SWODY1
SPC AC 140100
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 PM CDT THU MAR 13 2008
VALID 140100Z - 141200Z
..THERE IS A SLGT RISK OF SVR TSTMS FROM ERN PARTS OF THE OK AND
EXTREME ERN TX INTO THE LOWER MS VALLEY...
..ERN OK THROUGH NERN TX AND AR...
QUASISTATIONARY FRONT EXTENDS FROM A SURFACE LOW NEAR OKLAHOMA CITY
NEWD THROUGH NERN OK NEAR TULSA AND INTO SRN MO. A DRY LINE EXTENDS
SWD FROM THE LOW THROUGH S CNTRL OK...N CNTRL TX AND FARTHER SOUTH
TO EAST OF DEL RIO. AXIS OF PARTIALLY MODIFIED GULF MOISTURE WITH
MID 50S DEWPOINTS HAS RETURNED THROUGH ERN TX...ERN OK AND THE LOWER
MS VALLEY BENEATH 7.5-8 C/KM MID LEVEL LAPSE RATES...CONTRIBUTING TO
MLCAPE FROM 1000 TO 1500 J/KG.
ELEVATED STORMS CONTINUE OVER AR ON NOSE OF THE LOW LEVEL JET WHERE
CAP IS WEAKER ALONG ERN PERIPHERY OF THE EML. LARGE HAIL WILL REMAIN
THE PRIMARY THREAT WITH THIS ACTIVITY...BUT ISOLATED DAMAGING WIND
WILL ALSO BE POSSIBLE GIVEN LARGE BOUNDARY LAYER
TEMPERATURE-DEWPOINT SPREADS. SURFACE BASED STORMS HAVE BEEN LIMITED
SO FAR AS A RESULT OF A WARM EML HAVING OVERSPREAD THE WARM SECTOR.
HOWEVER...INFLUENCE OF LARGE SCALE ASCENT ACCOMPANYING EWD ADVANCING
SHORTWAVE TROUGH IS SPREADING EWD THROUGH ERN OK...NERN TX AND AR.
THE CAP HAS FINALLY WEAKENED ENOUGH FOR STORMS TO BEGIN DEVELOPING
OVER E CNTRL OK IN VICINITY OF THE DRYLINE AND NERN OK ALONG THE
QUASISTATIONARY FRONT. MLCAPE FROM 500 TO 1000 J/KG...-20 C AT 500
MB...AND STEEP MID LEVEL LAPSE RATES WILL SUPPORT A THREAT OF LARGE
HAIL WITH THIS ACTIVITY. THE FRONT WILL LIKELY SHIFT SEWD WITH TIME
AS THE SHORTWAVE TROUGH ADVANCES EWD...AND ADDITIONAL STORMS MAY
CONTINUE DEVELOPING ALONG AND IN ADVANCE OF THE FRONT FROM ERN OK
INTO AR THIS EVENING. ACTIVITY WILL PROBABLY UNDERGO A WEAKENING
TREND AS IT MOVES TOWARD THE TN VALLEY LATER TONIGHT WHERE
INSTABILITY WILL BE WEAKER...BUT MID LEVEL LAPSE RATES AND
INSTABILITY MIGHT STILL SUPPORT A THREAT FOR MARGINALLY SEVERE HAIL.
..ERN TX THROUGH THE LOWER MS VALLEY...
IT APPEARS THUNDERSTORM DEVELOPMENT ALONG THE DRYLINE IS BECOMING
INCREASINGLY UNLIKELY GIVEN INHIBITING EFFECTS OF THE EML...THE
STABILIZING BOUNDARY LAYER AND TENDENCY FOR LARGE SCALE ASCENT TO
SHIFT EAST OF THE DRYLINE WITH TIME. FARTHER EAST...00Z RAOBS FROM
SHREVEPORT AND LAKE CHARLES STILL SHOW PRESENCE OF A CAP AROUND 700
MB ALONG ERN EDGE OF THE EML. GIVEN LACK OF A LOW LEVEL FOCUS IN
THIS REGION...SURFACE BASED THUNDERSTORM DEVELOPMENT APPEARS
LIMITED. HOWEVER...ELEVATED STORM WILL REMAIN POSSIBLE WITHIN ZONE
OF ASCENT EAST OF ADVANCING SHORTWAVE TROUGH...ESPECIALLY ACROSS NRN
LA NEXT FEW HOURS.
FARTHER SOUTH...A CLUSTER OF THUNDERSTORMS HAS DEVELOPED OFF THE LA
COAST IN ASSOCIATION WITH AN EWD ADVANCING IMPULSE OVER THE NWRN
GULF. MOST OF THIS ACTIVITY WILL REMAIN OFFSHORE. HOWEVER...SOME OF
THESE STORMS MAY SPREAD INTO SERN LA THIS EVENING. THESE STORMS ARE
EXPECTED TO REMAIN SLIGHTLY ELEVATED. HOWEVER...BULK SHEAR WILL BE
SUPPORTIVE OF UPDRAFT ROTATION WITH LARGE HAIL AND ISOLATED DAMAGING
WIND THE MAIN THREATS.
.DIAL.. 03/14/2008
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