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| Probabilistic Tornado Graphic | |||||||||
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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| Probabilistic Damaging Wind Graphic | |||||||||
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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| Probabilistic Large Hail Graphic | |||||||||
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 230552 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1252 AM CDT THU MAY 23 2013 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN HIGH PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NERN STATES... ...SYNOPSIS... BLOCKING UPPER PATTERN WILL PERSIST THURSDAY. UPPER LOW OVER THE MID-UPPER MS VALLEY WILL ADVANCE THROUGH THE OH VALLEY...WHILE ANOTHER TROUGH AMPLIFIES SWD INTO THE GREAT LAKES REGION. CLOSED UPPER LOW OVER THE WRN STATES WILL DRIFT ONLY SLOWLY EWD...WHILE AN UPPER RIDGE BUILDS ACROSS THE CNTRL STATES. AT THE SFC A COLD FRONT WILL MOVE THROUGH ERN PORTIONS OF THE OH VALLEY INTO THE ERN STATES. TRAILING PORTION OF THIS BOUNDARY WILL LIFT NWD THROUGH NRN TX AND OK...WHILE A DRYLINE BECOMES ESTABLISHED ACROSS WRN TX. ...SRN HIGH PLAINS... CURRENT INDICATIONS ARE THAT ELEVATED STORMS WILL DEVELOP EARLY THURSDAY ACROSS NWRN TX INTO SWRN AND CNTRL OK WHERE THE NOCTURNAL LLJ WILL AUGMENT WARM ADVECTION AND ISENTROPIC ASCENT NORTH OF THE RETREATING BOUNDARY. RICHER LOW LEVEL MOISTURE WITH 60S DEWPOINTS WILL ADVECT NWWD THROUGH THE SRN PLAINS WARM SECTOR BENEATH STEEP LAPSE RATES. STRONG DIABATIC WARMING IS LIKELY SOUTH OF ONGOING CONVECTION ACROSS NWRN AND WRN TX...WHICH ALONG WITH INCREASING LOW-LEVEL MOISTURE WILL RESULT IN 2500-3000 J/KG MLCAPE DURING THE AFTERNOON. STORMS ARE EXPECTED TO DEVELOP BY MID-LATE AFTERNOON IN VICINITY OF THE DRYLINE/FRONT INTERSECTION OVER NWRN TX...AS WELL AS SOME DISTANCE SWD INTO THE HIGH PLAINS. RIDGING ALOFT WITH MODEST UPPER FLOW WILL TEMPER OVERALL SHEAR MAGNITUDES...BUT 30-35 KT EFFECTIVE SHEAR AND STRONG INSTABILITY WILL BE SUFFICIENT FOR A FEW SUPERCELLS WITH INITIAL STORMS THAT DEVELOP. PRIMARY THREAT WILL BE VERY LARGE HAIL. A TORNADO OR TWO MAY ALSO BE POSSIBLE ESPECIALLY DURING THE EARLY EVENING WHILE STORMS MAY STILL BE DISCRETE AND AS THE LLJ INCREASES. STORMS MAY EVOLVE INTO AN MCS AND PROPAGATE SEWD DURING THE EVENING WITH DAMAGING WIND BECOMING THE PRIMARY THREAT...BEFORE ACTIVITY WEAKENS TOWARD MID-LATE EVENING. ...NERN STATES... WIDESPREAD MULTILAYER CLOUDS ALONG CONVEYOR BELT WILL LIKELY LIMIT DIABATIC WARMING AND OVERALL DESTABILIZATION POTENTIAL ACROSS MUCH OF THE NERN STATES ON THURSDAY. HOWEVER...SOME CLOUD BREAKS WILL LIKELY OCCUR AND MODEST DIABATIC WARMING OF THE MOIST BOUNDARY LAYER WILL RESULT IN 500-1000 J/KG MLCAPE. BELT OF 35-40 KT MID-UPPER LEVEL FLOW ALONG ERN PERIPHERY OF THE UPPER TROUGH WILL EXIST IN WARM SECTOR RESULTING IN 30-40 KT EFFECTIVE SHEAR. STORMS MAY UNDERGO A GRADUAL INTENSIFICATION WITH ORGANIZED MULTICELLS CAPABLE OF PRODUCING MAINLY ISOLATED DAMAGING WIND. ANY SEVERE THREAT SHOULD DIMINISH BY EARLY EVENING. ..DIAL/GUYER.. 05/23/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |