[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 171911
SWOMCD
SPC MCD 171911
KYZ000-TNZ000-ALZ000-MSZ000-172115-

Mesoscale Discussion 0144
NWS Storm Prediction Center Norman OK
0111 PM CST Thu Feb 17 2022

Areas affected...Parts of western and middle Tennessee...adjacent
south central Kentucky and northwestern Alabama

Concerning...Severe potential...Watch possible

Valid 171911Z - 172115Z

Probability of Watch Issuance...60 percent

SUMMARY...A narrow evolving line of heavier showers and embedded
thunderstorms may overspread the region through mid to late
afternoon, with at least some potential for brief strong to locally
damaging wind gusts.

DISCUSSION...A narrow line of enhanced convection, with embedded
thunderstorms, has gradually evolved, perhaps aided by frontogenetic
forcing, and appears likely to advance rapidly east-northeastward
across the Mid South through 22-00Z.  This is nearly coincident with
an intensifying lower/mid tropospheric speed maximum, including
speeds of 70-90+ kt in the 850-500 mb layer, overspreading the lower
Ohio/Tennessee Valley vicinity.

Ahead of this activity, persistent preceding rainfall appears to
have contributed to a deep tropospheric layer of moist adiabatic
lapse rates, with model forecast soundings suggesting little change
prior to the arrival of the convective line.  Some model output
indicate a more stable near-surface layer persisting as well, but
the Rapid Refresh forecast soundings indicate lapse rates may trend
at least closer to moist adiabatic just ahead of the line.
Regardless, this seems likely to minimize the potential for vigorous
downdrafts.  Furthermore, forecast soundings also suggest that
low-level hodographs will trend more linear with the arrival of the
line.

Given these trends, the evolution of an appreciable severe weather
threat is uncertain.  However, due to the strength of the wind
fields just above the surface, downward mixing of potentially
damaging wind gusts might not be out of the question, particularly
aided by the narrow heavier rain band.

..Kerr/Grams.. 02/17/2022

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

ATTN...WFO...LMK...OHX...HUN...PAH...MEG...

LAT...LON   35838964 36488881 37428594 36968530 34588776 35108868
            35068973 35838964
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