Saturday, November 26, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261250
SWODY1
SPC AC 261248

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0648 AM CST SAT NOV 26 2011

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SE TX TO THE LWR MS VLY...

...SYNOPSIS...
PATTERN WILL FURTHER AMPLIFY OVER THE LWR 48 THIS PERIOD AS
CONTINUED PHASING OF SHORTWAVE IMPULSES OVER THE PLAINS RESULTS IN A
NARROW...FULL LATITUDE TROUGH FROM LK SUPERIOR TO E TX BY 12Z SUN.
AT THE SFC...THE UPR LVL CHANGES SHOULD FOSTER INTENSIFICATION OF
EXISTING COLD FRONTAL ZONE NOW EXTENDING FROM THE CNTRL IA TO N TX.
THE FRONT SHOULD REACH A JBR/MLU/LFT LINE BY THIS EVE...AND THE
MS-AL BORDER BY 12Z SUN.

...SE TX/LWR MS VLY TODAY/TNGT...
PREFRONTAL CONFLUENCE AXIS...MARKED BY LEADING EDGE OF ELEVATED
CONVECTIVE BAND NOW PRESENT FROM FAR ERN OK SSW ACROSS THE TX GULF
CSTL PLN...SHOULD SERVE AS THE MAIN FOCUS FOR POTENTIAL TSTM
DEVELOPMENT LATER TODAY AS THAT FEATURE IS OVERTAKEN BY PACIFIC COLD
FRONT NOW OVER CNTRL TX. OTHER STORMS MAY FORM FARTHER E...IN ZONE
OF LOW LVL CONFLUENCE LIKELY TO DEVELOP OVER ERN LA...MS...AND THE N
CNTRL GULF OF MEXICO IN RESPONSE TO VEERING OF LWR TROPOSPHERIC FLOW
WELL AHEAD OF THE EVOLVING UPR TROUGH.

COMBINATION OF MODEST SFC HEATING AND PERSISTENT LOW LVL MOISTURE
INFLOW /WITH PW RISING TO AOA 1.50 INCHES/ COULD SUPPORT POTENTIALLY
STRONG STORMS OVER SE TX AND THE LWR MS VLY LATER TODAY AND
TNGT...GIVEN PRESENCE OF 35-40 KT SSWLY DEEP SHEAR AND INCREASING
UPR DIVERGENCE IN SE PART OF AMPLIFYING UPR TROUGH.

WEAK MID LVL LAPSE RATES SHOULD MINIMIZE OVERALL INTENSITY AND
COVERAGE OF SVR THREAT. BUT SETUP COULD YIELD A BROKEN BAND OF
STORMS WITH EMBEDDED SUPERCELLS AND LEWPS THAT POSE A THREAT FOR
DMGG WIND AND POSSIBLY ISOLD TORNADOES...ESPECIALLY FROM SE TX ONTO
LA THIS AFTN AND EVE. A CONDITIONAL THREAT FOR TORNADOES ALSO WILL
EXIST WITH ANY MORE SEMI-DISCRETE STRUCTURES ABLE TO DEVELOP ALONG
LOW LVL CONFLUENCE FARTHER EAST ACROSS ERN LA...WRN AND SRN
MS...AND THE CNTRL GULF CST THROUGH EARLY SUN. NEWD PROGRESSION OF
ORGANIZED SVR THREAT SHOULD BE LIMITED BY WEAKER BUOYANCY OVER
NRN/ERN MS AND MOST OF AL.

..CORFIDI/LEITMAN.. 11/26/2011

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