RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Fri Nov 21 13:02:01 UTC 2025.
No Mesoscale Discussions are in effect as of Fri Nov 21 13:02:01 UTC 2025.
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0657 AM CST Fri Nov 21 2025
Valid 211300Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
MISSISSIPPI/ALABAMA INTO TENNESSEE AND SOUTHEAST KENTUCKY....
...SUMMARY...
Isolated strong to severe storms are possible later today into
tonight across parts of Mississippi and Tennessee into western and
northern Alabama.
...MS/AL/TN/KY...
Early morning water vapor imagery shows broad west-southwesterly
flow aloft extending from the southern Plains into the southeast
states. A southern-stream shortwave trough is noted over LA/AR,
which will traverse across the mid-South and TN Valley today.
Multiple areas of precipitation will be present along/ahead of this
feature, with forecast soundings showing weak-but-sufficient CAPE
for a few thunderstorm clusters. Mid-level lapse rates are weak,
suggesting most updrafts will struggle to intensify. However,
forecast hodographs show strong low-level shear today from eastern
MS across parts of AL/Middle TN and southeast KY. This could be
enough for one or two rotating cells capable of a tornado or
damaging wind event. The overall threat appears marginal at this
time.
The primary surface cold front will move into this region after dark
tonight, with another round of showers and thunderstorms ahead of
the front. Low-level winds are expected to somewhat veer by this
time, reducing low-level shear. Nevertheless, a low risk of a
tornado or two and/or gusty winds will continue.
...Southern CA...
An upper low is centered off the coast of southern CA today, with
scattered showers and isolated thunderstorms ongoing. This trend
will continue through the day, with some risk of a few robust
thunderstorms affecting coastal areas. Onshore instability and
low-level shear are expected to remain weak, suggesting organized
severe storms are unlikely.
..Hart/Broyles.. 11/21/2025
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SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 AM CST Fri Nov 21 2025
Valid 231200Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
TEXAS TO THE RIO GRANDE...
...SUMMARY...
Isolated severe thunderstorms are possible across portions of
central Texas to the Rio Grande on Sunday. Large hail and damaging
wind gusts will be the primary threats.
...Synopsis...
A closed mid-level low across the Southwest will become an open wave
as it moves into the Plains on Sunday. Weak surface troughing is
forecast to develop across the High Plains during the day.
Strengthening southerly flow east of this surface trough will bring
rich moisture northward across central Texas as a warm front lifts
northward.
...Central Texas to the Rio Grande...
Strengthening low-level flow will continue to destabilize the
boundary layer through the day as a warm front lifts north. As
isentropic ascent increases during the afternoon/evening, widespread
thunderstorm activity is anticipated along the warm front and also
along the cold front/dryline. Moderate instability and strong shear
will support the potential for mostly elevated supercells capable of
isolated large hail. As storms grow upscale, the threat for damaging
wind gusts will increase during the late evening and into the
overnight period. Initially, expect convection to be elevated, but
it may eventually become more surface based as storms advance into
the warm sector. Low-level lapse rates will be very weak (3-4 C/km)
which should keep any tornado threat isolated. However, given the
strong low-level shear, an isolated tornado cannot be ruled out.
..Bentley.. 11/21/2025
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0351 AM CST Fri Nov 21 2025
Valid 241200Z - 291200Z
...DISCUSSION...
As a mid-level trough deamplifies and moves from the central Plains
to the Midwest on D4/Monday, low-level moisture will advect
northward across eastern Texas, Louisiana, and southern Arkansas.
Some filtered heating should result in moderate instability by early
afternoon with moderate to strong shear. Morning thunderstorms will
likely have a stabilizing effect on the northern extent, but south
of this activity, a relatively more favorable zone for supercells
may exist on Monday afternoon. Relatively weak lapse rates are the
primary limiting factor to severe weather probabilities at this
time.
On D5/Tuesday, the surface front will stall across Louisiana and
Mississippi with weak to moderate instability to its south. Forcing
will remain somewhat nebulous, but given persistent moderate shear,
a few stronger storms will be possible from eastern Louisiana to
northern Alabama.
D6/Wednesday and beyond will feature a strong area of high pressure
across much of the eastern CONUS. This will push 60F dewpoints into
the Gulf/Atlantic and bring an end to any severe weather threat and
potentially any thunderstorm threat east of the Rockies for the
remainder of the week.
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