[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 042322
SWOMCD
SPC MCD 042321
TNZ000-GAZ000-ALZ000-KYZ000-MOZ000-ARZ000-050015-

Mesoscale Discussion 0535
NWS Storm Prediction Center Norman OK
0621 PM CDT Mon May 04 2020

Areas affected...Portions of central into middle Tennessee...far
northeast Alabama...far northwest Georgia

Concerning...Severe potential...Watch likely

Valid 042321Z - 050015Z

Probability of Watch Issuance...95 percent

SUMMARY...Organized quasi-linear convection continues to grow
upscale, with relatively deep moisture and instability increasing
ahead of the cluster. Bow echo development is possible with this
convection, with damaging winds likely. Large hail will also be a
concern, and given modest backing of the surface flow, a brief
tornado cannot be ruled out. A downstream WW issuance will likely be
needed.

DISCUSSION...Strong linear segments, embedded within a larger region
of convection, have produced 1-1.5 inch hail within the past couple
of hours. KNQA WSR-88D data also suggests that some of these storm
cores are hail/graupel laden, with up to 60 dBZ echoes noted over
the -20C layer. In addition, latest RAP forecast soundings indicate
a relatively dry, deep layer extending from 800-600 mb, suggesting
that rapid cold pool development and expansion may accompany the
aforementioned convection given adequate evaporative cooling of
rainwater, supported by mid-level melting of frozen graupel/hail.

Deep 925-850 mb moisture and steep mid-level lapse rates are both
advecting northeastward ahead of the convection. Additional
intensification of updrafts, and further evaporative cooling given
the previously mentioned accompanying dry mid-level layer, will both
serve to increase the damaging wind and large hail threat over the
next few hours, as supported by the latest high-resolution model
guidance. Given backed surface winds across portions of Middle
Tennessee, a tornado or two may also occur. Severe potential is
expected to continue downstream of WW 0164 as storm mergers and
upscale growth continues, with a WW issuance expected shortly.

..Squitieri.. 05/04/2020

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

ATTN...WFO...MRX...FFC...OHX...HUN...PAH...MEG...

LAT...LON   35689022 36049035 36379008 36668961 36798930 36698862
            36568790 35798576 35238462 34868472 34698485 34558546
            34528609 34678700 34978787 35348961 35689022
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