACROSS MUCH OF LOWER MICHIGAN AND THE LOWER GREAT LAKES...AS WELL AS FARTHER UPSTREAM ACROSS PARTS OF NORTHEAST MISSOURI INTO NORTHERN ILLINOIS/INDIANA. HOWEVER...HEATING OF THE MOIST BOUNDARY LAYER ALONG AND AHEAD OF AN ASSOCIATED CONVECTIVELY GENERATED SURFACE BOUNDARY...STRETCHING FROM NEAR A WARM FRONT OVER SOUTHERN LOWER MICHIGAN INTO THE LOWER MISSOURI VALLEY...IS GRADUALLY INCREASING INSTABILITY. AND...RUC GUIDANCE SUGGESTS THAT MIXED LAYER CAPE COULD STILL REACH 1500-3000 J/KG ACROSS NORTHERN INDIANA AND CENTRAL ILLINOIS INTO EAST CENTRAL MISSOURI LATE THIS AFTERNOON. THIS IS WHERE STRONGER HEIGHT FALLS ARE PROGGED BETWEEN NOW AND 31/00-02Z...ASSOCIATED WITH A BROAD UPPER TROUGH PROGRESSING EAST OF THE UPPER MISSISSIPPI VALLEY. LOW AMPLITUDE RIDGING IS ALREADY BECOMING INCREASINGLY EVIDENT IN WATER VAPOR IMAGERY OVER THE FOUR CORNERS REGION. AND...THE DOWNSTREAM TROUGH SHOULD BEGIN TO TURN SOUTHEASTWARD TOWARD THE GREAT LAKE LAKES REGION. SO...WITH INCREASING LARGE-SCALE FORCING AND DESTABILIZATION... INCREASING/INTENSIFYING CONVECTIVE DEVELOPMENT IS ANTICIPATED LATE THIS AFTERNOON ACROSS THE MODERATE RISK AREA. IN THE PRESENCE OF STRONG DEEP LAYER SHEAR ON THE SOUTHERN FRINGE OF A 60+ KT 500 MB JET STREAK NOSING THROUGH THE MIDDLE MISSISSIPPI VALLEY INTO LOWER GREAT LAKES REGION...THE DEVELOPMENT OF A QUASI-LINEAR CONVECTIVE SYSTEM STILL SEEMS PROBABLE. IN INITIAL...MORE DISCRETE ACTIVITY ...LOW-LEVEL SHEAR ALONG A 40 KT SOUTHWESTERLY 850 JET MAY STILL BE SUFFICIENT FOR THE RISK FOR TORNADOES...IN ADDITION TO LARGE HAIL. BUT...DAMAGING WIND GUSTS ARE EXPECTED TO BECOME THE MORE PROMINENT THREAT BY EARLY EVENING...POSSIBLY CONTINUING INTO LATE EVENING...BEFORE ACTIVITY WEAKENS AS IT SPREADS EASTWARD/ SOUTHEASTWARD THROUGH THE OHIO VALLEY. ...ERN DAKOTAS AND MID MO VALLEY INTO UPPER GREAT LAKES REGION... IN THE WAKE OF A PRE-FRONTAL WIND SHIFT EXTENDING FROM NEAR AN INTERSECTION WITH THE CONVECTIVE BOUNDARY OVER WEST CENTRAL MISSOURI...WEST SOUTHWESTWARD INTO THE TEXAS PANHANDLE...THE BOUNDARY LAYER REMAINS MOIST NEAR/EAST OF THE MIDDLE MISSISSIPPI VALLEY INTO THE UPPER GREAT LAKES. AND...WITH HEATING...THE ENVIRONMENT HAS BECOME WEAK TO MODERATELY UNSTABLE. AHEAD OF A COMPACT MID-LEVEL CIRCULATION...NOW DIGGING SOUTHEAST OF THE EASTERN DAKOTAS INTO THE BASE OF THE BROADER SCALE TROUGH... SCATTERED STRONG STORMS HAVE ALREADY INITIATED. SOME OF THIS ACTIVITY MAY BECOME CAPABLE OF PRODUCING LARGE HAIL/GUSTY WINDS AS IT SPREADS TOWARD IOWA/SOUTHERN WISCONSIN...BEFORE DIMINISHING THIS EVENING. ...SOUTH CENTRAL PLAINS... ISOLATED TO WIDELY SCATTERED STRONG/SEVERE STORMS ARE POSSIBLE IN THE PRESENCE OF MODERATE INSTABILITY AND MODERATE TO STRONG DEEP LAYER SHEAR ALONG PRE-FRONTAL WIND SHIFT ACROSS SOUTHEAST KANSAS INTO THE KANSAS/OKLAHOMA BORDER AREA. HOWEVER...BETTER POTENTIAL FOR A MORE SUBSTANTIAL CONVECTIVE CLUSTER WILL AWAIT THE ONSET OF STRONGER LOWER/MID TROPOSPHERIC WARM ADVECTION ON THE NORTHEASTERN FRINGE OF THE BUILDING SUBTROPICAL RIDGE. THIS MAY NOT OCCUR UNTIL VERY LATE TONIGHT INTO SATURDAY. ..KERR.. 05/30/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z