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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 231952 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0252 PM CDT FRI AUG 23 2013 VALID 232000Z - 241200Z ...NO SVR TSTM AREAS FORECAST... NO CHANGES ARE MADE TO THE OUTLOOK FOR THIS ISSUANCE. ..BROYLES.. 08/23/2013 .PREV DISCUSSION... /ISSUED 1119 AM CDT FRI AUG 23 2013/ ...SYNOPSIS... THE DOMINANT WEATHER FEATURE IS A MID-UPPER LEVEL HIGH OVER THE CENTRAL STATES...WITH AN UPSTREAM TROUGH OVER THE PAC NW...AND A DOWNSTREAM TROUGH OVER THE UPPER OH VALLEY AND CENTRAL APPALACHIANS. THE APPALACHIANS WAVE WILL PROGRESS ESEWD TO THE MID ATLANTIC COAST BY TONIGHT AS AN ASSOCIATED SURFACE COLD FRONT MOVES SWD ACROSS THE OH VALLEY AND MID ATLANTIC STATES. MEANWHILE...THE MONSOONAL MOISTURE PLUME WILL PERSIST FROM NW MEXICO TO THE ERN GREAT BASIN. CONVECTION WILL BE MORE CONCENTRATED TODAY ACROSS CENTRAL UT...IN ADVANCE OF A WELL-DEFINED MCV MOVING NNEWD FROM NW AZ TO SW UT THIS MORNING. ...SE VA TO CENTRAL NC THIS AFTERNOON... A BAND OF LOW-MIDLEVEL ASCENT AND ASSOCIATED CLOUDS/RAINFALL WILL CONTINUE TO SPREAD ESEWD THIS AFTERNOON ACROSS VA...IN ADVANCE OF THE MIDLEVEL TROUGH OVER WV. IMMEDIATELY SE OF THE THICKER CLOUDS AND INVOF A DIFFUSE PRE-FRONTAL TROUGH...STRONGER SURFACE HEATING WILL BOOST MLCAPE VALUES TO 1000-2000 J/KG...DESPITE POOR MIDLEVEL LAPSE RATES SHOWN IN REGIONAL 12Z SOUNDINGS. THE MODERATE BUOYANCY AND SOMEWHAT STRONGER DEEP-LAYER VERTICAL SHEAR ACROSS SE VA WILL SUPPORT A RISK FOR ORGANIZED STORMS/CLUSTERS CAPABLE OF PRODUCING ISOLATED STRONG DOWNBURST WINDS THIS AFTERNOON. HOWEVER...WIDESPREAD AND/OR INTENSE SEVERE STORMS ARE NOT ANTICIPATED. ...SW INTO CENTRAL MT AREA THIS AFTERNOON... A WEAKENING SHORTWAVE TROUGH OVER THE ID PANHANDLE WILL PROGRESS NEWD TODAY OVER NW MT...THEN ENEWD OVER SRN AB/SK OVERNIGHT ON THE NWRN PERIPHERY OF THE CENTRAL US RIDGE. LOW-LEVEL MOISTURE AND BUOYANCY WILL REMAIN RATHER MODEST ACROSS CENTRAL/WRN MT TODAY...BUT DAYTIME HEATING WILL RESULT IN A DEEP BOUNDARY LAYER AND STEEP LOW-LEVEL LAPSE RATES. THE NET RESULT SHOULD BE AN ENVIRONMENT SUPPORTIVE OF THUNDERSTORM DEVELOPMENT THIS AFTERNOON OVER THE HIGHER TERRAIN OF W/SW MT...AND THE HIGH-BASED STORMS WILL THEN SPREAD NEWD TOWARD CENTRAL MT BY THIS EVENING. GIVEN A MODEST INCREASE IN MIDLEVEL SWLY FLOW AND INVERTED-V THERMODYNAMIC PROFILES...ISOLATED STRONG/DAMAGING GUSTS WILL BE POSSIBLE. ...WRN ND THIS AFTERNOON... LEE CYCLOGENESIS WILL CONTINUE ACROSS ERN MT...ALLOWING AN AIR MASS WITH 60S DEWPOINTS TO SPREAD NWD ACROSS THE DAKOTAS IN CONJUNCTION WITH THE NWD PROGRESS OF A SURFACE WARM FRONT. A FEW STRONG STORMS COULD OCCUR ACROSS WRN/CENTRAL ND WITHIN THE MOISTENING WAA REGIME...BUT ONLY LOW WIND/HAIL PROBABILITIES ARE WARRANTED GIVEN MODEST VERTICAL SHEAR AND UNCERTAINTY REGARDING STORM COVERAGE. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |
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