[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 050544
SWODY1
SPC AC 050542

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1242 AM CDT FRI MAY 05 2006

VALID 051200Z - 061200Z

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

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTH ATLANTIC COAST
STATES....

SHORT WAVE IMPULSE ON NOSE OF SEASONABLY STRONG NORTH
CENTRAL/NORTHEAST PACIFIC POLAR JET IS ALREADY APPROACHING THE
BRITISH COLUMBIA/PACIFIC NORTHWEST COAST.  MOST VIGOROUS PORTION OF
SYSTEM IS PROGGED TO CONTINUE INLAND ACROSS THE CASCADES AND
CANADIAN ROCKIES TODAY...WHILE WEAKER SOUTHERN PORTION DIGS IN
SOUTHERN STREAM...TOWARD NORTHERN/CENTRAL CALIFORNIA.  IN RESPONSE
TO THESE DEVELOPMENTS...SIGNIFICANT SOUTHERN BRANCH TROUGH WILL BE
FORCED EASTWARD OUT OF THE GREAT BASIN/SOUTHERN PLATEAU.  MODELS
SUGGEST THAT THIS WILL OCCUR IN A MORE OR LESS PIECE MEAL
FASHION...WITH A SERIES OF SMALLER SCALE IMPULSES PROGRESSING EAST
OF THE ROCKIES INTO THE SOUTH CENTRAL STATES.

FARTHER DOWNSTREAM...TO THE SOUTH/EAST OF AN AMPLIFYING NORTHERN
BRANCH TROUGH...A CONVECTIVELY GENERATED/ENHANCED IMPULSE IN THE
WEAKER SOUTHERN STREAM IS FORECAST TO LIFT OUT OF THE TENNESSEE
VALLEY.  SYSTEM IS EXPECTED TO BECOME INCREASINGLY SHEARED AS IT
CROSSES THE CENTRAL/SOUTHERN APPALACHIANS BY MID DAY...BEFORE
CONTINUING THROUGH MID/SOUTHERN ATLANTIC COASTAL AREAS LATER
TODAY/TONIGHT.

...SOUTHERN PLAINS...
CONSIDERABLE STRENGTHENING OF MID-LEVEL FLOW /ON THE ORDER OF 40 TO
50 KT/ IS FORECAST IN A CYCLONIC BELT ACROSS THE SOUTHERN
ROCKIES/NORTHERN MEXICAN PLATEAU THROUGH MUCH OF TEXAS TODAY.  WHILE
THIS WILL CONTRIBUTE TO AN INCREASINGLY FAVORABLE KINEMATIC
ENVIRONMENT FOR SUPERCELLS AND SEVERE STORMS AS COMPARED TO RECENT
DAYS...CONVECTIVE POTENTIAL THIS PERIOD IS MORE UNCERTAIN DUE TO
INFLUENCE OF SEVERAL DAYS OF WIDESPREAD CONVECTION.  CONSIDERABLE
CONVECTION COULD BE ONGOING EARLY IN THE PERIOD ACROSS PARTS OF
SOUTHERN AND EASTERN TEXAS...ASSOCIATED WITH REMNANTS OF WEAKENING
CONVECTIVE CLUSTER...WITH NEW DEVELOPMENT POSSIBLE ACROSS THE SOUTH
PLAINS IN ASSOCIATION WITH LEAD IMPULSE PROGRESSING EAST OF THE
SOUTHERN ROCKIES.

STEEP LAPSE RATE ENVIRONMENT AND STRONGER SURFACE HEATING MAY
ULTIMATELY BE CONFINED TO THE IMMEDIATE VICINITY OF THE RIO GRANDE 
AND PECOS VALLEYS.  VERY MOIST AIR IS IN PLACE ACROSS THE RIO GRANDE
VALLEY WITH 70F DEW POINTS AS FAR NORTH AS DEL RIO.  ADVECTION OF
THIS MOIST TONGUE WESTWARD THROUGH THE PECOS VALLEY SHOULD OCCUR
TODAY...AND WILL CONTRIBUTE TO AT LEAST A NARROW CORRIDOR OF
MODERATE TO STRONG INSTABILITY...WITH MIXED LAYER CAPE REACHING
2000-3000 J/KG BY PEAK HEATING.

AS NEXT UPPER IMPULSE PROGRESSES EAST OF THE SOUTHERN ROCKIES THIS
AFTERNOON...INITIATION OF ADDITIONAL INTENSE CONVECTION IS EXPECTED
ALONG OUTFLOW/SURFACE FRONT ADVANCING SOUTHWARD TOWARD THE MIDLAND
AREA...AND ALONG DRY LINE NEAR THE PECOS RIVER.  ISOLATED SUPERCELLS
ARE EXPECTED...WITH POTENTIAL FOR VERY LARGE HAIL AND TORNADOES. 
THIS ACTIVITY IS EXPECTED TO CONTINUE INTO EARLY EVENING...BEFORE
EVOLVING UPSCALE INTO A STRONG/SEVERE MESOSCALE CONVECTIVE SYSTEM AS
INFLOW STRENGTHENS ASSOCIATED WITH SOUTHEASTERLY LOW-LEVEL JET
THROUGH THE RIO GRANDE VALLEY.

...SOUTH ATLANTIC COAST STATES...
MOISTENING BOUNDARY LAYER AND STRONG SURFACE HEATING IS EXPECTED TO
CONTRIBUTE TO DESTABILIZING ENVIRONMENT TO THE LEE OF THE SOUTHERN
APPALACHIANS TODAY. MODELS SUGGEST MIXED LAYER CAPE WILL REACH
1000-2000 J/KG BY PEAK AFTERNOON HEATING.  THIS SHOULD BE SUFFICIENT
FOR SCATTERED VIGOROUS CONVECTIVE DEVELOPMENT FROM GEORGIA THROUGH
THE CAROLINAS...AIDED BY FORCING ASSOCIATED WITH WEAK SOUTHERN
BRANCH IMPULSE.  BELT OF 20 TO 30 KT WESTERLY MID-LEVEL FLOW MAY
ACCOMPANY THIS FEATURE...CONTRIBUTING TO MODERATE STORM
MOTIONS...POSSIBLY ENHANCING RISK FOR DAMAGING WINDS IN STRONGER
STORMS.  HAIL APPROACHING OR EXCEEDING SEVERE LIMITS MAY ALSO OCCUR.

..KERR/GRAMS.. 05/05/2006