[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 112201
SWOMCD
SPC MCD 112200
TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-112330-

MESOSCALE DISCUSSION 2159
NWS STORM PREDICTION CENTER NORMAN OK
0500 PM CDT SUN SEP 11 2011

AREAS AFFECTED...MIDDLE/WRN TN...CNTRL/NRN MS...PARTS OF CNTRL/NRN
AL...NERN LA...EXTREME SERN AR

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 112200Z - 112330Z

A FEW STORMS COULD PRODUCE STRONG WIND GUSTS INTO EARLY EVENING.
WITH ONLY A MINIMAL SVR THREAT...THE ISSUANCE OF A WW IS UNLIKELY.

LATE AFTERNOON MESOANALYSIS DEPICTS A SFC TROUGH AXIS EXTENDING
ACROSS THE MID-SOUTH INTO THE LOWER MS VALLEY. THIS FEATURE EXHIBITS
CHARACTERISTICS OF A DRYLINE NEAR AND SOUTH OF THE GREENVILLE MS
AREA...WHERE IT SEPARATES THE HOTTER/DEEPLY MIXED BOUNDARY LAYER TO
THE WEST FROM MODESTLY RICHER LOW-LEVEL MOISTURE TO THE EAST. THIS
MOISTURE...SUPPORTING MLCAPE VALUES OF 1000-1500 J/KG...WILL COMBINE
WITH SUFFICIENT SFC CONVERGENCE TO SUPPORT ISOLATED TO SCATTERED
THUNDERSTORMS INTO EARLY EVENING. THE GREATEST CONVECTIVE COVERAGE
IS ANTICIPATED ALONG AND NORTH OF THE HIGHWAY 82 CORRIDOR...WHERE
ASCENT OFFERED BY TWO SUBTLE MID-LEVEL IMPULSES PIVOTING AROUND THE
LARGER-SCALE PV MAX WILL AUGMENT DIURNALLY ENHANCED BOUNDARY-LAYER
CIRCULATIONS AND SFC CONVERGENCE ALONG THE TROUGH/DRYLINE. FARTHER
SOUTH...CONVECTIVE COVERAGE WILL BE MORE SUPPRESSED TOWARD
INTERSTATE 20...AS AMPLE DRY AIR ALOFT WRAPS AROUND THE SRN FRINGES
OF THE PV MAX.

ENHANCED MID/UPPER-LEVEL FLOW IN ASSOCIATION WITH A
CYCLONICALLY-CURVED UPPER-LEVEL SPEED MAX OVER THE AREA IS
SUPPORTING 25-30 KT OF EFFECTIVE BULK SHEAR SOUTH OF HIGHWAY
82...WITH WEAKER MID-LEVEL FLOW/VERTICAL SHEAR FARTHER NORTH. AS
SUCH...A FEW MULTICELLULAR CLUSTERS WILL BE POSSIBLE ACROSS PARTS OF
CNTRL/NRN MS AND CNTRL AL...WITH MORE PULSE CONVECTION ELSEWHERE.
STRONG WIND GUSTS AND SMALL HAIL WILL BE POSSIBLE WITH THE
STRONGEST/MOST PERSISTENT STORMS UNTIL AFTER 01Z...WHEN DIABATIC
COOLING COMMENCES. WHILE AN ISOLATED THREAT FOR A DMGG WIND GUST OR
MARGINALLY SVR HAIL CANNOT BE RULED OUT...THE LACK OF STRONGER
FORCING FOR ASCENT / GREATER INSTABILITY IS EXPECTED TO MITIGATE THE
OVERALL SVR THREAT.

..COHEN.. 09/11/2011

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

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

LAT...LON   35138574 33148704 31659072 32219187 33549095 36018841
            36418627 35138574


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