Day 4-8 Outlook
DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0255 AM CST SUN NOV 04 2012 VALID 071200Z - 121200Z ...DISCUSSION... A PATTERN SHIFT WILL BE OCCUR DURING THE D4-D6 PERIOD...TRANSITIONING FROM AN ERN TROUGH/WRN RIDGE TO A LARGE WRN TROUGH. COOL AND DRY AIR WILL MAINTAIN STABLE CONDITIONS FOR MOST OF THE COUNTRY THROUGH D5...WITH MORE ROBUST MOISTURE RETURN BEGINNING ON FRI/D6 ACROSS THE PLAINS WHEN THE WRN TROUGH BEGINS TO AMPLIFY. THE ECMWF AND GFS MODELS ARE IN GENERAL AGREEMENT WITH BRINGING THIS TROUGH INTO THE PLAINS ON SAT/D7...BUT THE ECMWF IS A BIT FARTHER N WITH THE MAIN TROUGH ENERGY. REGARDLESS...BOTH MODELS INDICATE SOME THREAT OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CNTRL PLAINS WITH THE GREATEST LIKELIHOOD FROM KS INTO IA. LOW LEVEL MOISTURE QUALITY IS IN QUESTION...WITH DEWPOINTS IN THE UPPER 50S F THE MOST LIKELY SCENARIO PRODUCING MARGINAL INSTABILITY. HOWEVER...SHEAR WILL BE QUITE FAVORABLE FOR SEVERE THUNDERSTORMS. THE MARGINAL INSTABILITY WILL BE THE MAIN MITIGATING FACTOR. BY SUN/D8...THE COLD FRONT WILL BECOME MORE ESTABLISHED...WITH STORMS MORE NUMEROUS ALONG IT. HOWEVER...INSTABILITY WILL BE EVEN WEAKER THAN ON THE PREVIOUS DAY...AND ORIENTATION OF THE FRONT SUGGESTS A LINEAR MODE.
via SPC Forecast Products http://www.spc.noaa.gov/products/exper/day4-8/
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