Severe Storm Outlook Narrative (AC)
Issued by NWS

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448
ACUS11 KWNS 292247
SWOMCD
SPC MCD 292246
ALZ000-300115-

MESOSCALE DISCUSSION 1842
NWS STORM PREDICTION CENTER NORMAN OK
0446 PM CST TUE NOV 29 2016

AREAS AFFECTED...PORTIONS OF WESTERN AL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 292246Z - 300115Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE AREA IS BEING MONITORED FOR ONGOING SUPERCELLS IN MS
THAT COULD BEGIN TO SPREAD INTO THE LOCAL AREA WITHIN THE NEXT FEW
HOURS. THERE IS SOME QUESTION WITH REGARD TO THEIR SUSTAINABILITY...
THOUGH THE POTENTIAL DOES EXIST FOR A SEVERE-THUNDERSTORM/TORNADO
RISK TO EVOLVE THIS EVENING. THE AREA WILL CONTINUE TO BE MONITORED
FOR POSSIBLE TORNADO WATCH ISSUANCE.

DISCUSSION...ONGOING SUPERCELL THUNDERSTORMS IN MS...ADDRESSED IN
RECENTLY ISSUED MCD 1841...ARE SPREADING NORTHEASTWARD AND
EAST-NORTHEASTWARD. THE AIR MASS DOWNSHEAR INTO AL IS CHARACTERIZED
BY MIDDLE 60S DEWPOINTS SUPPORTING MLCAPE AROUND 500-1000 J/KG...
LITTLE MLCINH...AND 50-60 KT OF EFFECTIVE SHEAR. IF STORMS IN MS WERE
TO BE SUSTAINED EASTWARD INTO WESTERN AL...THE POTENTIAL FOR ALL
SEVERE HAZARDS COULD SPREAD INTO THE AREA...INCLUDING A TORNADO
RISK -- AIDED BY EFFECTIVE SRH AROUND 300-400 M2/S2. HOWEVER...THE
OVERALL LIMITED DEGREE OF LARGE-SCALE ASCENT CASTS CONSIDERABLE
DOUBT ON THEIR SUSTAINABILITY. WHILE PERTURBATION-PRESSURE GRADIENTS
ASSOCIATED WITH ALREADY-ESTABLISHED ROTATING UPDRAFTS COULD
ENCOURAGE THEIR SUSTENANCE INTO THE AREA -- ESPECIALLY GIVEN LOW
MLCINH -- THE LACK OF STRONGER BUOYANCY/ASCENT COULD BE NEGATING
FACTORS. AS SUCH...CONVECTIVE/ENVIRONMENTAL TRENDS WILL CONTINUE TO
BE MONITORED.

..COHEN/HART.. 11/29/2016

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

ATTN...WFO...BMX...

LAT...LON   33438823 34168806 34108736 33538723 32828729 32618792
            32768827 33438823




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