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| Probabilistic Graphic |
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| Probability of severe weather within 25 miles of a point. Hatched Area: 10% or greater probability of significant severe within 25 miles of a point. |
SPC AC 120734 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0234 AM CDT THU APR 12 2012 VALID 141200Z - 151200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS CENTRAL OK AND ERN KS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA AND EXTENDING ACROSS THE SRN/CENTRAL PLAINS INTO THE UPPER MS VALLEY... ...POTENTIAL EXISTS FOR A SIGNIFICANT OUTBREAK OF TORNADOES AND VERY LARGE HAIL ACROSS PARTS OF OK/KS INTO SERN NEB/NWRN MO/SWRN IA... ...SYNOPSIS... AN AMPLIFIED FLOW PATTERN WILL REMAIN ACROSS THE CONUS THROUGH D3/SAT...WITH A LARGE TROUGH IN THE WEST AND DOWNSTREAM RIDGE ACROSS THE ERN STATES. THIS WILL MAINTAIN A CORRIDOR OF STRONG SWLY MIDLEVEL WIND EXTENDING FROM AZ/NM THROUGH OK/KS INTO THE UPPER MS VALLEY TO GREAT LAKES REGION. A PACIFIC TROUGH DIGGING SEWD INTO THE LOWER CO RIVER VALLEY DURING D2/FRI WILL MOVE THROUGH THE BASE OF THE WRN LONGWAVE TROUGH DURING ON SAT...REACHING CO/NM BY 12Z SUNDAY. AN ATTENDANT 100 KT MIDLEVEL JET WILL EMERGE INTO THE SRN HIGH PLAINS TO KS SAT NIGHT...WITH 60-80 KT SWLY MIDLEVEL WINDS EXPECTED ACROSS MUCH OF THE SLIGHT AND MODERATE RISK AREAS THROUGH THE FORECAST PERIOD. AT THE SURFACE...A FRONT IS EXPECTED TO ADVANCE EWD FROM THE UPPER MIDWEST INTO THE GREAT LAKES...WHILE THE TRAILING PORTION OF THIS BOUNDARY MOVES SLOWLY SWD ACROSS NEB. A LEE CYCLONE IS FORECAST TO DEVELOP AND DEEPEN ACROSS ERN CO WITH A WARM FRONT EXTENDING EWD THROUGH SRN NEB TO SRN IA. THE WARM FRONT WILL SPREAD NEWD INTO THE UPPER MS VALLEY ON SAT. A DRY LINE WILL MOVE EWD SOME BY SAT AFTERNOON AND SHOULD EXTEND FROM FAR ERN NEB SSWWD THROUGH CENTRAL KS TO FAR WRN OK TO THE TX BIG BEND REGION BY LATE SAT AFTERNOON. ...SRN AND CENTRAL PLAINS... WEAK HEIGHT FALLS ARE EXPECTED ACROSS THE SRN/CENTRAL PLAINS THROUGH SAT AFTERNOON...WITH STRONGER FALLS FORECAST FOR SAT EVENING/OVERNIGHT AS THE PACIFIC TROUGH MOVES TOWARD THE SRN AND CENTRAL HIGH PLAINS. STRONG SLY LOW LEVEL WINDS WILL MAINTAIN MOISTURE ADVECTION E OF THE DRY LINE ON SAT WITH SURFACE DEWPOINTS IN THE MID 60S EXPECTED ACROSS MUCH OF OK AND REACHING CENTRAL/ERN KS BY SAT EVENING. THIS MOISTURE RETURN COUPLED WITH STEEP MIDLEVEL LAPSE RATES AND STRONG SURFACE HEATING /ESPECIALLY NEAR THE DRY LINE/ WILL RESULT IN MODERATE TO STRONG INSTABILITY /MLCAPE 2000-2500 J PER KG/ ACROSS THE MODERATE RISK AREA BY LATE AFTERNOON AND THE SURROUNDING SLIGHT RISK. STRENGTHENING DEEP LAYER WIND FIELDS...VEERING WITH HEIGHT...WILL RESULT IN STRONG EFFECTIVE BULK SHEAR /EXCEEDING 50 KT/ AND ORIENTED ACROSS THE DRY LINE. THIS COMBINED WITH INCREASING LOW LEVEL HODOGRAPH CURVATURE WILL SUPPORT TORNADIC SUPERCELLS AND THE POTENTIAL FOR VERY LARGE HAIL AND DAMAGING WINDS. THESE FACTORS COMBINED WITH FAST STORM MOTIONS SUGGEST THE POTENTIAL FOR LONG-TRACKED...STRONG TORNADOES OCCURRING FROM THE AFTERNOON THROUGH THE EVENING /INCLUDING AFTER DARK/. ...ERN NEB/IA/NRN MO/NWRN IL/SWRN-SRN WI... STRENGTHENING SWLY MIDLEVEL WINDS ACROSS THIS REGION THROUGH D3 COMBINED WITH MOISTURE/DESTABILIZATION OCCURRING AS A WARM FRONT ADVANCES NNEWD SUGGESTS THE ENVIRONMENT WILL BECOME INCREASINGLY FAVORABLE FOR STRONG TO SEVERE STORMS. MODELS SUGGEST SHORTWAVE RIDGING ACROSS THIS REGION. HOWEVER..A FEW WEAK IMPULSES EMBEDDED IN THE STRONGER FLOW ALOFT AND FORCING FOR ASCENT ALONG THE SWD MOVING FRONT AND INVOF OF THE WARM FRONT SHOULD SUPPORT DEEP MOIST CONVECTION/TSTMS. MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR OF 40-50 KT WILL FAVOR ORGANIZED STORMS WITH ALL FACETS OF SEVERE WEATHER POSSIBLE. GREATEST TORNADO THREAT SHOULD BE CONFINED TO THE WARM FRONT AND ALSO WWD NEAR THE INTERSECTION OF THE DRY LINE WARM FRONT...WHERE LOW LEVEL SHEAR WILL BE ENHANCED. ..PETERS.. 04/12/2012 CLICK TO GET WUUS03 PTSDY3 PRODUCT NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z