Post by SKYSUMMIT on Feb 25, 2009 10:09:27 GMT -6
| DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0320 AM CST WED FEB 25 2009 VALID 281200Z - 051200Z ...DISCUSSION... MODELS CONTINUE TO INDICATE AMPLIFIED TROUGH SHIFTING ACROSS THE EAST COAST THIS WEEKEND...PUNCTUATED BY STRONG IMPULSE DIGGING SEWD ACROSS THE SOUTHEASTERN STATES SATURDAY AND SUNDAY WITH ASSOCIATED 50+ KT MID LEVEL JET. PRECEEDING THIS IMPULSE...SURFACE FRONT IS EXPECTED TO STALL SOMEWHERE OVER THE DEEP SOUTH FRIDAY. ECMWF REMAINS FARTHER SOUTH WITH ITS POSITION OF STALLED SURFACE FRONT OVER THE CENTRAL GULF COAST STATES FRIDAY...WHILE THE GFS AND MREF-MEAN STALL THE FRONT FARTHER NORTH OVER THE SRN APPALACHIANS AND MID SOUTH. REGARDLESS...EXTENDED MODELS ARE CONSISTENT IN DEVELOPING A SURFACE LOW NEAR THE FRONT SATURDAY WHICH TRACKS EWD ACROSS PORTIONS OF GA/SC WITH TRAILING COLD FRONT ACCELERATING ESEWD ACROSS THE CENTRAL GULF COAST STATES AND INTO NRN FL BY SATURDAY NIGHT. INTENSE LOW LEVEL AND DEEP LAYER SHEAR...ALONG WITH -14C TO -16C H5 TEMPS...WILL LIKELY FAVOR SQUALL LINE DEVELOPMENT AND POSSIBLY SUPERCELLS SATURDAY INTO EARLY SUNDAY OVER THE SOUTHEASTERN STATES AS PRE-FRONTAL AIRMASS UNDERGOES MODEST DESTABILIZATION. AT LEAST AN ISOLATED SEVERE THREAT COULD PERSIST SWD ACROSS FL IN SOME FORM THROUGH SUNDAY MORNING...ATTENDANT TO SEWD MOVING SQUALL LINE...ALTHOUGH COVERAGE/MAGNITUDE OF THREAT REMAINS LESS CERTAIN ATTM. IN THE WAKE OF THIS SYSTEM...BEYOND DAY 5...MODELS IN GENERAL AGREEMENT IN DEVELOPING BROAD TROUGH OVER THE WRN STATES AND FAST/ZONAL FLOW ACROSS THE SERN 1/4 OF THE COUNTRY. IN ADDITION... PATTERN SHOULD FAVOR GULF MOISTURE RETURN OVER PORTIONS OF THE SRN PLAINS INTO THE LOWER/MID MS RIVER VALLEY BY THE END OF THE FORECAST PERIOD...UNDER STRENGTHENING WESTERLIES ALOFT. HOWEVER...FAR TOO MANY UNCERTAINTIES REMAIN ATTM TO ADDRESS ANY PARTICULAR SEVERE THREAT INTO EARLY NEXT WEEK. ..EVANS.. 02/25/2009 |
