DAY 2 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWI47 KWNS.
VALID 211200Z - 221200Z
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
25 SW CRE 35 W CHS 45 WSW AGS 20 WSW AND 30 N HKY 40 SSW EKN
15 SSW PSB 25 SSW IPT 10 WSW ILG 25 E SBY.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM ELP 30 NW TCS
50 SW GUP 40 SSW DRA 20 W MER 45 NW RBL 50 NNE RDM 20 WNW GEG
55 NNE 3DU 45 NNE 81V 30 NE SNY 20 ENE EHA CDS 20 WSW MWL
25 NW LFK 15 N HEZ 35 S CBM 40 E HSV 45 SE LOZ 10 E UNI 30 NE CLE
...CONT... 40 N BML 20 SSE PVD ...CONT... 50 SSE JAX 55 SSE CTY.
...SYNOPSIS...
HIGHLY-AMPLIFIED MID-LEVEL FLOW IS FORECAST ACROSS THE CONUS THIS
PERIOD WITH A TROUGH OVER THE WEST...A RIDGE OVER THE ERN ROCKIES
AND PLAINS STATES...AND A TROUGH MOVING ACROSS THE ERN CONUS.
MAIN SURFACE FEATURE AFFECTING THE SEVERE CONVECTIVE FORECAST THIS
PERIOD WILL BE A SURFACE BOUNDARY WHICH IS FORECAST TO MOVE EWD
ACROSS THE APPALACHIANS. FURTHER SOUTH AND WEST...THIS BOUNDARY IS
FORECAST TO LINGER INVOF THE GULF COAST AND THEN EXTEND WWD ACROSS
SRN AND WRN TX INTO NM.
...MIDDLE AND SRN ATLANTIC COAST STATES...
STRONGER DEEP-LAYER WIND FIELD AND LARGE-SCALE ASCENT ASSOCIATED
WITH APPROACHING TROUGH IS FORECAST TO SPREAD SLOWLY EWD ACROSS THE
APPALACHIANS DURING THE PERIOD. WITH DEWPOINTS IN THE UPPER 50S
AND LOW 60S EXPECTED TO RETURN NWD ACROSS THIS REGION...DAYTIME
HEATING WILL ALLOW AIRMASS TO DESTABILIZE YIELDING 1000 TO 1500
J/KG SURFACE-BASED CAPE DURING THE AFTERNOON.
ALTHOUGH COLD FRONT IS FORECAST ATTM TO REMAIN W OF THE APPALACHIAN
FRONT THROUGH LATE AFTERNOON / EVENING...LEE-TROUGH MAY PROVIDE A
LOW-LEVEL FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT BY MID-
AFTERNOON FROM THE CAROLINAS NWD INTO PA / NY. ALTHOUGH NOT
EXCESSIVELY STRONG...DEEP-LAYER SHEAR WILL LIKELY BE SUFFICIENT FOR
STORM ORGANIZATION...WITH HAIL AND LOCALLY DAMAGING WINDS POSSIBLE
WITH MULTICELL STORM CLUSTERS OR PERHAPS SMALL-SCALE BOWS. MORE
ISOLATED / WEAKER CONVECTION MAY DEVELOP SWD ACROSS GA AND THE
CENTRAL GULF COAST REGION...BUT WEAKER WIND FIELD / LARGE SCALE UVV
SUGGESTS THAT ONLY A MARGINAL SEVERE THREAT WILL EXIST AT BEST.
...SERN NM / FAR W TX INTO THE TRANSPECOS / SOUTH PLAINS REGION...
ETA FORECASTS SUGGEST THAT MOISTURE WILL BEGIN TO RETURN INTO W TX
DURING THE DAY AS LOW-LEVEL SELY FLOW INCREASES AND OLD SURFACE
BOUNDARY RETURNS SLOWLY NWD AHEAD OF APPROACHING WRN U.S. TROUGH.
ALTHOUGH OPERATIONAL ETA DEVELOPS SUFFICIENT /AROUND 500 J/KG/
SURFACE-BASED INSTABILITY ACROSS FAR W TX DURING THE DAY...IT
APPEARS THAT SOME OF THE DESTABILIZATION IS DUE TO SHALLOW
CONVECTIVE SCHEME. LOCAL ETA KF RUN SUGGESTS THAT SURFACE-BASED
AIRMASS REMAINS TOO DRY / CAPPED TO SUPPORT CONVECTIVE DEVELOPMENT
DURING THE DAY.
DEEP-LAYER WIND FIELD WILL LIKELY BE FAVORABLE WITH LOW-LEVEL SELY
FLOW BENEATH INCREASING MID-LEVEL WSWLYS. IF SUFFICIENT LOW-LEVEL
MOISTURE CAN RETURN INTO W TX...SOME THREAT FOR AT LEAST HIGH-BASED
SUPERCELLS COULD EVOLVE. HOWEVER...MORE LIKELY SCENARIO WOULD BE
FOR SCATTERED ELEVATED STORM DEVELOPMENT AND A LIMITED THREAT FOR
HAIL ACROSS THE TRANSPECOS / SOUTH PLAINS REGION OVERNIGHT AS SELY
LOW-LEVEL JET DEVELOPS. IF LATER MODEL RUNS INDICATE SUFFICIENT
MOISTURE RETURN INTO THIS REGION...OUTLOOK MAY HAVE TO BE UPGRADED
TO SLIGHT RISK.
..GOSS.. 04/20/03
