SWODY2
SPC AC 230640
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1240 AM CST THU DEC 23 2010
VALID 241200Z - 251200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
LONGWAVE PATTERN WILL REMAIN CHARACTERIZED BY RIDGING OFFSHORE ATLC
AND PAC COASTS...AND RIDGING OVER ROCKIES/HIGH PLAINS REGION.
STG MID-UPPER LEVEL SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE
CHANNEL IMAGERY OVER SERN CA AND LOWER CO RIVER REGION -- IS FCST TO
MOVE THROUGH MEAN RIDGE POSITION DAY-1. BY 24/12Z...TROUGH SHOULD
ASSUME POSITIVE TILT FROM S-CENTRAL KS SWWD ACROSS PERMIAN BASIN
REGION. NRN-STREAM HEIGHT FALLS OVER MID/UPPER MS VALLEY
REGION...AHEAD OF APCHG SPEED MAX...WILL SPREAD SEWD ACROSS MUCH OF
SERN CONUS DURING THIS PERIOD. THIS WILL LEAD TO
DEAMPLIFICATION/ACCELERATION OF SRN-STREAM PERTURBATION...WHICH
SHOULD PHASE/MERGE WITH BROADER TROUGH OVER AL AROUND END OF PERIOD.
AT SFC...COLD FRONT WILL MOVE SEWD FROM SRN HIGH PLAINS ACROSS
TX/LA...WITH OCNL/WEAK WAVE LOWS. BY END OF PERIOD...ONE OF THESE
LOWS SHOULD BECOME SOMEWHAT BETTER DEFINED INVOF COASTAL
MS/AL...WITH COLD FRONT SWWD ACROSS MS RIVER MOUTH AREA AND NWRN
GULF.
...CENTRAL TX TO OZARKS AND MS DELTA REGION...
WRN PORTION OF TSTM OUTLOOK REPRESENTS CARRY-OVER FROM REGIME
DISCUSSED IN DAY-1 OUTLOOK...AS BAND OF ELEVATED TSTMS ACCESSES MRGL
LOW-LEVEL MOISTURE...AMIDST WEAK LOW-MIDLEVEL LAPSE RATES SUPPORTING
LESS THAN 300 J/KG MUCAPE. BULK OF CONVECTION SHOULD REMAIN ON COLD
SIDE OF FRONT. HOWEVER...BAND OF CONVECTION MAY DEVELOP ALONG FRONT
DURING DAY...SUPPORTED BY SFC DIABATIC HEATING AND FRONTAL ASCENT.
UPSTREAM AIR MASS ACROSS GULF DOES NOT CONTAIN RESERVOIR OF HIGH-PW
AIR BECAUSE OF SERIES OF PRIOR FROPAS...SO EVEN WITH SKIN-LAYER DEW
POINTS REACHING LOW-MID 60S OVER PORTIONS TX COAST...MOISTURE
QUALITY MAY NOT BE SUFFICIENT TO OFFSET WEAK LAPSE RATES ALOFT FOR
GENERATING DEEP BUOYANCY. THEREFORE...TSTM COVERAGE IS IN QUESTION
WHERE INFLOW PARCELS ARE SFC-BASED OVER LAND. SVR THREAT IS
NON-ZERO...MAINLY FOR GUSTS INVOF MID-UPPER TX COAST DURING
AFTERNOON...HOWEVER IT IS TOO WEAK AND CONDITIONAL TO DRAW AOA 5%
PROBABILITIES ATTM. WITH TIME...CONVECTIVE REGIME SHOULD TAPER SEWD
ON N END...AS STRONGEST SUPPORTIVE LARGE-SCALE ASCENT AND ELEVATED
CONVECTIVE FORCING OUTRUN NRN EXTENT OF PLUME OF MRGL THETAE.
..EDWARDS.. 12/23/2010
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