RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Wed Jul 01 2026
Valid 011200Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST INTO THE UPPER GREAT LAKES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS AND THE NORTHEAST...
...SUMMARY...
Scattered severe thunderstorms are forecast across the Upper
Midwest/Great Lakes today and tonight. Damaging wind gusts (some to
80 mph) are the main concern, in addition to isolated large to very
large hail and a few tornadoes. Additional severe storms are
possible across parts of the the central High Plains and Northeast.
...Midwest and Upper Great Lakes ...
Within a belt of strong midlevel southwesterly flow extending from
the central/northern Plains into the Upper Midwest/Great Lakes, a
convectively augmented midlevel impulse should be the focus for
ongoing/morning strong-severe storms over parts of southern MN and
vicinity. This activity will mainly pose a risk for damaging gusts
and possibly large hail. These storms should continue
developing/spreading east-northeastward into the Upper Midwest along
a stationary boundary, where diurnal heating of a moist air mass and
steep lapse rates will lead to strong surface-based buoyancy. This,
combined with around 40 kt of effective shear, will favor a mix of
supercells and organized clusters. Scattered damaging wind gusts,
large to very large hail, and a few tornadoes will all be possible.
Thereafter, high-resolution guidance is in general agreement,
depicting a second round of upstream thunderstorm development during
the afternoon/evening in the vicinity of southern MN -- likely in
response to a strengthening low-level jet and related isentropic
lift. Similarly, these storms should spread east-northeastward
through a strongly unstable air mass and 40-50 kt of effective shear
(with increasing clockwise-curved hodographs). Swaths of damaging
winds (some gusts near 80 mph possible), large to very large hail,
and a few tornadoes will be possible.
...Central High Plains...
High-based thunderstorm development is expected along a
north/south-oriented lee trough/dryline during the afternoon and
evening. Despite modest deep-layer shear (around 25-30 kt), steep
low/mid-level lapse rates will contribute to a strongly unstable air
mass. A mix of loosely organized clusters and possibly some
supercell structures will be capable of producing severe wind gusts
and large hail.
...Northeast...
Enhanced west-northwesterly midlevel flow will persist across the
Northeast, where a warm/moist air mass will contribute to around
3000 J/kg MLCAPE. While nebulous mesoscale forcing for ascent casts
uncertainty on overall convective coverage and evolution, the strong
buoyancy and a veering wind profile (albeit modest deep-layer shear)
will favor east-southeastward-spreading convection capable of
damaging wind gusts and isolated hail during the afternoon and again
during the evening/nighttime hours.
...Southeast...
Along the southern periphery of a midlevel anticyclone centered over
the central Appalachians, a belt of 20-30-kt east-southeasterly flow
in the 700-500-mb layer will overspread a hot/moist air mass with
4500 J/kg MLCAPE during the afternoon. Despite limited deep-layer
shear, the extreme buoyancy and well-mixed boundary layer will be
favorable for wet microbursts with the stronger convective clusters
that evolve.
...Northern Rockies/High Plains...
Isolated to widely scattered thunderstorms are expected ahead of a
slow-moving midlevel trough moving across the Northwest. Preceding
the trough, around 40 kt of midlevel southwesterly flow and a weakly
unstable air mass will support a couple loosely organized clusters
capable of producing severe wind gusts during the afternoon and
evening.
..Weinman/Chalmers.. 07/01/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Wed Jul 01 2026
Valid 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Strong to severe storms will be possible from the northern Plains
into the Midwest and Great Lakes regions on Thursday. Isolated
strong to severe storms may also occur in the Tennessee
Valley/Southeast as well as parts of the Northeast.
...Northern Plains into Mid-Missouri Valley...
Broad cyclonic flow aloft across the Rockies will promote a lee
trough and a modest surface low in the vicinity of the Black Hills.
A surface boundary will arc from eastern Montana into northern South
Dakota and southern Minnesota. Moisture advection into the High
Plains will couple with higher terrain of MT/WY/SD as well as the
surface boundary to initiate convection during the afternoon.
Supercells will be likely initially with an attendant risk of large
to very-large hail, severe winds, and a tornado or two. Mid-level
lapse rates of 8-9 C/km will promote rapid intensification and
strong downdrafts. Couple this with modest effective shear of 40-45
kt and upscale growth will be likely with time. An MCS is possible
and would likely track along the surface boundary. Wind gusts of 75+
mph would be possible with this activity.
While most guidance does not show development along the surface
boundary towards the mid-Missouri Valley, there will be weak warm
advection ongoing through the day that will increase by late
afternoon. Should storms develop here, they would likely be more
isolated/cellular. A similar threat for large/very-large hail and
severe gusts would exist along with a locally greater tornado
threat. This would especially be the case if storms can remain
discrete into the evening when low-level shear increases. Depending
on whether this activity develops/evolves, this will have an impact
on the spatial extent of a greater threat for severe winds into the
evening and beyond. Given that uncertainty, the Slight Risk will be
maintained with potential increases in wind probabilities in
subsequent outlooks as confidence increases.
...Midwest...
Convection is expected to be ongoing in parts of the region. At
least an isolated threat for damaging winds and large hail would
exist with this activity. There remain some potential for
intensification to occur as storms move east during the day. The
Slight Risk remains in place into far western Lower Michigan to
account for this potential. Later in the afternoon, redevelopment is
possible along the outflow from earlier activity. The most robust
model signals are in Iowa and parts of Wisconsin. Large hail would
be possible especially in Iowa where mid-level lapse rates would be
steeper. Otherwise damaging winds would be the main threat. A
tornado or two could occur, but low-level shear will be rather weak.
...Northeast...
Strong buoyancy and modest shear will again be in place across the
region. At least isolated storms are possible during the afternoon.
Damaging winds should be the main threat with this activity.
Isolated large hail may occur with the strongest storms, but modest
mid-level lapse rates will limit this threat. Some guidance does
show more organized activity moving into the region from
Ontario/Quebec, but this may not occur until late afternoon.
Confidence in that scenario occurring is too low for an increase in
wind probabilities.
...Tennessee Valley/Southeast...
Strong heating of a very moist airmass will promote scattered to
numerous storms during the afternoon. Congealing outflows will help
to organize activity even with very weak shear. Given mid-level
lapse rates of 7-7.5 C/km, at least marginally severe storms will be
possible. Damaging winds are the expected hazard.
..Wendt.. 07/01/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0233 AM CDT Wed Jul 01 2026
Valid 031200Z - 041200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN SOUTHERN
SOUTH DAKOTA INTO NORTHERN NEBRASKA...
...SUMMARY...
Isolated to scattered severe storms are possible from the
northern/central Plains into the Midwest and Mid-Atlantic on Friday.
...Synopsis...
A complex forecast is evident on Friday. The upper-level trough in
the West will lose some amplitude, though modest flow will remain
across portions of the central/northern High Plains along with
embedded shortwave troughs. The most complicating piece of the
forecast will be the convection that is expected to be ongoing
within the Midwest during the morning. The NAM/GFS is decidedly
farther north than the ECMWF with this activity. The NAM has a
strong enough MCS/MCV that it pushes the moist, unstable airmass
farther south through the day whereas the ECMWF keeps a favorable
airmass into the northern Plains. Given the large spatial extent of
strong to severe storm potential, a broad marginal is in place from
the northern Plains into the Midwest/Mid-Atlantic. Shear and
mid-level lapse rates will be more favorable within the High Plains.
A more targeted Slight Risk was added for southern South Dakota into
Nebraska. Here, there will be potential for severe storms along the
outflow from the expected MCS on Thursday. This area has been biased
southward given the potential for storms being elevated atop outflow
farther north. Some northward adjustment is possible if greater
airmass recovery occurs. Another area where greater probabilities
may be needed is in the Great Lakes region depending on the
track/intensity of the MCV that moves eastward out of the Missouri
Valley vicinity. Into the Ohio Valley and Mid-Atlantic, storm
coverage will be more isolated and deep-layer shear much weaker.
That said, a very unstable airmass could promote isolated damaging
downburst winds.
..Wendt.. 07/01/2026
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