[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 240454
SWODY2
SPC AC 240453

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1053 PM CST THU NOV 23 2006

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A SLOW EWD PROGRESSION OF WRN CONUS LONG WAVE TROUGH /COMPRISED OF
DISTINCT POLAR AND SUBTROPICAL JET BRANCHES/ IS FORECAST DURING THE
DAY TWO PERIOD WITH PERSISTENT RIDGING OVER THE SERN STATES.  SHORT
WAVE TROUGH NOW NEAR 30N AND 126W IS FORECAST TO TRANSLATE THROUGH
THE SUBTROPICAL BRANCH...EVENTUALLY LIFTING NEWD INTO THE UPPER
MIDWEST SATURDAY NIGHT.  IN THE LOW-LEVELS...PRIMARY BAROCLINIC ZONE
WILL EXIST FROM LOW PRESSURE OVER THE NRN HIGH PLAINS EWD INTO THE
UPPER GREAT LAKES WITH DOMINANT RIDGING FROM THE CANADIAN MARITIMES
INTO THE GULF OF MEXICO.  THIS RIDGING WILL TEND TO LIMIT THE
DEGREE/QUALITY OF LOW-LEVEL MOISTURE RETURN ACROSS TX/LA.

...PACIFIC NW COAST TO NRN ROCKIES...

COLD MID-LEVEL TEMPERATURES /-25 TO -35 C AT 500 MB/ WILL BE
MAINTAINED THROUGH THE PERIOD ON CYCLONIC SIDE OF POLAR
JET...EFFECTIVELY CONTRIBUTING TO STEEP LAPSE RATES AND WEAK
CONVECTIVE INSTABILITY.  STRONG SHORT WAVE TROUGH INITIALLY OVER
WA/ORE SATURDAY MORNING WILL SHIFT EWD...LIKELY PROVIDING SUFFICIENT
BACKGROUND DESTABILIZATION/FORCING FOR ISOLATED TSTM DEVELOPMENT
ACROSS THE NRN INTERMOUNTAIN REGION INTO SATURDAY EVENING.  FARTHER
UPSTREAM ALONG THE WA/ORE COAST...THE STEEP LAPSE RATES COUPLED WITH
MOIST ONSHORE FLOW AND HEIGHT FALLS AHEAD OF NEXT SHORT WAVE TROUGH
DROPPING SEWD FROM THE GULF OF AK WILL BE SUPPORTIVE OF ISOLATED
TSTMS AS WELL.

...SWRN DESERTS INTO THE FOUR CORNERS REGION...

SHORT WAVE TROUGH EMBEDDED IN SUBTROPICAL BRANCH INITIALLY ALONG OR
JUST OFF THE SRN CA COAST IS EXPECTED TO MOVE EWD THROUGH THE LOWER
CO VALLEY AND EVENTUALLY THE FOUR CORNERS REGION SATURDAY AND
SATURDAY NIGHT.  DEVELOPING STEEP LAPSE RATES AHEAD OF THIS FEATURE
WILL LARGELY CONTRIBUTE TO WEAK CONVECTIVE INSTABILITY...ESPECIALLY
DURING THE MID/LATE AFTERNOON AND EARLY EVENING HOURS...FOR ISOLATED
TO SCATTERED TSTMS FROM AZ NEWD INTO WRN/CNTRL CO.

...UPPER MIDWEST...

AS MENTIONED ABOVE...LEAD SRN BRANCH IMPULSE NOW NEAR 30N AND 126W
IS FORECAST TO LIFT NEWD TOWARD THE REGION...THOUGH LATEST MODEL
GUIDANCE INDICATE SLIGHT TIMING DIFFERENCES.  IT APPEARS SOME
POTENTIAL EXISTS FOR AT LEAST A FEW ELEVATED TSTMS...MAINLY SATURDAY
NIGHT...AS LOW-LEVEL WAA AND ISENTROPIC ASCENT INCREASE AHEAD OF THE
SHORT WAVE TROUGH.

..MEAD.. 11/24/2006