Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 272300
SPC MCD 272259
Mesoscale Discussion 0349
NWS Storm Prediction Center Norman OK
0559 PM CDT Mon Mar 27 2017
Areas affected...Parts of western/middle Tennessee and adjacent
Concerning...Severe Thunderstorm Watch 89...91...
Valid 272259Z - 280030Z
The severe weather threat for Severe Thunderstorm Watch 89, 91
SUMMARY...The risk mainly for severe hail and strong surface gusts
is expected to continue with storms overspreading middle Tennessee
into/through the 7-10 pm CDT time frame.
DISCUSSION...In the wake of generally weakening, loosely organized
convective development now spreading toward the central/southern
Appalachians, an area of enhanced low-level warm advection is
maintaining vigorous thunderstorm activity near/east of the
Interstate 40 corridor of western into middle Tennessee. Forcing
associated with the remnants of a compact mid-level closed low
likely is augmenting ascent and associated convection, which is
expected to continue to spread eastward across middle Tennessee
into/through the 00-03Z time frame.
Inflow of relatively moist low-level air into the vicinity of this
activity, beneath a lingering area of steep mid-level lapse rates is
probably contributing to moderately large CAPE. This may be mostly
based above a relatively stable surface-based air mass, but, in the
presence of strong vertical shear, supercells will remain possible,
with upscale growth into a small organizing convective system
possible through mid/late evening. While an additional isolated
tornado may not be out of the question, the risk for severe hail and
strong surface gusts seems more prominent.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 36648735 36848646 36658534 35898499 34978634 34768747
34928859 35138904 35948841 36648735