[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 070205
SWOMCD
SPC MCD 070204
KYZ000-INZ000-TNZ000-ILZ000-MOZ000-070300-

Mesoscale Discussion 1997
NWS Storm Prediction Center Norman OK
0804 PM CST Tue Dec 06 2022

Areas affected...Northwest Tennessee into northern Kentucky

Concerning...Severe potential...Watch unlikely

Valid 070204Z - 070300Z

Probability of Watch Issuance...20 percent

SUMMARY...A severe wind and weak tornado threat may emerge over the
next 1-2 hours across northwest Tennessee and into western/northern
Kentucky. However, this threat will be conditional on establishing
convection rooted in the boundary layer, which remains uncertain.
Regardless, the severe threat will remain too limited overall to
warrant watch issuance.

DISCUSSION...A gradual uptick in convection has been noted in IR
imagery and echo-top data across parts of northwest TN into western
and northern KY over the past hour as lift associated with a weak
upper-level impulse overspreads a warm frontal zone draped over the
mid-MS and lower OH River Valleys. Thus far, the north/northeasterly
propagation vectors of the stronger cells (including a supercell
near Louisville, KY) along the frontal zone suggest this convection
is most likely elevated in nature. However, latest RAP forecast
soundings and mesoanalysis estimates suggest MLCAPE may be as high
as 500 J/kg along and to the south of the boundary across northwest
TN/southwest KY. Convection that can become rooted in the boundary
layer within this zone may access the 200-300 J/kg 0-1 km SRH
observed in regional VWP observations and take on better structure.

If this occurs, the potential for damaging winds, and perhaps a
tornado, will increase; however, mixed-layer buoyancy is expected to
diminish over the next few hours amid gradual nocturnal cooling.
Consequently, it is unclear if the deepening convection will
intensify sufficiently to realize the low-level wind shear and pose
a severe threat prior to the loss of adequate near-surface buoyancy.
The ongoing organized cells near the Louisville, KY area are quickly
propagating into a cooler air mass and away from the better MLCAPE,
which should limit their access to boundary-layer buoyancy.

..Moore/Edwards.. 12/07/2022

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

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

LAT...LON   36528945 37108883 37538793 38108680 38638567 38718493
            38558425 38128419 37538459 36888564 36658612 36388684
            36148735 35928798 35788853 35758929 36008966 36528945
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