Sunday, November 25, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 251611
SWODY1
SPC AC 251609

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CST SUN NOV 25 2007

VALID 251630Z - 261200Z

..THERE IS A SLGT RISK OF SVR TSTMS TODAY INTO TONIGHT ACROSS THE N
CENTRAL GULF COAST...

..N CENTRAL GULF COAST THROUGH TONIGHT...
THE CLOSED MID LEVEL LOW OVER THE BIG BEND REGION IS BEGINNING TO
TURN NEWD...AND IS FORECAST TO REACH SE OK BY EARLY MONDAY. AT THE
SURFACE...A LOW JUST OFF THE SW LA COAST WILL DEVELOP NNEWD ACROSS
LA TOWARD MEM BY THE END OF THE PERIOD...WHILE A TRAILING COLD FRONT
MOVES EWD ACROSS LA/MS AND THE NW GULF OF MEXICO. E AND SE OF THE
SURFACE LOW...A WARM FRONT ACROSS THE N CENTRAL/NE GULF AND N FL
WILL LIFT NWD ACROSS SRN LA/MS TODAY...AND INTO SRN AL/GA LATER
TONIGHT. THE PRIMARY SEVERE STORM THREAT AREA WILL BE NEAR THIS
WARM FRONT THROUGH TONIGHT.

BUOY OBSERVATIONS SHOW 67-70 F DEWPOINTS ACROSS THE NRN GULF OF
MEXICO TO THE S OF THE WARM FRONT. MEANWHILE...VISIBLE IMAGERY AND
RADAR MOSAICS REVEAL WIDESPREAD CLOUDS/RAIN SPREADING NEWD ACROSS LA
TOWARD MS...AND INLAND PROGRESS OF THE SURFACE WARM SECTOR MAY BE
LIMITED TO AREAS ALONG AND S OF I-10 DURING THE DAY IN LA/MS.
OBSERVED AND MODEL FORECAST SOUNDINGS SUGGEST THAT SBCAPE MAY REACH
1000 J/KG ALONG AND S OF THE WARM FRONT...THOUGH LARGER VALUES
APPEAR UNLIKELY GIVEN THE EFFECTS OF CLOUDS AND RATHER MODEST MID
LEVEL LAPSE RATES.

VERTICAL SHEAR WILL REMAIN STRONGEST ALONG AND N OF THE WARM FRONT
AND IN CLOSER PROXIMITY TO THE MID LEVEL LOW ACROSS LA/MS
TODAY...SPREADING EWD INTO AL TONIGHT. INLAND PROGRESS OF THE WARM
SECTOR WILL CONTINUE TO MODULATE THE SEVERE STORM THREAT THROUGH
TONIGHT...WITH THE MORE PROBABLE AREAS REMAINING CLOSER TO THE COAST
ACROSS SW AL AND THE WRN FL PANHANDLE. FORECAST HODOGRAPHS...IN THE
PRESENCE OF 500-1000 J/KG MUCAPE AND MOIST PROFILES...APPEAR
SUPPORTIVE OF A FEW SUPERCELLS IN A NARROW CORRIDOR NEAR THE WARM
FRONT. WEAKER VERTICAL SHEAR IS EXPECTED FARTHER S IN THE OPEN WARM
SECTOR...AND MINIMAL INSTABILITY IS EXPECTED FARTHER N OF THE
BOUNDARY. THE PRIMARY SEVERE STORM THREATS WILL BE ISOLATED
DAMAGING WINDS AND A COUPLE OF TORNADOES BOTH TODAY WITH THE
PRE-FRONTAL CONVECTION...AND INTO TONIGHT WITH A BAND OF
THUNDERSTORMS ALONG THE COLD FRONT.

.THOMPSON/GRAMS.. 11/25/2007

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