[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 121734
SWODY2
SPC AC 121733

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1233 PM CDT FRI MAY 12 2006

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL
GULF COAST STATES...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN TX/SRN AR/LA...

...SYNOPSIS...
BLOCKING PATTERN WILL PERSIST INTO THE DAY 2 PERIOD AS LARGE CLOSED
UPPER LOW...NOW CENTERED OVER THE WRN GREAT LAKES...SETTLES SWD
ACROSS THE OH VALLEY...AND THE UPSTREAM RIDGE BUILDS NWD OVER THE
WRN STATES/SWRN CANADA.  A COUPLE OF WEAK SHORT WAVE TROUGHS WITHIN
STRONG NWLY FLOW REGIME ALONG WRN/SRN PERIPHERIES OF UPPER CYCLONE
WILL AID IN THUNDERSTORMS ACROSS THE CENTRAL GULF COAST STATES...AND
THEN LATE IN THE PERIOD OVER SERN PLAINS/LOWER MS VALLEY.

AT THE SURFACE...A WEAK BOUNDARY EXTENDING FROM THE TX PANHANDLE ESE
THROUGH RED RIVER/LOWER MS VALLEYS TO FL PANHANDLE IS EXPECTED TO
REMAIN NEARLY STATIONARY SATURDAY.  THIS BOUNDARY SHOULD THEN MOVE
SWD SATURDAY NIGHT AS COLD FRONT MOVES SWD INTO THE SRN PLAINS AND
THROUGH TN VALLEY TO GULF COAST STATES.

...GULF COAST STATES...
MOISTURE RETURN BY DAY 2 ACROSS THE GULF COAST STATES IS EXPECTED TO
BE SUFFICIENT /SURFACE DEWPOINTS IN THE UPPER 50S TO AROUND 60/ FOR
A THREAT OF SEVERE STORMS...GIVEN AN ELEVATED MIXED LAYER/STEEP
LAPSE RATE ENVIRONMENT ADVECTING EWD ATOP THIS LOW-LEVEL MOISTENING.
SATURDAY AFTERNOON MLCAPE VALUES SHOULD RANGE FROM 800-1200 J/KG.

AT THE START OF THE PERIOD...ELEVATED THUNDERSTORMS MAY BE ONGOING
ACROSS ERN OK INTO THE LOWER MS VALLEY.  THIS ACTIVITY WILL BE
ASSOCIATED WITH WAA ALONG THE NOSE OF A WSWLY ORIENTED LLJ.  THIS
WAA ACTIVITY WILL SPREAD EWD ACROSS THE GULF COAST STATES AS
ASSOCIATED WEAK MID LEVEL IMPULSE TRACKS ESEWD ACROSS THE REGION. 
STORMS SHOULD BECOME SURFACE BASED BY SATURDAY AFTERNOON AS SURFACE
HEATING WEAKENS THE CAP...WITH THE INSTABILITY AND STRONG DEEP LAYER
SHEAR PER 50-70 KT WNWLY MID LEVEL JET SUPPORTING ORGANIZED STORMS/
SUPERCELLS.

...ERN TX/SRN AR/LA...
STRONGER CAP FURTHER WEST ACROSS LA INTO TX IS EXPECTED TO PRECLUDE
THUNDERSTORM DEVELOPMENT UNTIL SATURDAY EVENING ALONG/N OF
STATIONARY BOUNDARY...AND APPROACHING COLD FRONT.  INCREASING SWLY
LLJ/WAA ACROSS ERN TX AND MOISTENING LOW LEVEL AIR MASS EXPECTED TO
RESULT IN SUFFICIENT DESTABILIZATION FOR ELEVATED THUNDERSTORMS AS A
SHORT WAVE TROUGH APPROACHES ERN TX/LOWER MS VALLEY SATURDAY NIGHT. 
MODERATE INSTABILITY AND STRONG EFFECTIVE BULK SHEAR VALUES EXPECTED
TO SUPPORT POTENTIAL FOR ELEVATED SUPERCELLS...WITH ACTIVITY
EVOLVING INTO AN MCS AND TRACKING SE ACROSS ERN TX/LA SATURDAY
NIGHT.

A CONDITIONAL THREAT FOR SEVERE AND LOWER SEVERE PROBABILITIES EXIST
ACROSS W TX WHERE MODELS DIFFER ON THE DEVELOPMENT OF SURFACE BASED
STORMS LATE SATURDAY AFTERNOON.  IF ACTIVITY DEVELOPS...THEN
INSTABILITY/SHEAR VALUES WOULD SUPPORT A FEW ORGANIZED STORMS WITH
POTENTIAL FOR UPSCALE GROWTH INTO AN MCS SATURDAY EVENING.  PARTS OF
THIS REGION MAY REQUIRE AN UPGRADE IN SEVERE PROBABILITIES IN LATER
OUTLOOKS.

..PETERS.. 05/12/2006