ZCZC SPCSWODY1 ALL ACUS01 KWNS 280046 SPC AC 280044 STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 280100Z - 281200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 WNW LIT PGO MLC 25 NNW JLN 20 E MKC 20 ESE P35 BRL 15 WSW PIA BLV ARG 30 WNW LIT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 N PIE 35 SE JAX. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM ERI UNI LUK EVV DYR ELD GGG ACT MWL TUL 10 N FLV VOK 45 NNW APN. ...FLORIDA... SEVERE THREAT HAS DIMINISHED SUBSTANTIALLY DURING THE PAST HOUR OR TWO. MOST VIGOROUS CONVECTIVE DEVELOPMENT HAS WEAKENED/SHIFTED OFF THE ATLANTIC COAST...WITH STRONGEST LOW-LEVEL CONVERGENCE. SMALL CLUSTER OF STORMS PERSISTS EAST OF TAMPA...NEAR MID-LEVEL CYCLONIC VORTICITY CENTER ASSOCIATED WITH SHORT WAVE TROUGH...WHICH WILL CONTINUE TO GRADUALLY MIGRATE ACROSS THE FLORIDA PENINSULA THIS EVENING. COOL TEMPERATURES ALOFT /REF TBW 28/00Z RAOB/ MAY SUPPORT ISOLATED HAIL THREAT WITH THIS ACTIVITY AS IT SPREADS NORTHEASTWARD ACROSS EAST CENTRAL FLORIDA. THUNDERSTORM ACTIVITY IS EXPECTED TO END ACROSS MUCH OF THE PENINSULA AS UPPER TROUGH AXIS SHIFTS OFFSHORE AFTER 28/06Z...BUT LOW-LEVEL WARM ADVECTION REGIME ALREADY DEVELOPING IN WAKE OF SYSTEM MAY SUPPORT CONVECTION THROUGH THE NIGHT ACROSS EXTREME SOUTHERN FLORIDA AND THE KEYS. ...S CNTRL PLAINS/MID MS VLY/GREAT LAKES... LONG WAVE TROUGH IS EXPECTED TO CONTINUE TO EVOLVE FROM THE INTERMOUNTAIN WEST INTO MISSISSIPPI OVERNIGHT. MID/HIGH-LEVEL JET STREAK IS ALREADY MIGRATING ACROSS THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY...WITH ANOTHER UPSTREAM JET STREAK BEGINNING TO PROGRESS OUT OF THE SOUTHERN ROCKIES INTO THE SOUTHERN HIGH PLAINS. STRONG MID/UPPER FORCING FOR UPWARD VERTICAL MOTION STILL IS EXPECTED TO SUPPORT INCREASING CONVECTIVE DEVELOPMENT BY THE MID EVENING HOURS...FROM PARTS OF NORTHEASTERN OKLAHOMA INTO WEST CENTRAL MISSOURI. ALTHOUGH NOT SAMPLED BY 28/00Z RAOBS... NARROW AXIS OF INSTABILITY APPEARS TO BE DEVELOPING NEAR LOW-LEVEL THERMAL RIDGE FROM NEAR TULSA OK INTO AREAS EAST OF KANSAS CITY MO...AND IS EXPECTED TO PROVIDE FOCUS FOR CONVECTIVE DEVELOPMENT BY THE 28/03-06Z TIME FRAME AS CAP IS BROKEN. POINT FORECAST SOUNDINGS SUGGEST CAPE OF 500 TO 1000 J/KG BY LATE EVENING...SUPPORTIVE OF VIGOROUS CONVECTION IN STRONGLY SHEAR ENVIRONMENT. HAIL MAY EXCEED SEVERE LIMITS IN STRONGEST INITIAL ACTIVITY...BUT POTENTIAL FOR DAMAGING WIND GUSTS WILL INCREASE OVERNIGHT AS BROKEN LINE EVOLVES/INTENSIFIES ACROSS SOUTHERN MISSOURI WITH A SOMEWHAT BETTER MOISTURE RETURN ALONG SOUTHERLY LOW-LEVEL JET AXIS. ..KERR.. 03/28/03 NNNN |