[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 050054
SWODY1
SPC AC 050052

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT THU MAY 04 2006

VALID 050100Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT ACROSS PARTS OF THE SRN
PLAINS....

...THERE IS A SLGT RISK OF SVR TSTMS THIS EVE ACROSS PARTS OF THE
CNTRL GULF STATES....

A COLD INTRUSION TO THE LEE OF THE ROCKIES HAS OCCURRED IN
ASSOCIATION WITH A BROAD NORTHERN BRANCH TROUGH NOW SLOWLY SHIFTING
THROUGH THE EASTERN CANADIAN PROVINCES...AND PARTS OF THE UPPER
MIDWEST INTO THE NORTHEAST STATES.  SURFACE RIDGE HAS BECOME
CENTERED BENEATH CONFLUENCE OF NORTHERN AND SOUTHERN BRANCHES OF
WESTERLIES...ACROSS THE NORTHERN/CENTRAL PLAINS...WITH ASSOCIATED
FRONTAL ZONE NOW EXTENDING FROM THE LOWER GREAT LAKES THROUGH THE
LOWER OHIO VALLEY INTO THE SOUTH CENTRAL HIGH PLAINS.  SEVERAL
CONVECTIVE OUTFLOWS HAVE SUPPRESSED DEEPER BOUNDARY LAYER MOISTURE
TO THE SOUTH OF THIS FRONTAL ZONE...AND WILL REMAIN THE FOCUS FOR
THE PRIMARY CONVECTIVE DEVELOPMENT THROUGH THE REMAINDER OF THIS
FORECAST PERIOD.

...SOUTHERN PLAINS...
OUTFLOW BOUNDARY...EXTENDING ACROSS THE TEXAS HILL COUNTRY AND
TRANSPECOS REGION...AND SURFACE FRONTAL ZONE...ACROSS THE TEXAS
SOUTH PLAINS INTO EASTERN NEW MEXICO...ARE PROVIDING THE FOCUS FOR
ONGOING SCATTERED VIGOROUS THUNDERSTORM ACTIVITY.  LOW-LEVEL FLOW
ACROSS THIS REGION IS RATHER WEAK...BUT VEERING PROFILES WITH HEIGHT
BENEATH MODERATE WESTERLY MID LEVEL FLOW IS CONTRIBUTING TO
SUFFICIENT SHEAR FOR ISOLATED SUPERCELLS IN ENVIRONMENT WITH MIXED
LAYER CAPE OF 2000 TO 3000 J/KG.  THIS ACTIVITY MAY PERSIST THROUGH
02-03Z...BUT WITH ONSET OF SURFACE COOLING...NOCTURNAL SOUTHERLY
LOW-LEVEL JET SEEMS LIKELY TO SUPPORT CONSOLIDATING/EXPANDING
CONVECTIVE CLUSTER NEAR/EAST OF SAN ANGELO.  AS THIS
OCCURS...UNSATURATED LOW/MID-LEVELS WILL ENHANCE EVAPORATIVE COOLING
NEAR HEAVY PRECIPITATION CORES...AND A DOWNBURST OR TWO MAY OCCUR
WITH POTENTIALLY DAMAGING WINDS ON OUTWARD SURGING GUST FRONTS.

...LOWER MISSISSIPPI VALLEY/GULF STATES...
CONVECTIVELY GENERATED UPPER IMPULSE/MID-LEVEL CYCLONIC VORTICITY
CENTER IS PROVIDING SUPPORT FOR ONGOING CONVECTIVE CLUSTER NOW
SPREADING ACROSS THE LOWER MISSISSIPPI VALLEY. THIS IS EMBEDDED
WITHIN GENERALLY WEAK FLOW REGIME BETWEEN CONFLUENT BELTS OF POLAR
WESTERLIES TO THE NORTH...AND SUBTROPICAL WESTERLIES TO THE SOUTH.
HOWEVER...THERMODYNAMIC PROFILES SEEM SUPPORTIVE OF A CONTINUING
RISK FOR MARGINALLY SEVERE HAIL/GUSTY WINDS WITH CONVECTIVE SYSTEM
AS IT SPREADS ACROSS NORTHERN/CENTRAL MISSISSIPPI THROUGH 03-04Z. 
THEREAFTER...CONVECTION IS EXPECTED TO WEAKEN IN MORE STABLE/
STABILIZING ENVIRONMENT.

..KERR.. 05/05/2006