RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1020 AM CST Thu Nov 27 2025
Valid 271630Z - 281200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorms are not forecast through tonight.
...Synopsis and Discussion...
A large-scale upper trough encompassing much of the central/eastern
CONUS will develop slowly eastward through the period. Isolated
thunderstorm potential today will generally remain limited to parts
of south FL and the Keys along/ahead of a southward-moving cold
front. 11/12Z soundings from XMR/TBW/KEY show southwesterly winds
strengthening with height at mid/upper levels. While sufficient
deep-layer shear may exist to support a stronger thunderstorm or two
this afternoon, especially along the Atlantic Coast in south FL, the
presence of poor mid-level lapse rates and weak low-level winds
should hinder the risk for organized severe thunderstorms over land.
Isolated lightning flashes may also occur with snow bands occurring
in western NY off of Lake Ontario.
..Gleason/Wendt.. 11/27/2025
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0139 PM CST Thu Nov 27 2025
Valid 272000Z - 281200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorms are not forecast through tonight.
...20z Update...
Only minor adjustments were made to the thunder line to account for
ongoing trends across the Florida peninsula. Otherwise, no
additional changes are needed. See previous discussion for more
information.
..Thornton.. 11/27/2025
.PREV DISCUSSION... /ISSUED 1020 AM CST Thu Nov 27 2025/
...Synopsis and Discussion...
A large-scale upper trough encompassing much of the central/eastern
CONUS will develop slowly eastward through the period. Isolated
thunderstorm potential today will generally remain limited to parts
of south FL and the Keys along/ahead of a southward-moving cold
front. 11/12Z soundings from XMR/TBW/KEY show southwesterly winds
strengthening with height at mid/upper levels. While sufficient
deep-layer shear may exist to support a stronger thunderstorm or two
this afternoon, especially along the Atlantic Coast in south FL, the
presence of poor mid-level lapse rates and weak low-level winds
should hinder the risk for organized severe thunderstorms over land.
Isolated lightning flashes may also occur with snow bands occurring
in western NY off of Lake Ontario.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1120 AM CST Thu Nov 27 2025
Valid 281200Z - 291200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few thunderstorms are possible over the southern Plains and lower
Missouri Valley Friday night into early Saturday morning. Severe
thunderstorms are not currently expected.
...Synopsis...
Mid-level ridging over the central US will shift eastward behind a
departing trough over the East. A second trough will deepen over the
Rockies encouraging lee cyclogenesis over the southern Plains
Friday. As the surface low deepens, modest low-level moisture will
advect northward with a 40-60 kt southerly low-level jet. Lift from
the approaching trough and an attendant cold front will support
isolated thunderstorms from the southern Plains to the lower MO
Valley late Friday into early Saturday.
...Southern Plains into the lower Missouri Valley...
Ahead of the lee low, strong low-level warm air advection will
transport middling surface moisture northward over parts of
central/north TX into southern OK ahead of the surging cold front.
In the wake of the prior frontal passage, a persistent surface
stable layer is likely to prevent substantial northward moisture
return over the southern Plains. However, cold mid-level
temperatures (H5 temps -24C) beneath the deepening upper trough will
likely support some elevated buoyancy development late Friday,
overnight into Saturday. Isolated thunderstorms are possible within
the boarder warm advection band. While generally weak, (~250-500
J/kg MUCAPE) sufficient destabilization and strong flow aloft could
support an occasional stronger storm capable of small hail from
northeast TX into eastern OK and the Ozarks. But, given the limited
thermodynamics, a sustained severe risk appears unlikely.
..Lyons.. 11/27/2025
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0130 PM CST Thu Nov 27 2025
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF
EASTERN TEXAS AND SOUTHWESTERN LOUISIANA...
...SUMMARY...
Isolated severe thunderstorms are possible across portions of
southeast Texas into western Louisiana Saturday afternoon or
evening.
...Synopsis...
The shortwave trough over the central Plains will move eastward as
mid-level westerly flow intensifies from the Plains to the MS Valley
and Midwest Saturday/Sunday. A surface low attendant to the trough
will move from OK/KS to the southern Great Lakes as a strong cold
front moves south from the Red River to the lower MS Valley.
Moisture return ahead of the front will support scattered
thunderstorms across eastern TX, the Sabine Valley and lower MS
valley through early morning Sunday.
...Southeast TX to western LA...
With southerly surface flow expected to develop ahead of the
deepening surface cyclone over the Plains Saturday, low-level
moisture advection should increase across coastal and southeast TX
into LA. A warm front will slowly lift northward, stalling over
southwest LA as it encounters a deep and cool air mass farther
north. Continued low-level warm air advection (despite ongoing
showers and remnant clouds) should allow for gradual destabilization
Saturday afternoon. While overall forcing for ascent appears weak as
the upper trough departs to the north, scattered thunderstorm
development appears probable, both within the low-level warm
advection regime and along the approaching cold front from the
Northwest. Given expected mid to upper 60s F dewpoints beneath 7-8
C/km mid-level lapse rates, around 1000 J/kg MLCAPE could support a
few stronger updrafts late Saturday through Sunday morning. Residual
westerly flow aloft may also favor some storm organization with
multicell lines or clusters and perhaps transient supercells capable
of damaging gusts and hail. This is most likely from the TX coastal
Plain to southwestern LA before the cold front moves offshore into
the Gulf.
..Lyons.. 11/27/2025
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