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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 080550 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1250 AM CDT WED MAY 08 2013 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SERN CO/KS/WRN OK/NWRN TX... ...SYNOPSIS... WHILE THE ERN U.S. UPPER LOW IS PROGGED TO REMAIN INTACT AS IT MOVES NNEWD ACROSS THE MID-ATLANTIC REGION...THE WRN LOW IS FORECAST TO BECOME LESS ORGANIZED/MORE ELONGATED WITH TIME -- DEVOLVING INTO SEVERAL SMALLER-SCALE VORTICITY MAXIMA STRETCHING FROM THE SWRN U.S. ENEWD INTO THE PLAINS THROUGH THE SECOND HALF OF THE PERIOD. AT THE SURFACE...WEAK/DIFFUSE LOW PRESSURE IS FORECAST ACROSS THE UPPER OH VALLEY/MID-ATLANTIC REGION IN ASSOCIATION WITH THE ERN UPPER LOW. FARTHER W...A MORE WELL-DEFINED LOW IS FORECAST TO LINGER INVOF THE TX/OK PANHANDLES/WRN OK/SWRN KS VICINITY THROUGH THE AFTERNOON/EVENING...AS THE WRN UPPER SYSTEM NUDGES EWD. A WARM FRONT STRETCHING ENEWD FROM THIS LOW ACROSS KS AND A DRYLINE EXTENDING SWD ACROSS WRN OK/WRN N TX WILL BE A FOCUS FOR STRONG/SEVERE STORM DEVELOPMENT DURING THE AFTERNOON AND EVENING HOURS. ...SERN CO/KS/OK/NW TX... PERSISTENT SLY/SSELY LOW-LEVEL FLOW ACROSS THE SRN PLAINS ON THE WRN FRINGE OF AN ERN GULF HIGH AND AHEAD OF THE TX/OK PANHANDLE LOW WILL RESULT IN CONTINUED RETURN OF A PARTIALLY MODIFIED GULF AIRMASS. WITH 50S TO NEAR 60 SURFACE DEWPOINTS ARRIVING TO THE PROXIMITY OF THE SURFACE LOW/DRYLINE...EXPECT DEVELOPMENT OF 1500 TO 2500 J/KG MIXED-LAYER CAPE AS DIURNAL HEATING MAXIMIZES DURING THE LATE AFTERNOON HOURS. EXPECT CONVECTIVE INITIATION TO OCCUR NEAR THE SURFACE LOW/ALONG THE DRYLINE...AS WELL AS ACROSS SERN CO IN AN ELY/UPSLOPE FLOW REGIME N OF THE LOW. AIDED BY MODERATE INSTABILITY...EXPECT STORMS TO ORGANIZE...AS MODEST /25 TO 35 KT/ WLY MID-LEVEL FLOW SPREADS ATOP BOUNDARY LAYER SLYS/SELYS RESULTING IN SHEAR SUPPORTIVE OF SUPERCELLS. ATTM...LARGE HAIL APPEARS LIKELY TO BE THE PRIMARY SEVERE THREAT...AS FAIRLY LARGE SURFACE DEWPOINT DEPRESSIONS /IN EXCESS OF 20 DEGREES F IN MOST AREAS/ AND RELATIVELY WEAK LOW-LEVEL SHEAR IS ANTICIPATED. THE GREATEST TORNADO THREAT SHOULD EXIST FROM THE VICINITY OF PANHANDLE LOW NEWD INTO CENTRAL KS ALONG THE WARM FRONT. LOCALLY DAMAGING WINDS WILL ALSO BE POSSIBLE...AND MAY LINGER INTO THE EVENING AS HIGH-RES CONVECTION-ALLOWING MODELS HINT AT CLUSTERING OF STORMS INTO THE EVENING HOURS. THREAT SHOULD THEN DIMINISH LATER IN THE EVENING WITH THE ONSET OF DIURNAL COOLING. ...PARTS OF NC AND ERN VA... WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE ERN U.S. SURROUNDING THE UPPER LOW...AS IT DRIFTS NNEWD ACROSS THE MID-ATLANTIC REGION. WITH SLIGHTLY STRONGER FLOW AT MID LEVELS FORECAST AROUND THE SRN/ERN SIDE OF THE SYSTEM...POTENTIAL FOR SOMEWHAT MORE ORGANIZED CONVECTION WOULD APPEAR POSSIBLE ACROSS PARTS OF NC/VA AND VICINITY. HOWEVER...WITH RELATIVELY WEAK LAPSE RATES ANTICIPATED -- CONTRIBUTING TO MODEST AFTERNOON DESTABILIZATION AT BEST...ANY SEVERE THREAT SHOULD LIKEWISE REMAIN LIMITED. ATTM...WILL INCLUDE AN AREA OF 5% WIND PROBABILITY...AS SOME HINTS THAT STORMS MAY LOOSELY ORGANIZE INTO BANDS DURING THE AFTERNOON AS THEY SPREAD EWD ACROSS NC AND VA. ..GOSS.. 05/08/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |