DAY 1 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1228 AM CDT FRI AUG 23 2013 VALID 231200Z - 241200Z ...NO SVR TSTM AREAS FORECAST... CORRECTED OUTLOOK GRAPHIC ...SYNOPSIS... AN UPPER LOW OVER THE PACIFIC NW WILL WEAKEN DURING THE DAY AS IT MOVES INTO SRN ALBERTA BY THE EVENING AHEAD OF A LARGER-SCALE TROUGH MOVING TOWARDS VANCOUVER/BC. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN ENTRENCHED ACROSS THE S-CNTRL U.S. FARTHER EAST A MID-LEVEL DISTURBANCE...LOCATED WITHIN THE BASE OF A LARGER-SCALE ERN U.S. TROUGH...WILL MOVE FROM UPPER OH VALLEY/SRN APPALACHIANS ACROSS THE CAROLINAS DURING THE DAYTIME/EVENING HOURS. IN THE LOW LEVELS...A COLD FRONT WILL PUSH THROUGH THE CAROLINAS DURING THE AFTERNOON/EVENING PROVIDING A FOCUS FOR SHOWERS/THUNDERSTORMS. ...MT/ERN WY/WRN DAKOTAS/NEB PANHANDLE... SURFACE CYCLOGENESIS WILL OCCUR OVER ERN MT THROUGH THE AFTERNOON AS A SHORTWAVE TROUGH MOVES INTO THE SRN CANADIAN PRAIRIE PROVINCES TO THE N OF A MID LEVEL RIDGE CENTERED OVER OK. A LOW LEVEL MOIST AXIS FEATURING BOUNDARY LAYER DEWPOINTS IN THE UPPER 50S-LOWER 60S DEG F WILL PROTRUDE NWWD FROM THE MID MO VALLEY INTO ERN MT...AS A LEE TROUGH EXTENDS N-S OVER THE NRN-CNTRL HIGH PLAINS. STRONG SURFACE HEATING WILL PROBABLY LEAD TO WIDELY SCTD STORMS DEVELOPING OVER THE NRN ROCKIES AND THIS ACTIVITY SHOULD MOVE EWD INTO THE HIGH PLAINS DURING THE LATE AFTERNOON. FARTHER E/SE INVOF THE SURFACE LOW AND LEE TROUGH...ISOLD STORMS ARE EXPECTED TO DEVELOP DURING THE LATE AFTERNOON/EVENING HOURS. IN BOTH AFOREMENTIONED AREAS...THE PRESENCE OF STEEP LOW TO MID-LEVEL LAPSE RATES MAY FOSTER AN ISOLD LARGE HAIL/SEVERE WIND GUST THREAT WITH THE MORE VIGOROUS STORMS BEFORE THIS ACTIVITY WEAKENS DURING THE EVENING. ...SRN VA/CAROLINAS... FORCING FOR ASCENT ASSOCIATED WITH THE UPPER TROUGH AND THE FRONT WILL FAVOR THE EVENTUAL DEVELOPMENT OF SCTD STORMS DURING THE MIDDAY-EARLY EVENING HOURS. ALTHOUGH MID-LEVEL LAPSE RATES ARE FORECAST TO REMAIN MODEST...A MOISTURE RICH BOUNDARY LAYER --CHARACTERIZED BY UPPER 60S TO LOWER 70S DEWPOINTS-- WILL CONTRIBUTE TO MODERATE INSTABILITY. STRONG TO LOCALLY SEVERE MULTICELLULAR STORM CLUSTERS MAY YIELD ISOLD POCKETS OF WIND DAMAGE AND PERHAPS MARGINALLY SEVERE HAIL BEFORE WEAKENING DURING THE EVENING.
Posted on: Fri, 23 Aug 2013 11:10:22 +0000
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