SPC Day 1 Thunderstorm Outlook Issued 16Z 20030315


ZCZC SPCSWODY1 ALL
ACUS01 KWNS 151634
SPC AC 151631

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.

VALID 151630Z - 161200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
15 WSW PNS 25 NNW CEW 20 NNE MAI MGR 40 W JAX 35 NNW DAB.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
10 NE BFL 40 W BFL 25 SSW SCK 50 E UKI 55 SSE RBL 65 N SAC
50 SSW TVL 30 NE FAT 65 ESE FAT 10 NE BFL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SSE MOB 30 W TCL
MSL CSV TYS CLT FAY 25 SSE EWN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 NW BLI 25 E SEA
20 ESE ALW 65 SE S80 20 SW PIH 30 ESE U24 55 WSW PRC 70 ESE YUM.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 80 SSW P07 50 SW AMA
40 NNW LBL GRI 10 ESE SUX 35 S FOD 10 SSW LWD 35 E ICT 25 SE SPS
30 WNW ACT 20 W CLL 15 NNW HOU 20 S BPT.

...CA AREA...
A MID LEVEL TROUGH IS APPROACHING THE NRN CA COAST...AND WILL
CONTINUE INLAND OVER CENTRAL/NRN CA THROUGH THIS AFTERNOON.  WHILE
SOME CONVECTION WILL CONTINUE IN THE MAIN BAROCLINIC BAND ACROSS
CENTRAL CA THIS MORNING...IT APPEARS THE MAIN THREAT FOR STRONG/
ISOLATED SEVERE STORMS WILL BE THIS AFTERNOON IN THE CENTRAL
VALLEY.  THE MID LEVEL THERMAL TROUGH WILL MOVE OVER THIS AREA
DURING THE AFTERNOON WHEN TEMPERATURES SHOULD WARM INTO THE 60S
WITH DEW POINTS IN THE 50S...SUPPORTING SBCAPE VALUES OF 500-1000
J/KG AND THE POSSIBILITY OF LARGE HAIL.  FORECAST SOUNDINGS FROM
THE ETA-KF ALSO SUGGEST THAT LOW-LEVEL FLOW MAY REMAIN BACKED
THROUGH THE AFTERNOON IN THE SAN JOAQUIN VALLEY...THUS THERE MAY
ALSO BE SOME THREAT OF SUPERCELLS AND PERHAPS AN ISOLATED TORNADO.

...SE STATES...
CLOUDS WILL GRADUALLY ERODE OVER THE FL PENINSULA WITH DAYTIME
HEATING/MIXING...WHICH SHOULD ALLOW LOCAL SEA BREEZE CIRCULATIONS
TO BECOME ESTABLISHED BY LATER THIS AFTERNOON.  MODERATE
INSTABILITY...MODEST DEEP LAYER SHEAR...AND 500 MB TEMPERATURES OF
-12 C OVER S FL AND -14 C OVER THE FL PANHANDLE MAY SUPPORT A FEW
STORMS WITH LARGE HAIL AND POSSIBLY STRONG OUTFLOW GUSTS.  FARTHER
NE...THERE IS SOME THREAT THAT THE WARM SECTOR COULD REACH THE SC
COAST THIS AFTERNOON.  HOWEVER...GIVEN CURRENT CONVECTION OFFSHORE
AND COOL AIR DAMMING INLAND...WILL OUTLOOK ONLY LOW PROBABILITIES
OF HAIL/WIND NEAR THE COAST AT THIS TIME.

...TX/OK/KS AREA...
WATER VAPOR IMAGERY AND 12Z UPPER AIR ANALYSES CONFIRM THAT A N-S
TROUGH OVER THE HIGH PLAINS IS MOVING EWD...WITH SEVERAL EMBEDDED
VORTICITY CENTERS.  THE MOST PRONOUNCED VORTICITY CENTER IS MOVING
SEWD OVER MEXICO...AND WILL LIKELY REMAIN S OF THE RIO GRANDE...
WHILE ANOTHER VORT MAX IS MOVING E/ENEWD FROM ERN CO. 
THEREFORE...EXPECT AT BEST WEAK LARGE SCALE FORCING FOR ASCENT
ACROSS THE W TX AREA.  THROUGH MOISTURE IS SPREADING NWD ACROSS THE
SJT-ABI AREA...EXPECT THE DRYLINE TO BE RATHER DIFFUSE AS A RESULT
OF THE WEAK LARGER SCALE FLOW PATTERN AND THE CIRRUS OVER W TX THAT
WILL SLOW SURFACE HEATING SOME.  THERE WILL STILL BE SOME THREAT
FOR HAIL/STRONG DOWNDRAFTS GIVEN STEEP LAPSE RATES AND COOL MID
LEVEL TEMPERATURES...BUT ONLY LOW HAIL/WIND PROBABILITIES SEEM
JUSTIFIABLE.  FARTHER S...WIDESPREAD CLOUDS/PRECIPITATION WILL TEND
TO LIMIT DESTABILIZATION OVER S TX...THOUGH WILL MAINTAIN LOW
PROBABILITIES OF HAIL/WIND DAMAGE THIS AREA.  
 
..THOMPSON.. 03/15/03

NNNN