948
ACUS01 KWNS 211944
SWODY1
SPC AC 211942

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0142 PM CST Fri Nov 21 2025

Valid 212000Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
MS/AL/TN/KY...

...SUMMARY...
Isolated strong to severe storms are possible today and tonight
across parts of Mississippi and Tennessee into western and northern
Alabama and possibly southern Kentucky.

...20Z Update...
The Marginal Risk was trimmed slightly in northern/central MS, where
a combination of relatively weaker large-scale forcing for ascent
and poor deep-layer lapse rates/modest buoyancy (see SHV 18Z
sounding) should limit the severe-risk compared to areas farther
north tonight. Elsewhere, widely scattered thunderstorms are
evolving along a southeastward-moving cold front in southeast TX.
PBL destabilization ahead of the front has yielded moderate
surface-based buoyancy (per CRP 18Z sounding). While several warm
layers aloft and modest deep-layer shear (around 30 kt of effective
shear) should limit updraft intensity, a strong storm or two capable
of producing gusty winds cannot be entirely ruled out into this
evening.

..Weinman.. 11/21/2025

.PREV DISCUSSION... /ISSUED 1029 AM CST Fri Nov 21 2025/

...MS/AL/TN/KY...
A strengthening of deep-layer flow will occur regionally in tandem
with the eastward progression of a low-amplitude shortwave trough
from the Lower Missouri Valley toward the Lower Ohio River Valley
tonight, with height falls remaining limited south of the Tennessee
Valley.

The more organized/sustained scattered thunderstorms this afternoon
will probably remain focused within the warm conveyor from
south-central Mississippi into Alabama. On the south-southwest
periphery of these storms, there will be a gradual northeastward
expansion of the effective warm sector while destabilization will
still remain weaker with eastward extent. Mid-level lapse rates are
weak, suggesting most updrafts will struggle to intensify. However,
strong deep-layer shear and moderately strong low-level shear/SRH,
particularly within the aforementioned corridor, could support a
couple of rotating storms capable of a tornado or damaging wind.

The primary surface cold front will move into this region tonight,
with another round of showers and thunderstorms expected to uptick
this evening across the Mid-South including western Tennessee and
northern Mississippi. Low-level winds are expected to veer by this
time, reducing low-level shear/SRH. Nevertheless, a low risk of a
tornado and/or gusty winds will exist.

$$