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000
ACUS11 KWNS 191833
SWOMCD
SPC MCD 191833
NCZ000-VAZ000-SCZ000-TNZ000-GAZ000-192030-

Mesoscale Discussion 0494
NWS Storm Prediction Center Norman OK
0133 PM CDT Fri Apr 19 2024

Areas affected...portions of the Tennessee Valley into the
Mid-Atlantic

Concerning...Severe potential...Watch unlikely

Valid 191833Z - 192030Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm development is anticipated in the next couple
of hours across parts of the southern Appalachians. These storms
should gradually intensify through the mid/late afternoon, and may
pose a severe hail/wind threat across parts of far eastern Tennessee
and adjacent portions of Virginia and the Carolinas. The coverage of
strong/severe storms should be sufficiently limited to preclude
watch issuance.

DISCUSSION...A gradually deepening cumulus field has been tracked in
GOES visible/IR imagery and regional radars over the past 60
minutes. Lingering inhibition has precluded deeper convection so
far, but continued daytime heating along with combined forcing for
ascent along an approaching cold front and orographic lift within
the southern Appalachians should foster more robust thunderstorms in
the coming hours. Despite weak low-level winds, 30-40 knot flow
aloft is supporting effective bulk shear values near 30-35 knots,
which should be sufficient for some organization of deeper cells
that may pose a large hail risk (most likely between 0.75 to 1.25
inch in diameter). Additionally, heating of a somewhat dry air mass
downstream across the Carolinas (where temperatures are climbing
into the low 80s under clearing skies) should steepen low-level
lapse rates by late afternoon to around 8 C/km. This may favor
outflow-driven storms with a tendency for upscale growth into
clusters and the potential for strong to severe gusts.

..Moore/Smith.. 04/19/2024

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

ATTN...WFO...RAH...RNK...RLX...CAE...GSP...MRX...FFC...

LAT...LON   36658012 36187981 35217999 34728071 34498146 34518259
            34618339 34908423 35268452 35668427 36978244 37068172
            36968086 36658012