RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Mar 21 18:54:02 UTC 2026.
No Mesoscale Discussions are in effect as of Sat Mar 21 18:54:02 UTC 2026.
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat Mar 21 2026
Valid 211630Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN APPALACHIANS INTO THE CAROLINAS...
...SUMMARY...
Isolated strong to severe thunderstorms may produce marginally
severe hail and damaging winds this afternoon and evening from the
southern Appalachians into the Carolinas.
...Southern Appalachians into the Carolinas...
Recent satellite imagery shows a somewhat subtle and broad shortwave
trough progressing southeastward through the MS Valley, along the
far northeast periphery of the upper ridging covering much of the
Southwest and southern Plains. Limited low-level moisture precedes
this wave, with recent surface analysis sampling dewpoints ranging
from the upper 50s across much of AL to the mid 40s across much of
the Carolinas. Modest low-level moisture advection is anticipated
today ahead of this wave. However, this advection will be countered
by diurnal mixing, and the general expectation is for dewpoints to
be in the upper 40s/low 50s from eastern TN into the Carolinas as
the wave moves in the area this afternoon. Even with this limited
low-level moisture, cool mid-level temperatures and associated steep
mid-level lapse rates will support weak buoyancy and the potential
for isolated to widely scattered thunderstorms this afternoon and
early evening.
Large-scale ascent will be modest, supporting an initially more
cellular, loosely organized storm mode. This region will be on the
southern periphery of the stronger mid-level flow, likely resulting
in sufficient shear for organization within any deeper, more
persistent updrafts. As such, updrafts are expected to gradually
intensify as they move into the western and central Carolinas.
Marginally severe hail is possible with the strongest cores. A trend
towards a more linear/line segment mode is expected with time, and
persistent steep low-level lapse rates may support occasional strong
to damaging downdraft winds as well. The onset of nocturnal
boundary-layer stabilization should result in a decreasing severe
threat as the storms move into the coastal Carolinas.
..Mosier/Chalmers.. 03/21/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1223 PM CDT Sat Mar 21 2026
Valid 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO
VALLEY INTO THE NORTHERN MID ATLANTIC...
...SUMMARY...
Scattered strong to severe thunderstorms with large hail, damaging
wind gusts, and possibly some tornado threat are expected on Sunday
afternoon and evening across parts of the Ohio Valley into the
northern Mid Atlantic region.
...Synopsis...
A mid/upper-level shortwave trough is forecast to gradually amplify
on Sunday, as it moves from the northern Plains towards the Great
Lakes region. This amplification will occur within a broader
west-northwesterly flow regime, with relatively strong deep-layer
flow expected to eventually overspread the Ohio Valley and Mid
Atlantic regions. A cold front initially draped from the central
Plains into the Lower Great Lakes will move generally southeastward
through the period, as one or more frontal waves traverse the front
from the mid MS Valley into the Northeast and Mid Atlantic.
...Ohio Valley into parts of the Mid Atlantic...
A plume of relatively steep midlevel lapse rates will emanate out of
an anomalously hot and well-mixed regime across the Southwest and
central/southern Plains and overspread parts of the Ohio Valley on
Sunday. With favorable deep-layer flow/shear expected across the
Ohio Valley and Mid Atlantic, the primary uncertainty regarding the
magnitude of buoyancy and potential severe threat is low-level
moisture return. The partially modified nature of returning Gulf
moisture and a tendency for strong antecedent heating/mixing
upstream of the Ohio Valley may continue to result in less
aggressive moistening compared to most guidance. However, with
relatively cool midlevel temperatures (-14C to -16C at 500 mb), even
dewpoints in the low/mid 50s F will result in moderate buoyancy
(MLCAPE of 1000-1500 J/kg) where sufficient heating occurs.
The greatest confidence in diurnal storm development currently
resides within the eastern portion of the primary buoyancy plume
across PA and eastern OH, where weaker capping and a modest
warm-advection regime could result in isolated to widely scattered
supercell development along/ahead of the front. Weaker ascent with
southwest extent reduces confidence in development across the lower
Ohio Valley, though isolated supercell development cannot be ruled
out in this region as well. An increase in storm coverage is
expected into Sunday night as the cold front begins to surge
southeastward, though much of the nocturnal activity may tend to be
anafrontal and somewhat elevated.
Large hail (potentially to the size of golf balls or larger) could
accompany any longer-lived supercells during the afternoon and
evening. The environment will also be favorable for damaging-wind
potential, especially where stronger diurnal heating occurs, though
potential for organized clustering is uncertain due to the eventual
undercutting frontal passage. Also, while flow will remain rather
veered, low-level shear/SRH may be sufficient to support some
supercell tornado threat, conditional upon sufficient low-level
moistening. A corridor of greater tornado probabilities may
eventually be needed, if trends support more substantial moisture
return than currently expected.
..Dean.. 03/21/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0152 PM CDT Sat Mar 21 2026
Valid 231200Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
GA/SC AND SOUTHERN NC...
...SUMMARY...
Isolated strong to severe storms are possible on Monday across parts
of the Carolinas and Georgia.
...Parts of the Carolinas and Georgia...
A mid/upper-level shortwave trough initially near the lower Great
Lakes region is forecast to move offshore of New England by Monday
night. In the wake of this shortwave, a cold front will continue
moving southward across parts of the Carolinas and Southeast. Along
and south of the front, heating and modest low-level moisture (with
dewpoints in the 50s to near 60 F) will result in some diurnal
destabilization, with MLCAPE potentially increasing into the
500-1000 J/kg range.
With generally limited frontal convergence and only weak to modest
large-scale ascent, storm coverage may remain isolated near/south of
the front. Modest west-northwesterly mid/upper-level flow will
provide sufficient deep-layer shear for some storm organization, if
any robust updrafts can be sustained. Isolated hail and/or
strong/damaging gusts could occur with the strongest storms, though
coverage appears limited at this time.
..Dean.. 03/21/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1040 AM CDT Sat Mar 21 2026
Valid 211700Z - 221200Z
...CRITICAL FIRE WEATHER AREA FOR PARTS OF CENTRAL/EASTERN
WYOMING...NORTHWEST COLORADO...SOUTHWEST SOUTH DAKOTA...WESTERN
NEBRASKA PANHANDLE...
The eastern edge of the Elevated area over southwest Iowa was
expanded eastward to account for the latest forecast guidance
advecting dry air farther east ahead of the cold frontal passage
tonight. RHs over southern Iowa and northern Missouri are expected
to drop below 25% during peak heating this afternoon coinciding with
sustained southwest winds of 10-20 mph. Farther west, mid-morning
surface observations are already indicating strong southwest winds
of 15-25 mph combined with RHs under 25% over the higher elevations
within the Critical area over Wyoming and surrounding areas. The
latest forecast guidance shows that southern portions of the
Elevated area across the southern half of New Mexico and Texas will
struggle to see widespread strong winds. Still, at least locally
elevated conditions are expected over these areas today where fuels
are very receptive to ignition and spread given summertime-like
temperatures and very dry air over the last several days.
..Stearns.. 03/21/2026
.PREV DISCUSSION... /ISSUED 1234 AM CDT Sat Mar 21 2026/
...Synopsis...
Upper-level ridging will continue across much of the U.S. today.
However, some modest decrease in the amplitude of this feature can
be expected. The strongest upper-level winds will remain across the
northern tier states with some extension into the central Rockies. A
stout surface trough/cold front will begin to move south through the
northern/central Plains.
...Wyoming into far western Nebraska/South Dakota...
The combination of the strongest mid-level winds and the surface low
to the east will promote Critical fire weather conditions during the
afternoon. Winds of 20-25 mph (perhaps locally higher) and RH of
10-15% can be expected. The cold front will move through during the
late evening into the overnight. Gusty north winds are expected in
its wake.
...Colorado Foothills/Front Range...
Conditions within the typical wind prone areas will not likely be
significantly different than farther north given the cross terrain
pressure gradient. Winds of 15-25 mph and RH of 5-15% are probable.
While these meteorological conditions would mean Critical fire
weather, recent precipitation has impacted fuels and updated ERC
data suggest that Critical fire weather may only occur locally. The
cold front will not likely impact this region until around Sunday
morning.
...Southwest into central/southern Plains...
A very broad area of elevated fire weather is forecast to develop
this afternoon. The warm to hot temperatures and lack of rainfall
continue to cure fuels in these areas. Very dry conditions are
likely in the Southwest (RH of 5-15%) with modest improvements to
around 15-25% in the central Plains near the Missouri River. Winds
of 15-20 mph will be most common, but locally higher speeds are
possible especially in the terrain of the Southwest.
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1241 PM CDT Sat Mar 21 2026
Valid 221200Z - 231200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE
TEXAS...PANHANDLE/SOUTH PLAINS...ROLLING PLAINS...SOUTHWEST
OKLAHOMA...
The Critical area was expanded slightly northward to account for
pre-frontal wind/RH meeting necessary thresholds before the arrival
of the impending cold front in the late morning hours. The frontal
boundary is expected to move through the Critical area and arrive
across southwest Texas by around sunset. Thereafter, the front will
continue to surge southwest across eastern New Mexico and into far
west Texas as RHs across the region also diurnally increase. The
Elevated area was also expanded to the south and west along the
International border to include the Trans Pecos region and portions
of southeast Arizona to account for the frontal boundary interaction
as well as strong westerly winds within the well-mixed boundary
layer during peak heating.
Consideration was given to retracting the northern extent of the
Elevated area south across Kansas due to the anticipated timing of
the cold front. However, given that the temperature gradient is
somewhat weak, as was previously mentioned, RHs behind the front are
expected to remain low. This dry air will combine with northerly
winds to promote a period of elevated conditions in the post-frontal
regime. While uncertainty remains as to cloud cover and how far
north these conditions may extend, trends will be monitored with
future forecast issuances.
..Stearns.. 03/21/2026
.PREV DISCUSSION... /ISSUED 1236 AM CDT Sat Mar 21 2026/
...Synopsis...
Strong upper-level flow will be maintained across the northern U.S.
on Sunday. The upper ridge will remain largely flattened until some
amplification occurs toward Monday morning. The amplification of the
upper-level pattern will help push a cold front through the southern
Plains during the morning. The front may eventually slow/stall
near/south of the Red River latitude.
...Texas and Oklahoma...
A somewhat complex fire weather setup will develop during the
morning and persist into the afternoon as the cold front makes
southward progress. The overall temperature gradient will be rather
modest and RH recovery behind the boundary will not be overly quick
to occur. Some upper-level clouds can be expected to dampen surface
heating, especially with northern extent. Even so, temperatures
could still reach the 70s into the 80s. Winds behind the front will
range from 20-25 mph along with stronger gusts. RH will be the main
uncertainty in this scenario, but state of fuels and the strong
winds would still keep fire weather concerns high even with 15-25%
RH. Near and south of the front, however, it is more probable to see
10-20% RH. Stronger, gusty winds are also expected just ahead of the
front within the Edwards Plateau and Rolling Plains. There, Critical
conditions are expected as well.
...Kansas...
Winds of around 25 mph are expected to persist the longest across
much of Kansas. RH will likely be 25-35% on account of upper-level
clouds and slightly cooler temperatures. That said, dry grasses will
support ignition/spread due to the strong, gusty winds.
...Southwest...
Very dry conditions will continue as RH falls into the single digits
in many locations during the afternoon. Winds will generally be
weaker here, but 10-15 mph (locally higher in the terrain) will
support an Elevated fire weather threat given dry fuels.
...Please see www.spc.noaa.gov/fire for graphic product...
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