ZCZC SPCSWOMCD ALL
ACUS11 KWNS 290425 
SPC MCD 290425 
ALZ000-MSZ000-ARZ000-LAZ000-290630-

Mesoscale Discussion 1912
NWS Storm Prediction Center Norman OK
1025 PM CST Wed Dec 28 2016

Areas affected...southeastern AR...northern LA...north-central
MS...and west-central AL

Concerning...Severe potential...Watch unlikely 

Valid 290425Z - 290630Z

Probability of Watch Issuance...20 percent

SUMMARY...An isolated wind-damage threat may develop over the next
several hours with an intensifying squall line located along an
east-southeastward moving cold front as it pushes through AR, MS,
and into AL overnight.  The coverage of severe is not expected to
warrant a severe thunderstorm watch.

DISCUSSION...Radar mosaic and MRMS CAPPI 9-km imagery show an
organizing band of storms over southeastern AR.  04 UTC surface
analysis indicates a cold front is co-located with the storms and
the frontal lift appears to be partially responsible for the
development of storms in combination with a shortwave trough
glancing the region as it moves eastward across the Ozarks.  It is
important to note this developing thunderstorm band is currently
moving into a warm frontal zone and an area of richer low-level
moisture with surface dewpoints in the lower 60s deg F.  As a result
of both cool H5 temperatures around -14 deg C yielding H7-H5 lapse
rates around 7.5 deg C/km and a slight uptick in moisture, 500-1000
J/kg MUCAPE is evident.  The 2-km deep moist layer depicted in
forecast soundings suggests surface cooling owing to the loss of
daytime heating will be thwarted by weak low-level moist/warm
advection.  The strong shear profile will act to organize cold pools
and potential small-scale bowing segments.  Yet, despite some
favorable factors for an organized squall line, weak 0-2 km lapse
rates less than 5 deg C/km will be less than ideal for momentum
transfer.  Nonetheless, an isolated risk for wind damage may develop
as the squall line continues to mature as it moves east-southeast
across southeastern AR and into MS tonight.

..Smith/Hart.. 12/29/2016

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BMX...MOB...MEG...JAN...LZK...SHV...

LAT...LON   33199303 33699194 34238971 33998808 33188784 32288843
            32069239 32529307 33199303 

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