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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 161629 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1129 AM CDT THU MAY 16 2013 VALID 161630Z - 171200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER CENTRAL VA/SRN MD... ...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN TX INTO SRN AR AND NRN LA... ...CENTRAL VA/SRN MD... A PRE-FRONTAL BAND OF CONVECTION/ASSOCIATED CLOUDS EXTENDS FROM NRN/CENTRAL WV INTO NRN PARTS OF THE DELMARVA REGION. VISIBLE IMAGERY SHOWS GENERALLY CLEAR SKIES OVER CENTRAL VA AND SRN MD WHERE STRONG DIABATIC HEATING IS OCCURRING. SURFACE TEMPERATURES ARE EXPECTED TO WARM INTO THE MID/UPPER 80S THIS AFTERNOON AND WITH DEW POINTS IN THE LOW/MID 50S...A DEEP SURFACE-BASED MIXED LAYER /INVERTED-V SOUNDING STRUCTURE/ IS DEVELOPING. CONTINUED HEATING WILL GRADUALLY WEAKEN THE LIMITED CIN WITH ADDITIONAL THUNDERSTORMS EXPECTED TO DEVELOP EAST OF THE MOUNTAINS THIS AFTERNOON. UNIDIRECTIONAL WLY LOW/MID LEVEL WINDS OF 25-35 KT WILL CONTRIBUTE TO SUFFICIENT VERTICAL SHEAR FOR A FEW ORGANIZED STORM CLUSTERS TO FORM WITH STRONGER STORMS CAPABLE OF PRODUCING DAMAGING WIND GUSTS. THE THREAT IS EXPECTED TO DIMINISH BY THIS EVENING AS BOUNDARY LAYER COOLING/STABILIZATION COMMENCES. ...NERN TX/SRN AR/NRN LA... UPPER LOW OVER ERN OK IS FORECAST TO CONTINUE MOVING EWD INTO AR THROUGH TONIGHT AND PROVIDE A FOCUS FOR STRONG/SEVERE THUNDERSTORMS ALONG THE SRN PERIPHERY OF THE CIRCULATION. STORMS HAVE PERSISTED THIS MORNING NEAR THE RED RIVER WITHIN A LOW-LEVEL WARM ADVECTION ZONE ALONG/NORTH OF AN EARLIER OUTFLOW BOUNDARY. THIS ACTIVITY MAY ALSO BE ENHANCED BY A SMALL VORTICITY CENTER ROTATING CYCLONICALLY INTO THE SRN SEMI-CIRCLE OF THE UPPER LOW. VISIBLE IMAGERY SHOWS A CLEAR SLOT PROGRESSING EWD OVER ERN TX WHERE STRONGER DIABATIC HEATING WILL OCCUR...CONTRIBUTING TO DESTABILIZATION SPREADING INTO NWRN LA THIS AFTERNOON. STORMS ARE LIKELY TO INTENSIFY ALONG THE DIFFERENTIAL HEATING ZONE FROM NERN TX INTO SWRN AR/NWRN LA THIS AFTERNOON AND SPREAD EWD INTO THE EVENING HOURS. 35-45 KT WLY MID LEVEL WINDS WILL CONTRIBUTE TO SUFFICIENT DEEP LAYER SHEAR /40-50 KT IN THE LOWEST 6 KM/ TO ENHANCE STORM ORGANIZATION AND INTENSITY...WITH A THREAT FOR LARGE HAIL...DAMAGING WIND GUSTS...AND POSSIBLY SEVERAL TORNADOES. ...OH VALLEY INTO WV... LARGE-SCALE FORCING FOR ASCENT WILL REMAIN NEGLIGIBLE THIS AFTERNOON IN THE WAKE OF THE MIDLEVEL TROUGH MOVING INTO THE CANADIAN MARITIMES. THUS...IT APPEARS THAT LOW-LEVEL CONVERGENCE ALONG THE SURFACE FRONT WILL BE THE PRIMARY MECHANISM FORCING SURFACE-BASED TSTM DEVELOPMENT. POTENTIAL EXISTS FOR CORRIDORS OF STRONGER INSTABILITY WITH AFTERNOON MLCAPE APPROACHING 1000-1500 J/KG. HOWEVER...THE STRONGEST DEEP-LAYER WIND FIELD AND RESULTING VERTICAL SHEAR WILL REMAIN DISPLACED TO THE NORTH OF THE SURFACE FRONT. THIS WILL LIMIT THE POTENTIAL FOR AN ORGANIZED SEVERE WEATHER EPISODE...THOUGH ISOLATED OCCURRENCES OF DAMAGING WINDS AND/OR HAIL WILL BE POSSIBLE INTO THIS EVENING. ...HIGH PLAINS INTO MID-MO VALLEY... FORCING FOR ASCENT/DCVA ASSOCIATED WITH A SHORT-WAVE TROUGH EMERGING FROM THE CNTRL ROCKIES HAS CONTRIBUTED TO ELEVATED TSTMS MOVING ACROSS CENTRAL NEB WITHIN A MARGINALLY UNSTABLE THERMODYNAMIC ENVIRONMENT. EXPECT A GRADUAL INCREASE IN TSTM ACTIVITY AHEAD OF THIS FEATURE THIS AFTERNOON ALONG A NWD-MOVING SURFACE FRONT ACROSS SD/NEB...WITH ISOLATED TO WIDELY SCATTERED AFTERNOON TSTMS POSSIBLE WITHIN A WEAKER-FORCED ENVIRONMENT FROM THE VICINITY OF THE LEE LOW OVER WRN SD SWD ALONG THE LEE TROUGH/DRYLINE. THE COMBINATION OF MODERATELY STEEP MIDLEVEL LAPSE RATES...A MOISTENING BOUNDARY...AND DAYTIME HEATING WILL YIELD AFTERNOON MLCAPE APPROACHING 1000-1500 J/KG. WHEN COUPLED WITH MODEST /30-35 KT/ DEEP-LAYER SHEAR...THE POTENTIAL WILL EXIST FOR ISOLATED SEVERE STORMS CAPABLE OF HAIL AND DAMAGING WIND GUSTS. ..WEISS/COHEN.. 05/16/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z |