RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1134 AM CDT Sat May 23 2026
Valid 231630Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MISSISSIPPI VALLEY AND SOUTHERN HIGH PLAINS/WEST TEXAS...
...SUMMARY...
Severe thunderstorms are possible today mainly across the Lower
Mississippi Valley and parts of West Texas. Other more isolated
severe storms are possible in portions of the Southeast, Ohio, and
the central High Plains.
...Lower Mississippi Valley...
An ongoing semi-well-organized cluster of storms appears to be aided
by an MCV, and will likely continue east-northeastward today across
the ArkLaMiss and broader parts of Mississippi, to the north of more
extensive weaker convection closer to the coast in southern
Louisiana. Ample heating ahead of the cluster and steepening
low-level lapse rates will support wind potential aside from a
modest MCV-related flow enhancement. A brief tornado could also
occur, although thunderstorm wind damage is most probable.
...West Texas/Southern High Plains...
Relatively weak mid-level flow and an ill-defined surface pattern
aptly characterize the severe-potential setup for later today into
the evening across this region. Residual low-level moisture and
steep 700-500 mb lapse rates (reference the 12 UTC Midland, TX raob;
8.7 deg C/km) in combination with strong heating will result in
moderate instability developing by mid-late afternoon, stronger with
southward extent across the Texas South Plains into southwest Texas.
At least widely scattered thunderstorms are forecast to develop from
near the Colorado/Panhandles border region southward into the
Edwards Plateau. Isolated large hail and severe wind gusts will be
the primary severe hazards. A gradual clustering is expected during
the evening before this activity diminishes by late evening.
...Georgia/South Carolina...
A weak mid-level disturbance will move east-northeastward today.
Ahead of it, adequate heating of a moist boundary layer will yield
500-1000 J/kg MLCAPE by early afternoon and scattered
showers/thunderstorms are forecast. Deep-layer shear will support
some multicellular organization in the form of a few thunderstorm
clusters. The stronger water-loaded downdrafts will potentially
yield a localized wind-damage risk during the afternoon before this
threat wanes by early evening.
...Central High Plains...
Isolated thunderstorms are expected to develop late this afternoon
within a belt of stronger cyclonic mid-level flow associated with a
north-central U.S. larger-scale mid-level trough. The 30-40 kt
500-mb flow and steepened surface to 400-mb lapse rates may support
a couple of locally stronger thunderstorms late this afternoon
through early evening. Locally severe hail/wind will be the threats
with these storms.
...Ohio...
A couple of rotating storms could develop regionally this afternoon
within a belt of residually strong low-level flow. A brief/low-end
tornado threat may exist.
..Guyer/Lyons.. 05/23/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0228 PM CDT Sat May 23 2026
Valid 232000Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE LOWER MISSISSIPPI VALLEY AND THE SOUTHERN HIGH PLAINS...
...SUMMARY...
Severe thunderstorms are possible through evening, mainly across the
Lower Mississippi Valley and parts of West Texas. Other more
isolated severe storms are possible in portions of the Southeast,
Ohio, and the central High Plains.
...20z Update...
The only changes to the 20z Day 1 Outlook are to remove
probabilities across parts of TX/LA/MS in the wake of an
northeastward-advancing MCS. Otherwise, forecast reasoning remains
similar to the previous outlook, detailed below. For more detailed
information on short term severe potential along the TX Coast and
the central High Plains, reference MCDs 838 and 839.
..Leitman.. 05/23/2026
.PREV DISCUSSION... /ISSUED 1134 AM CDT Sat May 23 2026/
...Lower Mississippi Valley...
An ongoing semi-well-organized cluster of storms appears to be aided
by an MCV, and will likely continue east-northeastward today across
the ArkLaMiss and broader parts of Mississippi, to the north of more
extensive weaker convection closer to the coast in southern
Louisiana. Ample heating ahead of the cluster and steepening
low-level lapse rates will support wind potential aside from a
modest MCV-related flow enhancement. A brief tornado could also
occur, although thunderstorm wind damage is most probable.
...West Texas/Southern High Plains...
Relatively weak mid-level flow and an ill-defined surface pattern
aptly characterize the severe-potential setup for later today into
the evening across this region. Residual low-level moisture and
steep 700-500 mb lapse rates (reference the 12 UTC Midland, TX raob;
8.7 deg C/km) in combination with strong heating will result in
moderate instability developing by mid-late afternoon, stronger with
southward extent across the Texas South Plains into southwest Texas.
At least widely scattered thunderstorms are forecast to develop from
near the Colorado/Panhandles border region southward into the
Edwards Plateau. Isolated large hail and severe wind gusts will be
the primary severe hazards. A gradual clustering is expected during
the evening before this activity diminishes by late evening.
...Georgia/South Carolina...
A weak mid-level disturbance will move east-northeastward today.
Ahead of it, adequate heating of a moist boundary layer will yield
500-1000 J/kg MLCAPE by early afternoon and scattered
showers/thunderstorms are forecast. Deep-layer shear will support
some multicellular organization in the form of a few thunderstorm
clusters. The stronger water-loaded downdrafts will potentially
yield a localized wind-damage risk during the afternoon before this
threat wanes by early evening.
...Central High Plains...
Isolated thunderstorms are expected to develop late this afternoon
within a belt of stronger cyclonic mid-level flow associated with a
north-central U.S. larger-scale mid-level trough. The 30-40 kt
500-mb flow and steepened surface to 400-mb lapse rates may support
a couple of locally stronger thunderstorms late this afternoon
through early evening. Locally severe hail/wind will be the threats
with these storms.
...Ohio...
A couple of rotating storms could develop regionally this afternoon
within a belt of residually strong low-level flow. A brief/low-end
tornado threat may exist.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1225 PM CDT Sat May 23 2026
Valid 241200Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM WESTERN KS
INTO CENTRAL/EASTERN NE...SOUTHEAST SD...SOUTHWEST MN...NORTHWEST
IA...
...SUMMARY...
Strong to locally severe storms are possible from parts of the
central Plains into the Upper Midwest, mainly Sunday afternoon and
evening. Isolated large to very large hail and localized severe
gusts will be possible.
...Central Plains into the Upper Midwest...
A mid/upper-level shortwave trough initially over the Upper Midwest
will move over the Great Lakes region on Sunday. Broad southerly
flow between a surface ridge near the mid MS Valley and a lee trough
over the High Plains will result in some moisture return into parts
of the central Plains and Upper Midwest, though the magnitude of
this moisture return remains somewhat uncertain. Steep midlevel
lapse rates and relatively cool midlevel temperatures atop the
returning moisture will result in moderate to locally strong
destabilization by late afternoon.
Broad midlevel height rises are expected across the region, in the
wake of the departing shortwave trough. However, guidance suggests
that one or more weak midlevel vorticity maxima may aid in at least
isolated diurnal thunderstorm development near a weak surface
trough/dryline from central NE into southeast SD/southwest MN.
Deep-layer flow will remain generally modest, but veering wind
profiles and 30-40 kt of effective shear will conditionally support
supercells, if surface-based development can be sustained. Large to
very large hail and localized severe gusts could accompany any
supercell development during the afternoon and evening.
A Level 2/Slight Risk upgrade was considered for parts of the
region, but due to uncertainties regarding low-level moisture and
storm coverage, have opted to maintain a Level 1/Marginal Risk, with
a conditional area highlighting very large hail potential, should
any sustained supercells develop.
...Southeast/southern Appalachians...
Scattered thunderstorm development is again expected across the
region, within a moist and uncapped environment. A belt of 20-30 kt
midlevel flow to the east of the mid/upper trough across TX will
provide modest deep-layer shear, but weak midlevel lapse rates will
tend to limit updraft intensity. Locally damaging wind cannot be
ruled out with convection across the region, but the
organized-severe threat currently appears too limited and nebulous
to include probabilities at this time. If a robust MCV emerges from
extensive convection near the Gulf Coast, then somewhat more
organized severe potential could evolve through the day.
...LA Gulf Coast/Lower MS Valley vicinity...
Widespread convection is expected to persist from D1/Saturday into
D2/Sunday across parts of the LA Gulf Coast and lower MS Valley, as
the nearly stationary mid/upper trough over TX interacts with rich
moisture. Generally weak flow and lapse rates are currently expected
to limit the organized-severe threat. Any more organized potential
for a brief tornado or locally damaging wind would likely be
contingent on MCV development, but this scenario remains highly
uncertain at this time.
...Lower OH Valley/Allegheny Plateau...
Scattered thunderstorms will be possible across parts of the Ohio
Valley and Allegheny Plateau during the afternoon, in association
with the mid/upper trough moving across the Great Lakes region.
Modest midlevel flow will overspread the region and isolated strong
storms will be possible, but weak lapse rates and modest buoyancy
are expected to limit severe potential.
..Dean.. 05/23/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 PM CDT Sat May 23 2026
Valid 251200Z - 261200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe-thunderstorm potential currently appears low for
Monday. Isolated strong storms may develop across parts of the Great
Plains, Upper Midwest, and Southeast.
...Synopsis...
Little change to the overall pattern expected across the CONUS on
Monday. A very slow-moving mid/upper low/trough is expected to
remain in the vicinity of east TX/western LA, which will maintain
potential for scattered to widespread thunderstorms across parts of
the Gulf Coast and Southeast. Another slow-moving mid/upper trough
will support thunderstorm potential across parts of the Southwest
and southern Rockies. A vigorous mid/upper-level shortwave trough
will move into the Pacific Northwest during the afternoon and
evening.
...Central Plains into the Upper Midwest/Great Lakes region...
Moderate to locally strong buoyancy may develop Monday afternoon
from parts of the central Plains into the Upper Midwest/Great Lakes,
though some uncertainty remains regarding the quality of low-level
moisture across this region.
Modest west-northwesterly midlevel flow will result in 30-40 kt of
effective shear across parts of MN/WI and Upper MI, but confidence
in storm development within this conditionally favorable environment
is low, with midlevel height rises and generally minimal large-scale
ascent expected across the region.
Forcing will also be weak into parts of the central Plains, but
strong heating and presence of a remnant surface boundary may
support isolated storm development from late afternoon into the
evening. A threat for localized hail and strong to severe gusts
could accompany the strongest storms, but weak deep-layer shear and
uncertainty regarding storm coverage limit confidence in organized
severe potential at this time.
...Southern NM into west TX...
Isolated strong storms could develop on Monday from parts of
southern NM into west TX, in advance of the mid/upper trough over
the Southwest. At this time, it appears that the stronger forcing
associated with the upper trough will remain displaced from the
richer moisture across parts of central/southwest TX through most of
the period. However, a faster trough ejection and/or more
substantial moisture return could result in an isolated severe
threat during the late afternoon and evening.
...Parts of the Gulf Coast/Southeast...
Modest enhancement to midlevel flow may continue across parts of the
Gulf Coast and Southeast, to the east of the persistent mid/upper
low/trough over east TX. Depending on the evolution of D1/D2
convection and any MCV development, a low-probability severe threat
could evolve over some part of this region, but confidence is much
too low to include probabilities at this time.
..Dean.. 05/23/2026
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