[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 031726
SWODY2
SPC AC 031724

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1124 AM CST WED JAN 03 2007

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SE TX TO EXTREME SERN
MS....

...SYNOPSIS...
PRONOUNCED MID/UPPER LEVEL CYCLONE IS EVIDENT IN MOISTURE CHANNEL
IMAGERY OVER NWRN MEX.  THIS SYSTEM IS EXPECTED TO EJECT ENEWD THEN
EWD ACROSS WRN/CENTRAL TX...REACHING E TX OR VICINITY TX/LA BORDER
AROUND 4/12Z BASED ON LATEST OPERATIONAL SPECTRAL/ETA FCST...AS WELL
AS CONSENSUS OF 3/09Z ENSEMBLE RUNS.  THIS WILL BE FOLLOWED BY
HEIGHT FALLS ACROSS MUCH OF WRN CONUS...AS
HIGH-AMPLITUDE/POSITIVELY-TILTED TROUGH EVOLVES FROM PERTURBATIONS
NOW OVER N-CENTRAL PACIFIC.

LOW LEVEL FRONTAL ZONE IS EVIDENT ATTM OVER CENTRAL/NRN GULF...WITH
SFC BOUNDARY ROUGHLY LOCATED FROM VERACRUZ NWD TO ABOUT 100 NM SE
BRO...THEN EWD TOWARD BUOY 42003...THEN ACROSS S-CENTRAL FL.  AS MEX
UPPER LOW APCHS...FRONTAL-WAVE LOW IS EXPECTED TO DEVELOP ALONG
INFLECTION POINT OF SFC FRONTAL ZONE...OVER NWRN GULF.  THIS LOW
SHOULD MOVE NEWD ACROSS NWRN GULF AND ONSHORE BPT-LCH VICINITY EARLY
IN PERIOD...HOWEVER POSITIONING/STRENGTH OF LOW WILL DEPEND STRONGLY
ON MESOSCALE FACTORS INCLUDING PRECIP-RELATED MODULATION OF FRONTAL
ZONE IN W GULF AREA.  STRONGEST ASSOCIATED PRESSURE FALLS SHOULD
MOVE NEWD INTO PROGRESSIVELY COLDER AND MORE STABLE AIR...LEAVING
WAVY SFC FRONTAL ZONE LOCATED ACROSS SERN LA LATE IN PERIOD.

...W GULF COASTAL PLAIN TO MS DELTA...
SCATTERED-NUMEROUS TSTMS ARE POSSIBLE THROUGHOUT PERIOD...SHIFTING
GENERALLY EWD ACROSS REGION.  ACTIVITY WILL OCCUR IN ENVIRONMENT OF
STRONG VERTICAL SHEAR SUPPORTING SUPERCELLULAR MODE FOR DISCRETE
STORMS AND BOWS/LEWPS WITHIN ANY LINES.

INITIALLY ELEVATED AREA OF TSTMS LATE-DAY1 ACROSS S TX -- WITH MRGL
HAIL THREAT -- MAY MOVE EWD FAST ENOUGH TO REACH WARM SECTOR AND
BECOME SFC-BASED ACROSS SRN LA DURING THIS PERIOD. 
ADDITIONALLY...SEPARATE DEVELOPMENT IS POSSIBLE IN WEAKLY CAPPED
MARINE AIR MASS THAT WILL BE CHARACTERIZED BY EFFECTIVE PARCELS
ROOTED AT SFC AND DEW POINTS 60S F.  EXPECT SFC THETAE TO OFFSET
WEAK MIDLEVEL LAPSE RATES ENOUGH TO YIELD MLCAPES TO AROUND 1000
J/KG BY AFTERNOON.  SLY/SELY SFC WINDS ALSO SHOULD BE COMMON ALONG
AND S OF MARINE/WARM FRONT...CONTRIBUTING TO ENLARGED LOW LEVEL
HODOGRAPHS.

PRIMARY UNCERTAINTIES FOR SVR POTENTIAL INVOLVE COVERAGE OF INLAND
PENETRATION OF MOST FAVORABLE WARM SECTOR AIR MASS...WITH GREATEST
SVR PROBABILITIES NEAR COAST WHERE WARM/MARINE FRONT IS MOST LIKELY
TO PENETRATE INLAND.

..EDWARDS.. 01/03/2007