Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 271858
SPC MCD 271858

Mesoscale Discussion 0345
NWS Storm Prediction Center Norman OK
0158 PM CDT Mon Mar 27 2017

Areas affected...Middle Tennessee...Western and Central
Kentucky...Far Southern Indiana

Concerning...Severe potential...Watch likely

Valid 271858Z - 272100Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat is likely to develop across west-central
Kentucky and middle Tennessee over the next couple of hours. Wind
damage and isolated large hail will accompany the stronger
thunderstorms as cells move northeastward out of WW 89. New WW
issuance is probable across parts of central Kentucky and middle
Tennessee by 20Z.

DISCUSSION...The latest radar imagery shows several clusters of
strong to severe thunderstorms ongoing from northern Mississippi
northward across western Tennessee into southwestern Kentucky. These
storm clusters are located along the leading edge of large-scale
ascent associated with a shortwave trough moving into the mid
Mississippi Valley. At the surface, a corridor of low-level moisture
is present across middle Tennessee extending northward into
west-central Kentucky where surface dewpoints are in the upper 50s
to near 60 F. Due to surface heating, moderate instability is now in
place over the southern two-thirds of the MCD area with MLCAPE
values estimated at 1000 to 1500 J/kg by the RAP. In addition to the
instability, moderate deep-layer shear is present with the Nashville
WSR-88D VWP showing 40 kt of 0-6 km shear and the Louisville WSR-88D
VWP up to almost 45 kt. This shear environment should support severe
storm development. Cells that remain discrete will have the
opportunity to become supercells and should be accompanied by large
hail and wind damage. A tornado or two will be possible with
supercells especially across middle Tennessee where more instability
is present and low-level shear is adequate for low-level storm
rotation. Cell clusters that can organize into short line-segments
should be favored for a wind damage threat but hail could also occur
with the more intense parts of the line.

..Broyles.. 03/27/2017

...Please see for graphic product...


LAT...LON   37938515 38308686 37968774 37198805 36658816 35898826
            35068806 34818699 35078560 35998532 37938515 is the U.S. government's official web portal to all federal, state and local government web resources and services.