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000
ACUS11 KWNS 051643
SWOMCD
SPC MCD 051643
ALZ000-TNZ000-MSZ000-LAZ000-ARZ000-051845-

MESOSCALE DISCUSSION 2057
NWS STORM PREDICTION CENTER NORMAN OK
1043 AM CST THU DEC 05 2013

AREAS AFFECTED...NERN LA / CNTRL MS / NWRN AL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 051643Z - 051845Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A CONDITIONAL THREAT FOR ISOLD DMGG WINDS AND A TORNADO OR
TWO APPEARS TO BE INCREASING ACROSS PORTIONS OF THE LOWER MS RIVER
VALLEY AND EVENTUALLY SPREADING NEWD INTO NWRN PORTIONS OF AL.
STORMS ARE EXPECTED TO DEVELOP/INCREASE IN INTENSITY DURING THE
17-22Z TIMEFRAME.

DISCUSSION...LATEST SUBJECTIVE SURFACE ANALYSIS SHOWS UPPER 60S TO
NEAR 70 DEG DEWPOINTS SPREADING NWD EITHER SIDE OF THE LA/MS BORDER
WITH UPPER 60S /AS OF 16Z/ ADVECTING NEWD INTO NERN MS AND NWRN AL.
VISIBLE SATELLITE IMAGERY DURING THE PAST FEW HOURS SHOWS THINNING
CLOUD COVER OVER CNTRL MS INTO W-CNTRL AL AS TEMPS RISE INTO THE
LOWER 70S AND THIS HEATING IS CONTRIBUTING TO FURTHER
DESTABILIZATION.  OF PARTICULAR NOTE...THE 12Z RUN OF THE RAP MODEL
UNDER-FORECASTED SURFACE DEWPOINTS THIS MORNING /ROUGHLY 2 DEG F/
AND MAGNITUDE OF LOW-LEVEL SHEAR /COMPARED TO THE 12Z JAN RAOB/.
DESPITE SOMEWHAT MEAGER LAPSE RATES...MODIFYING THE 12Z JAN RAOB FOR
MID 70S TEMP/70 DEWPOINT BOOSTS MLCAPE TO AROUND 800 J/KG AND
REDUCES SBCINH WITHIN A VERY MOIST LOW LEVEL AIRMASS.  MORE THAN
ADEQUATE SHEAR PROFILES ALONG WITH CONTINUED LOW-LEVEL CONFLUENT
REGIME AHEAD OF THE SEWD-MOVING COLD FRONT WILL LEND SUPPORT FOR
MAINLY DIURNALLY-PEAKING STORMS AND AN INCREASED PROPENSITY FOR
GRADUAL STORM INTENSIFICATION AND ISOLD LOW-LEVEL SUPERCELL
ROTATION--PERHAPS CAPABLE OF A DMGG WIND GUST OR TORNADO WITH THE
LONGER-LIVED CIRCULATIONS.

..SMITH/CORFIDI.. 12/05/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...

LAT...LON   32689166 34398912 35098782 34938687 34538677 33398812
            31889039 31789176 32689166