[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 091645
SWODY1
SPC AC 091643

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1143 AM CDT TUE MAY 09 2006

VALID 091630Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN HIGH PLAINS TO THE
LOWER MS VALLEY....

...SRN/CENTRAL MS AND SW AL AREA TODAY...
ELEVATED THUNDERSTORMS ARE FORMING THIS MORNING ALONG A NW-SE
ORIENTED BAROCLINIC ZONE ACROSS SE MS AND SW AL.  LOW-LEVEL WAA...A
FEED OF STEEP MID LEVEL LAPSE RATES...AND MUCAPE IN EXCESS OF 2000
J/KG FROM THE SW IS SUPPORTING THIS CONVECTION.  THE STORMS MAY
GRADUALLY BECOME SURFACE BASED AS THE BOUNDARY LAYER WARMS INTO THE
80S...AND STORM COVERAGE WILL LIKELY INCREASE WITH THE APPROACH OF A
MIDLEVEL SHORTWAVE TROUGH MOVING EWD FROM NRN LA TO MS.  VERTICAL
SHEAR AND INSTABILITY ALONG THE SURFACE BOUNDARY WILL SUPPORT
SUPERCELLS WITH A THREAT FOR LARGE HAIL AND DAMAGING WINDS...AND
PERHAPS AN ISOLATED TORNADO OR TWO.

...AR/WRN TN/NW MS AREA THIS AFTERNOON...
AN MCS CONTINUES TO MOVE ESEWD OVER NRN AR AND SE MO...AND THIS
CONVECTION IS ASSOCIATED WITH A WELL-DEVELOPED COLD POOL AND MCV. 
LOW-LEVEL DESTABILIZATION IN ADVANCE OF THE ONGOING CONVECTION
SHOULD ALLOW FOR ADDITIONAL SEVERE STORM DEVELOPMENT THROUGH THE
AFTERNOON ALONG THE LEADING EDGE OF THE COLD POOL...WITH LARGE HAIL
AND DAMAGING WINDS POSSIBLE ACROSS CENTRAL/ERN AR INTO WRN TN AND NW
MS THROUGH LATE AFTERNOON.

...CENTRAL/ERN OK AND NE TX THIS AFTERNOON/EVENING...
AN OUTFLOW BOUNDARY /TRAILING SWWD FROM THE ONGOING AR STORMS/ IS
MOVING SEWD ACROSS SE OK.  THIS BOUNDARY WILL LIKELY CONTINUE SEWD
ACROSS THE ARKLATEX REGION THIS AFTERNOON...WHILE THE WRN PORTION OF
THE OUTFLOW SHOULD STALL ACROSS CENTRAL OK...JUST NE OF A TRIPLE
POINT LOW BETWEEN FSI AND OUN. S OF THE LOW...A DRYLINE WILL BECOME
BETTER DEFINED ACROSS SRN OK/N TX.

THE 12Z SOUNDINGS FROM OUN/FWD SHOW VERY STEEP MID LEVEL LAPSE RATES
ABOVE A MOIST BOUNDARY LAYER...AS WELL AS A STRONG CAP WITH
CONVECTIVE TEMPERATURES IN THE 90S.  WITH LITTLE LARGE SCALE FORCING
FOR ASCENT...CONVECTIVE INITIATION WILL RELY ALMOST SOLELY ON THE
COMBINED IMPACTS OF DAYTIME HEATING AND MESOSCALE LIFT ALONG THE
OUTFLOW AND NEAR THE TRIPLE POINT LOW. IF STORMS CAN FORM...EXTREME
INSTABILITY /MLCAPE NEAR 4000 J/KG/ AND MODEST VERTICAL SHEAR WILL
SUPPORT A THREAT FOR SUPERCELLS WITH VERY LARGE HAIL...DAMAGING
WINDS...AND A COUPLE OF TORNADOES.

...TX PANHANDLE/SW KS/WRN OK OVERNIGHT...
A SHORTWAVE TROUGH OVER UT THIS MORNING IS FORECAST TO REACH THE SRN
HIGH PLAINS TONIGHT.  A MOIST UPSLOPE FLOW REGIME MAY SUPPORT
THUNDERSTORM DEVELOPMENT BY LATE EVENING/EARLY TONIGHT OVER THE
TX/OK PANHANDLES INTO SW KS...WITH CONVECTION EXPECTED TO GROW INTO
A LARGER MCS ACROSS WRN/NWRN OK BY EARLY WEDNESDAY.  LARGE HAIL AND
DAMAGING WINDS WILL BE POSSIBLE WITH THIS ACTIVITY...ESPECIALLY AS
THE STORMS ENCOUNTER GREATER INSTABILITY LATE TONIGHT ACROSS OK.

...SE FL THIS AFTERNOON...
THE REMNANTS OF OVERNIGHT CONVECTION ARE MOVING SEWD FROM CENTRAL
TOWARD SE FL.  SOME DAYTIME HEATING PRIOR TO THE ARRIVAL OF ANVIL
DEBRIS CLOUDS AND BOUNDARY LAYER DEWPOINTS IN THE UPPER 60S TO NEAR
70 F WILL RESULT IN SUFFICIENT INSTABILITY FOR A FEW
STRONG/MARGINALLY SEVERE STORMS THIS AFTERNOON.  THE MORE PROBABLE
AREAS FOR DEVELOPMENT WILL BE ALONG THE SE MOVING OUTFLOW
BOUNDARY...AND WHERE THIS BOUNDARY INTERSECTS THE E COAST SEA
BREEZE.  ISOLATED DOWNBURST WINDS AND SMALL HAIL WILL BE THE MAIN
THREATS.

..THOMPSON/TAYLOR.. 05/09/2006