[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 190605
SWODY2
SPC AC 190604

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1204 AM CST TUE DEC 19 2006

VALID 201200Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MOST IMPORTANT MID-UPPER LEVEL FEATURE FOR THIS FCST WILL BE
PRONOUNCED CYCLONE -- NOW PRESENT OVER SRN CA AND NRN BAJA.  PROGS
CONTINUE TO BECOME MORE TIGHTLY CLUSTERED IN STRONG CONSENSUS
REGARDING TRACK...EJECTION AND GEOMETRY OF THIS FEATURE DURING NEXT
FEW DAYS.  THIS LOW SHOULD MOVE ACROSS SRN ROCKIES EARLY IN
PERIOD...REACHING CENTRAL HIGH PLAINS BY 21/00Z...THEN TEMPORARILY
DECELERATING OVER WRN KS/WRN NEB REGION AS SFC CYCLONE BECOME BETTER
COLLOCATED WITH MID/UPPER VORTEX CENTER.  ASSOCIATED SFC COLD FRONT
IS FCST TO MOVE SEWD ACROSS CENTRAL/SRN TX ...REACHING COASTAL PLAIN
AROUND 21/00Z-21/06Z...THEN WEAKENING THEREAFTER.

POSITIVELY TILTED SHORTWAVE TROUGH IN SUBTROPICAL STREAM -- NOW
EVIDENT IN MOISTURE CHANNEL IMAGERY OVER ERN PACIFIC SW OF BAJA --
IS FCST TO LIFT ENEWD ACROSS N-CENTRAL/NERN MEX EARLY IN
PERIOD...THEN ACROSS TX COAST AND SRN LA BY 21/00Z.  ONLY MINOR
TIMING/AMPLITUDE DIFFERENCES EXIST WITH ASSOCIATED VORTICITY PATTERN
AMONGST SPECTRAL...NGM...AND OPERATIONAL WRF.

...S-CENTRAL/SE TX...
AT LEAST MRGL/CONDITIONAL SVR POTENTIAL MAY DEVELOP...BOUNDED ON W
BY COLD FRONT...ON N BY PROGRESSIVELY MORE STABLE BOUNDARY
LAYER...AND BY WEAKENING SHEAR WITH SWD EXTENT OVER DEEP S TX AND
GULF.

CONTINUING ELY SFC TRAJECTORIES OVER MUCH OF SRN PLAINS...EMANATING
FROM STRONG MIDWESTERN/OH VALLEY ANTICYCLONE...WILL MAINTAIN
RELATIVELY LOW THETAE AIR MASS AND KEEP OPTIMALLY HIGH THETAE AIR
FROM PENETRATING VERY FAR INLAND.  EXCEPTION MAY BE OVER
S-CENTRAL/SE TX WHERE ISALLOBARICALLY FORCED BOUNDARY LAYER
VEERING...TO MORE SLY/SELY DIRECTION...ALLOWS NARROW WEDGE OF MARINE
AIR TO MOVE INLAND PRIOR TO COLD FROPA...CHARACTERIZED BY MID 60S TO
NEAR 70 F DEW POINTS.  RICH MOISTURE AND SUBTLE LARGE SCALE ASCENT
ASSOCIATED WITH SRN STREAM TROUGH EACH MAY OFFSET VERY SMALL
MIDLEVEL LAPSE RATES AND ALLOW ENOUGH BUOYANCY TO SUPPORT SFC-BASED
TSTMS WITH AT LEAST MRGL/CONDITIONAL SVR POTENTIAL.

DEEP-LAYER VERTICAL SHEAR IS FCST TO STRENGTHEN WITH TIME THROUGH
21/00Z AS SERN EDGE OF TIGHTENING MIDLEVEL HEIGHT GRADIENT
SUPERIMPOSES ITSELF ATOP NRN PORTION OF MARINE AIR.  FCST SOUNDINGS
INDICATE ENLARGED LOW LEVEL HODOGRAPH AND 40-50 KT OF 0-6 KM SHEAR.

..EDWARDS.. 12/19/2006