[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 171642
SWODY2
SPC AC 171641

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1041 AM CST SUN DEC 17 2006

VALID 181200Z - 191200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

WAVE TRAIN OF POLAR WESTERLIES WILL EXIST FROM THE GULF OF AK EWD
ACROSS CANADA WHILE LOWER LATITUDE TROUGH BECOMES PROGRESSIVELY CUT
OFF OVER THE LOWER CO VALLEY.  IN THE LOW-LEVELS...PASSAGE OF NRN
BRANCH SHORT WAVE TROUGH THROUGH CNTRL CANADA WILL SERVE TO
STRENGTHEN SURFACE HIGH OVER THE NRN/CNTRL PLAINS INTO UPPER GREAT
LAKES.  AS THIS OCCURS...COLD FRONT WILL CONTINUE TO PUSH SWD
THROUGH THE MIDDLE INTO LOWER MS VALLEY WWD THROUGH THE SRN PLAINS
TO DEVELOPING LOW PRESSURE ALONG THE AZ/NM BORDER.

...SWRN DESERTS INTO THE SRN PLAINS...

RATHER COLD MID-LEVEL TEMPERATURES OF -26 TO -28 C AT 500 MB
ASSOCIATED WITH EVOLVING UPPER LOW ARE EXPECTED TO LARGELY
CONTRIBUTE TO STEEPENING LAPSE RATES INVOF DEVELOPING SURFACE LOW
AND TROUGH.  INCREASED DEEP-LAYER FORCING FOR ASCENT COUPLED WITH
THE RESULTING MARGINAL INSTABILITY SHOULD SUPPORT AN INCREASE IN
SHOWER AND ISOLATED/SCATTERED TSTM DEVELOPMENT MONDAY ACROSS
PORTIONS OF AZ/NM.

FARTHER TO THE E OVER TX...12Z RAOBS AND SURFACE OBSERVATIONS
INDICATE LOW-LEVEL MOISTURE INCREASING BELOW QUITE POOR MID-LEVEL
LAPSE RATES.  HEIGHT FALLS DOWNSTREAM FROM SWRN U.S. UPPER LOW
SHOULD CONTRIBUTE TO SOME MID-LEVEL COOLING/STEEPENING LAPSE RATES
OVER THE SRN HIGH PLAINS DURING THE PERIOD WITH POCKETS OF
WEAK...ELEVATED INSTABILITY DEVELOPING.  INCREASING ISENTROPIC
ASCENT OWING TO STRENGTHENING SELY LLJ NEAR AND N OF SURFACE COLD
FRONT SHOULD SUPPORT AN INCREASE IN SHOWER AND TSTM DEVELOPMENT
MAINLY MONDAY NIGHT FROM PORTIONS OF SERN/E-CNTRL NM EWD INTO THE
RED RIVER VALLEY.

..MEAD.. 12/17/2006