Severe Weather Event Thanksgiving Week.

[srainhoutx]

MESOSCALE DISCUSSION 2081
NWS STORM PREDICTION CENTER NORMAN OK
0944 AM CST THU NOV 25 2010

AREAS AFFECTED...ERN AR...WRN TN...NWRN MS

CONCERNING...OUTLOOK UPGRADE

VALID 251544Z - 251645Z

WE ARE PLANNING TO REINTRODUCE THE SLIGHT RISK WITH THE 1630Z UPDATE
FOR A THREAT OF ISOLATED DAMAGING WIND AND ISOLATED TORNADOES.

THIS MORNING A COLD FRONT EXTENDS FROM ERN IL TO SERN MO...NWRN AR
AND NERN THROUGH CNTRL TX ALONG WITH A PRE-FRONTAL TROUGH FROM SERN
MO...CNTRL AR INTO NERN TX. MORNING RAOB DATA FROM LITTLE ROCK SHOWS
A MARGINAL THERMODYNAMIC ENVIRONMENT WITH WEAK CAPE AND LAPSE RATES
AOB 6 C/KM. HOWEVER...NO CONVECTIVE INHIBITION WAS INDICATED AND IF
TEMPERATURES RISE TO THE MID 70S MLCAPE WILL LIKELY INCREASE TO
BETWEEN 500-800 J/KT. VISIBLE IMAGERY INDICATES A ZONE OF MIXING AND
PARTIAL CLEARING SHIFTING NEWD THROUGH NRN LA. THIS SUGGESTS AT
LEAST MODEST WARMING AND DESTABILIZATION OF THE BOUNDARY LAYER WILL
BE POSSIBLE AS FAR NORTH AS SRN AR DURING THE AFTERNOON. MODEL
CONSENSUS IS THAT SRN BRANCH OF THE LOW LEVEL JET NOW OVER ERN TX
WILL SHIFT NEWD THROUGH THE LOWER MS VALLEY TODAY IN ASSOCIATION
WITH UPPER JET ENTRANCE REGION. GIVEN STRONG SHEAR PROFILES ALREADY
IN PLACE...A SLOW AND MODEST BOUNDARY LAYER DESTABILIZATION MAY HELP
STORMS DEVELOPING ALONG LOW LEVEL JET AXIS TO GRADUALLY INTENSIFY
AND BECOME BETTER ORGANIZED AS SUPERCELLS AND BOWING SEGMENTS.

..DIAL.. 11/25/2010