RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Wed Jul 08 2026
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
CENTRAL PLAINS INTO THE MID MISSOURI AND UPPER MISSISSIPPI
VALLEYS...
...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon and evening across parts of the central Plains, and from
the Missouri Valley into the upper Mississippi Valley. Isolated
severe gusts may also occur in parts of the northern High Plains and
from North Carolina into southern Virginia.
...Central Plains/Mid Missouri Valley/Upper Mississippi Valley...
At mid-levels, heights will fall today across much of the
north-central U.S. as a subtle shortwave trough moves
east-southeastward across the region. At the surface, a cold front
will advance southeastward into the central Plains and mid Missouri
Valley by afternoon. Along and ahead of the front, surface dewpoints
will range from the mid 60s to the lower 70s F. As surface
temperatures warm, moderate instability will develop along this
west-southwest to east-northeast corridor. Low-level convergence
will be maximized along and near the front, which will be the
primary focus for convective initiation. Scattered thunderstorms
will form in the afternoon and move east-southeastward across the
instability corridor, with convective development continuing through
much of the evening. The instability, combined with moderate
deep-layer shear and steep low-level lapse rates, will support a
threat for severe wind gusts. The potential for severe wind will be
greatest with any line segment that can become sustained and
organized. Although there is some uncertainty concerning where the
greatest threat will be, it seems possible that a damaging wind
swath could occur in parts of southern Nebraska this evening, where
a 30 percent wind probability has been added.
Further northeast into central Iowa and south-central Wisconsin,
convective coverage is expected to be a bit more widely spaced.
However, deep-layer shear will be sufficient for a severe threat as
low-level lapse rates and instability become maximized late this
afternoon. The primary threat will be for severe wind gusts, with
the threat being associated with short intense line segments.
...Northern High Plains...
At the surface, a lee trough will develop today from eastern Wyoming
into eastern Montana. Along and near the trough, surface dewpoints
in the 50s F will contribute to the development of moderate
instability by afternoon. Although large-scale ascent will be
relatively weak, low-level convergence near the trough will aid
convective initiation. Thunderstorms will also develop in the higher
terrain and move eastward into the lower elevations. The
instability, combined with moderate deep-layer shear and steep low
to mid-level lapse rates will likely support a potential for
isolated severe gusts.
...North Carolina/Southern Virginia.
At the surface, a very moist airmass will be in place today from the
Mid-Atlantic southward into the Carolinas. Surface dewpoints in the
mid to upper 70s F will contribute to an axis of moderate to strong
instability across parts of North Carolina and southern Virginia.
Isolated to scattered thunderstorms will develop in the foothills of
the Appalachians, with the storms moving eastward into the lower
elevations during the afternoon. The instability combined with steep
low-level lapse rates will support an isolated wind-damage threat.
..Broyles/Moore.. 07/08/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 AM CDT Wed Jul 08 2026
Valid 091200Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY INTO
THURSDAY NIGHT ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND ACROSS
PARTS OF THE LOWER MISSOURI VALLEY INTO LOWER OHIO VALLEY...
...SUMMARY...
Scattered strong thunderstorm development, potentially including a
few evolving clusters, may impact portions of the central Great
Plains and lower Missouri Valley through lower Ohio Valley Thursday
through Thursday night, posing a risk for severe wind gusts and some
hail.
...Discussion...
Modest mid-latitude westerlies likely will remain centered near the
Canadian/U.S border through this period. In the wake of one short
wave trough slowly continuing to pivot northward into the Northwest
Territories, and ahead of another digging near the British Columbia
coast, broad mid-level ridging is forecast to build across the
central Canadian/U.S. border vicinity Thursday through Thursday
night. Downstream, to the south of a perturbation digging southeast
of Hudson/James Bays, broad mid-level troughing is forecast to
overspread the lower Great Lakes through northern Atlantic Seaboard.
In lower latitudes, a number of more subtle perturbations are
forecast to progress through generally weak zonal flow, around the
northern periphery of mid-level ridging centered in the subtropics.
However, there remains a notable signal within model output that at
least a couple of these may be amplified by developing convection,
accompanied by belts of strengthening flow which could promote
organizing convection capable of producing swaths of strong to
severe wind gusts.
While the most substantive thunderstorm development through this
period appears likely to focus east of the Front Range into portions
of the lower Missouri Valley through Ohio Valley, as well as across
parts of the northern Mid Atlantic, more widely scattered strong to
severe thunderstorm development appears possible closer to the
mid-latitude westerlies. This may focus along a weak surface front
advancing slowly southward across parts of the lower Great Lakes
through northern New England, and within lee surface troughing
across parts of the northern Great Plains.
...Lower Missouri/Ohio Valleys...
Most guidance continues to indicate the generation of one or two
notable mesoscale convective vortices and associated jet streaks, at
least initially emanating from convection developing across the
central Great Plains Wednesday night. The NAM continues to forecast
the strongest convective perturbation, though the 08/00Z run now
suggests that this will occur with convection overspreading east
central Missouri into southern Illinois late Thursday night.
Otherwise, a consensus of guidance generally suggests the
development of strengthening westerly mid-level flow (on the order
of 30-50 kt around 700 mb) in a belt across the lower Missouri
Valley during the day, before slowly shifting toward the lower Ohio
Valley through Thursday night.
Based on latest model output, strongest renewed thunderstorm
development seems most probable within forcing for ascent associated
with strengthening low-level warm advection, along an outflow
boundary trailing the initial MCV. Aided by inflow of seasonably
high boundary-layer moisture content (including surface dew points
in the 70s) supportive of CAPE on the order of 2000+ J/kg, vertical
shear may become supportive of a sustained organized convective
system with potential to produce strong to severe wind gusts by
Thursday evening into Thursday night, if not earlier.
...Front Range into central Great Plains...
Latest model output continues to indicate that moistening
southeasterly low-level flow across the high plains will destabilize
sufficiently by late afternoon to support intensifying thunderstorm
development off the Front Range. Aided by shear due to pronounced
veering of winds with height from the surface to mid-levels, this
may include widely scattered supercells initially.
Aided by forcing for ascent downstream of an approaching mid-level
perturbation, convection-allowing guidance suggests that storms will
subsequently increase in number across the high plains, with
consolidating cold pools supporting further upscale growth and
eastward propagation. Forcing for ascent near the nose of a
strengthening nocturnal southerly low-level jet may contribute to
maintenance of a cluster with potential to produce strong to severe
gusts into late evening/overnight across the southwestern Kansas
vicinity.
...Mid Atlantic...
Destabilization within lee surface troughing may become sufficient
to support thunderstorm development with potential to produce strong
wind gusts and grow upscale Thursday afternoon into evening, aided
by forcing for ascent and modest strengthening of mid-level flow,
associated with a remnant short wave impulse emerging from the
Tennessee Valley.
...Southeastern Arizona...
Convection-allowing and related guidance suggests that thunderstorm
development is probable Thursday afternoon across parts of the
Mogollon Rim into higher terrain of southwestern New Mexico, and
perhaps southeastern Arizona, around the eastern periphery of a
weakening mid-level ridge. Aided by light northeasterly steering
flow off the mountains, into a hot and deeply mixed boundary layer
with at least weak CAPE, a few strong downbursts appear possible,
with potential for upscale growth on consolidating cold pools to
generate a broader strong to severe wind gust threat into Thursday
evening.
..Kerr.. 07/08/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0212 AM CDT Wed Jul 08 2026
Valid 101200Z - 111200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A CORRIDOR
EAST OF THE SOUTHERN ROCKIES THROUGH THE CENTRAL GREAT
PLAINS...OZARK PLATEAU...AND TENNESSEE VALLEY...
...SUMMARY...
Clusters of thunderstorms accompanied by a risk for damaging wind
gusts may evolve in a corridor across parts of the central Great
Plains into Tennessee Valley Friday afternoon and evening.
...Discussion...
To the southeast of a significant digging trough offshore of the
British Columbia and Pacific Northwest coast, models continue to
indicate that an increasingly prominent mid/upper-level high may
begin to form across portions of the Colorado Valley/Plateau through
southern Rockies vicinity. Ridging is also forecast to continue
building along an axis northward through the northern U.S. Great
Plains and eastern Canadian Prairies Friday through Friday night,
while positively tilted larger-scale downstream troughing gradually
shifts into and across the northern Atlantic Seaboard.
The evolution of weak remnant troughing across the lower Missouri
Valley and central Great Plains remains much more unclear. However,
guidance generally suggests that a belt of convectively augmented
mid-level flow will linger across southern portions of the central
Great Plains through Tennessee Valley, and perhaps through southern
Mid Atlantic coastal areas.
The potential for at least moderate destabilization appears most
certain along the southern periphery of this regime, aided by a
corridor of steeper lower through mid-tropospheric lapse rates
associated with elevated mixed-layer air (probably based closer to
850 mb than 700 mb), above a seasonably moist boundary-layer.
Focused in zones of strengthening differential heating across a
remnant outflow boundary, or boundaries, the environment might
become conducive to the evolution of at least small organizing
clusters with potential to produce strong to severe surface gusts
Friday afternoon and evening.
..Kerr.. 07/08/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Wed Jul 08 2026
Valid 111200Z - 161200Z
...DISCUSSION...
There remains a general consensus in medium-range guidance that a
prominent mid-level high will build further while developing across
and northeast of the Colorado Plateau through the middle Missouri
Valley this coming weekend into early next week, within elongating
larger scale ridging. A bit more uncertainty lingers concerning the
evolution of larger-scale troughing and embedded short wavelength
developments to the northeast and east of this feature into the
early to middle portion of next week, but it still appears that this
ridging may eventually become suppressed across the Great Lakes
region.
As a plume of very warm elevated mixed-layer air advects along the
southern fringe of strengthening flow around the northern through
northeastern periphery of the mid/upper ridge, it may contribute to
an environment conducive to the initiation and evolution of
organizing thunderstorm clusters with potential to produce swaths of
damaging surface gusts. Based on latest guidance, this may tend to
initially remain north of the international border from the Great
Plains through the upper Great Lakes. However, due to spread within
and among the various model output, it remains unclear whether this
activity will pose a greater potential impact to portions of New
England or the lower Great Lakes into northern Mid Atlantic by next
Tuesday or Wednesday.
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