RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Thu Aug 06 2026
Valid 061630Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS INTO THE OZARKS...THE CAROLINAS INTO THE
MID-ATLANTIC AND NORTHEAST...AND FAR NORTHEAST COLORADO INTO PARTS
OF NEBRASKA AND SOUTHERN SOUTH DAKOTA...
...SUMMARY...
Generally isolated strong to severe thunderstorms capable of
producing hail and damaging winds appear possible across parts of
the southern/central Plains into the Ozarks. Isolated strong to
locally severe gusts capable of wind damage may also occur from
parts of the Carolinas into the Mid-Atlantic and Northeast.
...Southern/Central Plains into the Ozarks...
Ongoing convection in MO and along the KS/OK border late this
morning has been aided by modest low-level warm/moist advection in
the vicinity of a slow-moving surface boundary. Current expectations
are for gradual destabilization to occur through the afternoon
along/south of this boundary from the southern High Plains eastward
to parts of the Ozarks. This region will remain on the southern
periphery of large-scale troughing centered over Canada and the
northern Plains, with nebulous/weak forcing for ascent evident along
the surface front. This leads to low confidence in renewed
thunderstorms later this afternoon into the evening. Based on this
and trends in 12Z guidance, have removed the Slight Risk for
severe/damaging winds. Still, an isolated hail/wind threat remains
apparent along the length of this boundary, as moderate instability
and sufficient deep-layer shear will be present to support updraft
organization with any cells that can form/be sustained. A greater
signal for scattered thunderstorm development exists this
evening/overnight across parts of KS/MO as a low-level jet gradually
strengthens in this time frame. Have expanded severe hail/wind
probabilities northward a bit to account for this potential.
...Carolinas into the Mid-Atlantic and Northeast...
Around 20-35 kt of southwesterly mid-level flow will exist over
parts of the Mid-Atlantic into the Northeast today. At the surface,
a weak trough will be located from the coastal VA
north-northeastward into eastern NY. As surface temperatures
continue to warm into the 80s with filtered daytime heating,
thunderstorms will develop in the foothills of the Appalachians and
subsequently move east-northeastward into the lower elevations and
toward the surface trough. While mid-level lapse rates will remain
poor, a rather moist low-level airmass will contribute to moderate
instability this afternoon (MLCAPE generally 1000-2500 J/kg).
Greater instability and steeper low-level lapse rates are forecast
with southward extent into the western Carolinas where mid-level
flow will be comparatively weaker. Some of the stronger water-loaded
downdrafts will be capable of producing occasional damaging winds.
...Colorado/Nebraska/South Dakota...
West-northwesterly mid-level flow will persist over much of the
north-central CONUS through the period. At the surface, an axis of
greater low-level moisture will exist from northeast CO/western NE
into southern SD along/east of a weak surface trough, where
dewpoints will generally be in the 60s. Near this axis, latest
NAM/RAP forecasts show a narrow corridor of moderate instability
this afternoon, with MLCAPE up to 2000-2500 J/kg. Although
large-scale ascent will remain weak/nebulous across this region, any
cell that can initiate near the instability axis would be capable of
producing isolated severe gusts/large hail. Have therefore
maintained the Marginal Risk across this region with some expansion.
But, given low confidence in convective initiation, refrained from
including greater severe wind/hail probabilities at this time.
..Gleason/Lyons.. 08/06/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Thu Aug 06 2026
Valid 062000Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS INTO THE OZARKS...THE CAROLINAS INTO THE
MID-ATLANTIC AND NORTHEAST...AND FAR NORTHEAST COLORADO INTO PARTS
OF NEBRASKA AND SOUTHERN SOUTH DAKOTA...
...SUMMARY...
Isolated strong to severe thunderstorms capable of producing hail
and damaging winds are possible across parts of the southern/central
Plains into the Ozarks. Isolated damaging wind gusts may also occur
from parts of the Carolinas into the Mid-Atlantic and Northeast.
...20Z Update...
The forecast remains on track, and only minor adjustments were made
with this update. In the near term, the primary concern will be the
potential for a few organized storms in southern MO capable of
producing severe hail and damaging wind gusts. See MCD 1843 more
details.
..Weinman.. 08/06/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Aug 06 2026/
...Southern/Central Plains into the Ozarks...
Ongoing convection in MO and along the KS/OK border late this
morning has been aided by modest low-level warm/moist advection in
the vicinity of a slow-moving surface boundary. Current expectations
are for gradual destabilization to occur through the afternoon
along/south of this boundary from the southern High Plains eastward
to parts of the Ozarks. This region will remain on the southern
periphery of large-scale troughing centered over Canada and the
northern Plains, with nebulous/weak forcing for ascent evident along
the surface front. This leads to low confidence in renewed
thunderstorms later this afternoon into the evening. Based on this
and trends in 12Z guidance, have removed the Slight Risk for
severe/damaging winds. Still, an isolated hail/wind threat remains
apparent along the length of this boundary, as moderate instability
and sufficient deep-layer shear will be present to support updraft
organization with any cells that can form/be sustained. A greater
signal for scattered thunderstorm development exists this
evening/overnight across parts of KS/MO as a low-level jet gradually
strengthens in this time frame. Have expanded severe hail/wind
probabilities northward a bit to account for this potential.
...Carolinas into the Mid-Atlantic and Northeast...
Around 20-35 kt of southwesterly mid-level flow will exist over
parts of the Mid-Atlantic into the Northeast today. At the surface,
a weak trough will be located from the coastal VA
north-northeastward into eastern NY. As surface temperatures
continue to warm into the 80s with filtered daytime heating,
thunderstorms will develop in the foothills of the Appalachians and
subsequently move east-northeastward into the lower elevations and
toward the surface trough. While mid-level lapse rates will remain
poor, a rather moist low-level airmass will contribute to moderate
instability this afternoon (MLCAPE generally 1000-2500 J/kg).
Greater instability and steeper low-level lapse rates are forecast
with southward extent into the western Carolinas where mid-level
flow will be comparatively weaker. Some of the stronger water-loaded
downdrafts will be capable of producing occasional damaging winds.
...Colorado/Nebraska/South Dakota...
West-northwesterly mid-level flow will persist over much of the
north-central CONUS through the period. At the surface, an axis of
greater low-level moisture will exist from northeast CO/western NE
into southern SD along/east of a weak surface trough, where
dewpoints will generally be in the 60s. Near this axis, latest
NAM/RAP forecasts show a narrow corridor of moderate instability
this afternoon, with MLCAPE up to 2000-2500 J/kg. Although
large-scale ascent will remain weak/nebulous across this region, any
cell that can initiate near the instability axis would be capable of
producing isolated severe gusts/large hail. Have therefore
maintained the Marginal Risk across this region with some expansion.
But, given low confidence in convective initiation, refrained from
including greater severe wind/hail probabilities at this time.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 PM CDT Thu Aug 06 2026
Valid 071200Z - 081200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
MID-MISSOURI VALLEY INTO WISCONSIN AND THE UPPER PENINSULA OF
MICHIGAN...PARTS OF THE NORTHERN MID-ATLANTIC...SOUTH-CENTRAL SOUTH
DAKOTA INTO NORTH-CENTRAL NEBRASKA...
...SUMMARY...
A few strong to severe storms may occur from the Mid-Missouri Valley
across Wisconsin and into Upper Michigan Friday, with areas of
strong/damaging wind gusts and isolated marginal hail. Other storms
may produce locally damaging gusts over parts of the Northeast and
hail over parts of central Nebraska/South Dakota.
...Mid-Missouri Valley into Wisconsin/Upper Peninsular Michigan...
A cold front will move into the Upper Midwest during the afternoon.
Moisture return ahead of the front will maintain upper 60s F farther
north to low 70s F dewpoints across Iowa/southern Minnesota.
2000-3000 J/kg MLCAPE is expected during the afternoon. The
approaching mid-level jet will bring stronger mid-level flow and
30-45 kt of effective shear to the region (stronger shear will
generally exist with southwestward extent). Initial activity will
likely be cellular with a tendency to become more linear with time.
Large hail and damaging winds will be the main concerns. Given the
stronger buoyancy and shear within Iowa, there is greater potential
for an MCS to develop with an associated greater risk for wind
damage. Variance is relatively high within model guidance as to
where this corridor will exist due in part to the subtle forcing.
Some guidance suggests a cluster of activity is possible during the
morning hours. This could intensify as the airmass destabilizes
during the day. Other guidance suggests limited morning activity
with storms forming along the front farther east. An increase in
wind probabilities is possible as confidence increases.
...South Dakota/Nebraska...
At least moderate elevated instability is forecast to develop as a
low-level jet intensifies within the region late Friday night into
early Saturday morning. Several CAMs and global guidance suggest
development will occur. Sufficient mid-level flow on the southern
flank of the northern Plains trough will allow for organized storms.
Steep mid-level lapse rates will support a risk for isolated large
hail.
...Northern Mid-Atlantic...
Though mid-level winds will be slightly weaker than on Thursday, the
approach of a modest trough will allow for marginally organized
storms within a very moist environment. Afternoon MLCAPE will near
2000 J/kg in parts of the Mid-Atlantic. Model consensus continues to
support the potential for widely scattered to scattered storms
within this weakly capped airmass. Isolated damaging winds will be
possible.
...Southern Plains into the Ozarks...
Given the presence of a stalled boundary/outflow, some potential
exists for storms to develop during the afternoon. Confidence on
where this boundary will be placed is quite low at this time.
Deep-layer shear will also be somewhat weak as well. Given these
factors, severe wind probabilities will be withheld, though isolated
wind damage could occur.
..Wendt.. 08/06/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Thu Aug 06 2026
Valid 081200Z - 091200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
CENTRAL SOUTH DAKOTA/NEBRASKA INTO IOWA AND NORTHERN MISSOURI...
...SUMMARY...
A corridor of damaging winds may develop Saturday afternoon and
evening from South Dakota/Nebraska into Iowa/Northern Missouri.
...South Dakota/Nebraska into Mid-Missouri/Mississippi Valleys...
Models are in general agreement that convection will be ongoing
early Saturday morning near the central South Dakota/Nebraska
border. There is some potential for this activity to intensify as
destabilization occurs in eastern Nebraska into Iowa during the
afternoon. Moderate mid-level flow will extend into these regions.
Strong heating to the south of a developing warm front/outflow
boundary will lead to a strongly unstable environment. The two main
questions for this forecast will be whether the early morning
activity can develop enough of a cold pool to persist through the
diurnally unfavorable morning time frame, and what the impacts from
potential convection in Iowa on Friday will be. The overall setup
and environment appear favorable for MCS development. Higher
probabilities will likely be needed as confidence in the corridor of
greater risk increases.
...Mid-Atlantic...
Some potential for thunderstorms exists during the afternoon as a
very moist and uncapped airmass will remain in place on Saturday.
Mid-level flow will be stronger with northern extent with cyclonic
flow aloft continuing over the Great Lakes/New England. Though
widely scattered to scattered storms are probable, effective shear
and mid-level lapse rates will be weak. Furthermore, mesoscale
features aiding convective organization are not evident in model
guidance. There may be an embedded perturbation within the flow
aloft, but models differ on the location/intensity of these
features. Uncertainty in storm severity remains high.
..Wendt.. 08/06/2026
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