[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210539
SWODY1
SPC AC 210538

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1138 PM CST TUE DEC 20 2005

VALID 211200Z - 221200Z

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 80 NNW UIL 20 NNW HQM
25 E ONP 35 NE ACV 45 E ACV 40 S MHS 30 NE RBL 45 E SAC MER 30 NNW
PRB 75 WSW VBG.

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A GENERAL DE-AMPLIFICATION OF LARGE-SCALE PATTERN IS FORECAST
THROUGH THE DAY ONE PERIOD OVER THE CONUS...EXCEPT OVER THE SRN
STATES AND NRN GULF OF MEXICO WHERE TROUGHING WILL PERSIST.  IN THE
W...NEXT IN A SERIES OF VIGOROUS SHORTWAVES TROUGH IS CURRENTLY
OBSERVED NEAR 40N/136W.  THIS FEATURE AND SEVERAL OTHER
SMALLER-SCALE PERTURBATIONS ARE EXPECTED TO BREAK DOWN W CONUS RIDGE
WITH MID/HIGH-LEVEL FLOW BECOMING MORE WSWLY ACROSS THE PACIFIC
NW...GREAT BASIN INTO NRN ROCKIES.

IN THE LOW-LEVELS...AFOREMENTIONED UPPER TROUGH OVER THE GULF OF
MEXICO AND SERN STATES WILL REINFORCE SURFACE ANTICYCLONE OVER THE
SAME AREA...RESULTING IN LARGELY OFFSHORE FLOW ACROSS THE GULF
BASIN.

...PACIFIC NW COAST INTO CNTRL CA...

ISOLATED TO WIDELY SCATTERED TSTMS WILL BECOME INCREASINGLY POSSIBLE
TODAY AND TONIGHT OWING TO THE INCREASED LARGE-SCALE FORCING AND
RESULTANT DESTABILIZATION ASSOCIATED WITH THE PRIMARY SHORTWAVE
TROUGH AND EMBEDDED SMALLER-SCALE PERTURBATIONS.  ACTIVITY WILL
LIKELY REMAIN CLOSELY TIED TO THE COAST OVER WA AND ORE WHERE MOIST
ONSHORE FLOW COUPLED WITH THE STEEPENING MID-LEVEL LAPSE RATES
CONTRIBUTE TO A WEAKLY UNSTABLE ENVIRONMENT.  FARTHER TO THE
S...DESPITE WEAKER FORCING VIA DPVA...IT APPEARS THAT PERSISTENT
LOW-LEVEL WAA WILL SUFFICIENTLY DESTABILIZE AIR MASS TO SUPPORT TSTM
DEVELOPMENT FROM THE CA COAST INTO THE CNTRL VALLEY.

..MEAD.. 12/21/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT WILL BE
DISCONTINUED ON 14 FEBRUARY 2006 BUT WILL REMAIN AVAILABLE
IN THE FOLLOWING PRODUCTS:

   WMO HEADER:       AWIPS ID:
   WUUS01            PTSDY1
   WUUS02            PTSDY2
   WUUS03            PTSDY3

A SERVICE CHANGE NOTICE ...SCN05-39... PROVIDES DETAILS
ON THE TRANSITION. FOR ADDITIONAL DETAILS SEE THE FOLLOWING
WEB ADDRESS USING LOWER CASE LETTERS:
WWW.NWS.NOAA.GOV/OM/NOTIF.HTM