[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 061933
SWOMCD
SPC MCD 061933
KYZ000-INZ000-TNZ000-ILZ000-062200-

Mesoscale Discussion 0208
NWS Storm Prediction Center Norman OK
0133 PM CST Sun Mar 06 2022

Areas affected...western Tennessee and southwestern Kentucky

Concerning...Severe potential...Watch possible

Valid 061933Z - 062200Z

Probability of Watch Issuance...40 percent

SUMMARY...Strong to severe storms are possible this afternoon and
evening along and south of a quasi-stationary front across parts of
western TN and KY. Supercells with the potential for damaging wind
gusts, hail and perhaps a tornado or two will be possible.
Uncertainty exists on the eastern extent of any severe threat.

DISCUSSION...Visible satellite imagery and surface obs showed a
complex convective scenario unfolding across parts of the Tennessee
and lower Ohio Valleys this afternoon. To the south of a
quasi-stationary front near the Ohio River, scattered thunderstorms
and deepening cumulus towers were ongoing within a weak warm
advection regime across parts of western KY and northwestern TN.
Likely rooted above the immediate surface, continued warming
temperatures from low-level advection and clearing skies farther
south should result in gradual surface-based destabilization in
proximity to these storms over the next few hours. With low 60s F
surface dewpoints already in place, model soundings show potentially
500 to 1250 J/kg of MLCAPE available across western TN and
southwestern KY. This should be sufficient to support ongoing storms
with a gradual increase in intensity possible over the next few
hours. The mostly free warm sector may also support new storm
development farther south and west.

Primary uncertainty remains the weak forcing for ascent this
afternoon. Driven by isentropic lift and local heating away from the
main synoptic forcing over the southern High Plains, storm evolution
is expected to be gradual. Remaining MLCINH is negligible, and
hi-res guidance does suggest additional stronger development is
possible across western TN between 20 and 22z. Wind fields aloft are
robust, with 0-6 km shear of 40-60 kts across much of the warm
sector. This should support storm organization with a mixed mode of
supercells and line segments. Damaging wind gusts and some hail are
possible given the favorable buoyancy and shear for organized
storms. Low-level shear is not as strong from weakly veering surface
flow near the boundary. However, some curvature and the potential
for supercells suggests a tornado or two will remain possible.

The severe threat may extend farther north and east with time across
central KY and TN. However, current observations show deeper surface
moisture has yet to reach that far east given the mostly weak
low-level advection. While some increase in buoyancy is possible
over the next few hours and this evening with an increasing
low-level jet, it remains unclear if storms will present much of a
severe threat east, tonight.

..Lyons/Hart.. 03/06/2022

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

ATTN...WFO...ILN...LMK...OHX...PAH...MEG...

LAT...LON   37258845 37698751 37978676 38478581 38588526 38568483
            38468451 38238434 37418475 37178503 36798563 36168676
            35968737 35808805 35688902 35728914 35848934 36078943
            36538921 37258845
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