ZCZC SPCSWODY1 ALL ACUS01 KWNS 200601 SPC AC 200558 STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 201200Z - 211200Z THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS SC...CENTRAL/SRN GA AND SERN NC...TO THE RIGHT OF A LINE FROM 25 SSE SAV AYS MGR ABY 25 ENE CSG AHN 40 SE SPA SOP 25 SW GSB 35 SE OAJ. THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE TO THE RIGHT OF A LINE FROM VRB ORL GNV 15 NNW CTY 45 WNW CTY ...CONT... 15 ESE PNS MGM GAD BWG OWB MVN 35 SSW SPI PIA MMO SBN TOL CAK 20 W HLG PKB HTS 50 SSE JKL HSS 35 NE AVL 40 S ROA 55 WSW RIC 20 E ORF. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SW PNS 0A8 50 N MSL DYR 60 NE LIT FYV MKC OTM MSN MBL 10 ENE APN ...CONT... 40 N BML PSM. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 55 NW 4HV MLD 55 S COD 40 S CPR LAR LVS 4CR 30 N ALM 80 WNW TCS GUP 55 SW PUC. --- SYNOPSIS --- DEEP-TROPOSPHERIC CYCLONE NOW OVER CENTRAL CONUS IS EXPECTED TO EJECT NEWD ACROSS IL/INDIANA AND WEAKEN AS NRN STREAM MID-UPPER LEVEL CYCLONE NOW OVER SERN SASK DIGS SEWD INTO LONGWAVE TROUGH POSITION. SHORTWAVE PERTURBATION NOW OVER NERN MEX SHOULD EJECT NEWD ACROSS NRN GULF EARLY IN PERIOD AND OVER SRN APPALACHIANS/ PIEDMONT REGION THIS EVENING AND TONIGHT. THROUGHOUT PERIOD...MID- UPPER LEVEL JET MAX -- WITH 120-140 KT 300 MB FLOW AND 50-75 KT 500 MB WINDS -- SHOULD SHIFT SLOWLY EWD ACROSS AL/GA/CAROLINAS. WARM FRONT CURRENTLY EVIDENT ACROSS CENTRAL GA AND EXTREME SRN SC IS EXPECTED TO LIFT NWD AND INLAND INTO PIEDMONT REGION. SURFACE DRYLINE NOW OVER AL SHOULD MOVE SLOWLY EWD ACROSS PORTIONS WRN/CENTRAL GA DURING DAY. --- SERN CONUS --- PRIND MAXIMUM SUPERCELL POTENTIAL AND GREATEST TORNADO PROBABILITIES ARE BE OVER PORTIONS GA/CAROLINAS...ALONG AND S OF WARM FRONT. LOW LEVEL ASCENT...S-R HODOGRAPH SIZE...S-R INFLOW...AND VORTICITY EACH SHOULD BE MAXIMIZED INVOF WARM FRONT THROUGHOUT PERIOD. MULTIPLE EPISODES OF SEVERE ARE POSSIBLE... INCLUDING AFTER DARK. FORECAST KINEMATIC PROFILES FAVOR STORM ROTATION WITH 60 KT 500 MB FLOW...100 KT FLOW NEAR ANVIL LEVEL...50-75 KT 0-6 KM SHEAR...AND 250-450 J/KG 0-3 KM SRH. NEARLY STRAIGHT-LINE HODOGRAPHS IN WARM SECTOR SUPPORT POTENTIAL FOR SPLITTING STORMS WITH DAMAGING HAIL. BOW ECHOES WITH WIND DAMAGE ARE ALSO POSSIBLE AHEAD OF DRYLINE. MODIFIED ETA SOUNDINGS SHOW STEEPENED LOW-MIDLEVEL LAPSE RATES ASSOCIATED WITH COMBINATION OF DIURNAL HEATING AND OVERHEAD ADVECTION OF ELEVATED MIXED-LAYER AIR MASS NOW EVIDENT FROM TN VALLEY TO NRN GULF. MIDLEVEL ASCENT ASSOCIATED WITH SHORTWAVE TROUGH WILL CONTRIBUTE SOME DESTABILIZATION ALOFT AS WELL FROM AFTERNOON INTO LATE EVENING. AS SURFACE DEW POINTS RISE THROUGH 60S F...EXPECT MLCAPE 1500-2000 J/KG...PEAKING WITH DIABATIC HEATING IN AFTERNOON. --- OH VALLEY --- SCATTERED TO WIDELY SCATTERED TSTMS ARE POSSIBLE WITH LARGE HAIL...AND OCCASIONAL WIND DAMAGE POSSIBLE. MAIN THREAT WILL BE MORNING THROUGH LATE AFTERNOON. LARGE-SCALE ASCENT ASSOCIATED WITH EJECTING MID-UPPER LEVEL LOW WILL SPREAD ACROSS AREA EARLY IN PERIOD...STEEPENING MIDLEVEL LAPSE RATES ATOP FAVORABLE BOUNDARY LAYER MOISTURE. POCKETS OF DIABATIC HEATING WILL ENHANCE INSTABILITY WITH 1000-1500 J/KG MLCAPE POSSIBLE. ..EDWARDS.. 03/20/03 NNNN |