RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Jun 10 2026
Valid 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MISSISSIPPI VALLEY AND MIDWEST...
...SUMMARY...
Scattered to numerous severe thunderstorms with potential for large
hail in excess of two inches in diameter, a few strong tornadoes and
damaging winds with gusts over 75 mph are expected this afternoon
and evening across parts of the Upper Mississippi Valley and
Midwest.
...Upper Mississippi Valley/Midwest...
At mid-levels, a trough will move eastward into the central and
northern Plains today, as the exit region of a jet streak
overspreads the upper Mississippi Valley and Midwest. At the
surface, a cold front will advance eastward across the northern
Plains with a warm front moving into the western Great Lakes.
Between these two fronts, a very moist airmass will be in place with
surface dewpoints in the lower to mid 70s F. Early in the day, a
line of strong thunderstorms is expected to develop in western Iowa
near the western edge of the moist airmass. A potential for severe
wind gusts will be possible with this line. Eastward across the
moist sector, moderate to strong instability is expected to develop
by midday as surface temperatures warm. This will help the line to
grow upscale, potentially into a linear MCS, as it moves across
southern Wisconsin and northern Illinois early this afternoon.
Severe wind gusts and QLCS tornadoes will be possible along the
stronger parts of this line segment.
In the wake of the initial line segment, instability is expected to
increase as moisture advection and surface heating take place. An
instability axis is forecast to develop in the afternoon from
eastern Missouri northward into eastern Iowa, where MLCAPE should
increase into the 3000 to 3500 J/kg range. Thunderstorm development
will be likely during the mid to late afternoon along a zone of
low-level convergence from northern Missouri into central and
eastern Iowa. Additional storms are expected to form further north
into parts of far eastern Minnesota and western Wisconsin. RAP
forecast soundings in the late afternoon from eastern Iowa into
southwest Wisconsin have curved hodographs, with 0-6 km shear near
40 knots, and 0-3 km storm-relative helicity around 225 m2/s2. This
environment will support supercells with tornado potential. A strong
tornado or two will be possible as supercells move eastward in a
strengthening low-level jet during the late afternoon and early
evening. Large hail and wind damage will also be possible with
supercells. From this cluster, a second severe line segment with
damaging wind gusts is expected to develop. This line will likely
impact parts of northeast Missouri and north-central Illinois.
Further southwest across parts of northwest/north-central Missouri
and northeast Kansas, scattered thunderstorm development is expected
during the late afternoon and early evening. These storms will be
located near an axis of strong instability, along which RAP
forecasts suggest that 0-6 km shear will be in around 40 knots. In
addition 700-500 mb lapse rates are forecast to be near 7.5 C/km.
The environment should support large hail and severe wind gusts.
...Ohio Valley/Central Appalachians...
A moist and unstable airmass will be in place today across much of
the region, with surface dewpoints in the lower to mid 70s F.
Although large-scale ascent will be weak, isolated thunderstorms
appear likely to develop in areas where low-level convergence
becomes maximized. Forecast soundings across the Ohio Valley show
steep low-level lapse rates during the afternoon and have enough
deep-layer shear for a localized severe threat. A few of the
stronger cells could produce isolated severe gust and hail.
..Broyles/Lyons.. 06/10/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1245 AM CDT Wed Jun 10 2026
Valid 111200Z - 121200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
NORTHEAST MISSOURI...PARTS OF SOUTHERN AND EASTERN IOWA...SOUTHERN
WISCONSIN...NORTHERN AND CENTRAL ILLINOIS...NORTHERN INDIANA...PARTS
OF CENTRAL AND SOUTHERN LOWER MICHIGAN...AND FAR NORTHWEST OHIO...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK FROM THE SOUTHERN PLAINS INTO THE UPPER GREAT
LAKES...AND ACROSS THE MID-ATLANTIC INTO CENTRAL APPALACHIANS...
...SUMMARY...
Scattered to numerous severe storms capable of potentially strong
tornadoes, large hail greater than two inches in diameter, and
destructive winds with gusts in excess of 75 mph appear likely from
portions of the lower Missouri and mid Mississippi Valleys into the
upper Great Lakes. Widely scattered severe storms capable of
damaging winds and large hail are possible across the Southern
Plains, as well as the Mid-Atlantic into central Appalachians.
...Synopsis...
A potent short-wave trough initially over the central High Plains
Thursday morning is forecast to accelerate through the upper Great
Lakes with a trailing perturbation moving through the central Plains
into mid MS Valley Thursday night. Both disturbances will be located
on the cyclonic aside of an unseasonably strong mid-level jet with
500-mb wind speeds of 60-80+ kt. Elsewhere, northwest flow pattern
will prevail in the mid levels across the Mid-Atlantic, with a
series of weaker disturbances moving through that region.
At the surface, low pressure initially over north-central KS
Thursday morning will develop into central lower MI by Thursday
night. The surface low will be developing along a composite
outflow-warm front that will be rapidly lifting north through the
Midwest into the upper Great Lakes. Meanwhile, a trailing cold front
will advance southeast through the lower MO and mid MS Valleys, with
the southwestward extension of the boundary settling south into the
southern Plains.
...Mid/lower Missouri Valley into the Mid Mississippi Valley and
upper Great Lakes...
There is good model agreement that a cluster of severe storms,
including supercells, will be ongoing at 12z Thursday across the mid
MO Valley, immediately northeast of the surface low and within a
zone of strong, low-level warm advection. The early-day storms are
expected to grow upscale into an organized MCS with embedded
supercell and bowing structures across IA by mid to late morning
amidst a rapidly destabilizing air mass, which will be coincident
with strong low-level and deep-layer shear. As such, the potential
for tornadoes (some strong) and corridors of destructive winds in
excess of 75 mph is expected to increase significantly during the
morning. The intensifying MCS and its related destructive wind and
tornado threat is expected to move into southern WI and northern IL
by early to mid afternoon, and eventually into lower MI by late
afternoon into evening.
An additional wave of supercells and/or bowing structures is
expected to develop along the trailing outflow from the lead MCS, as
well as along the cold front from eastern IA and northern IL into
the mid MS Valley during the afternoon into evening. Those storms
will be capable of tornadoes, large to very large hail, and damaging
winds with significant gusts, which could become widespread should
storm mode transition to a bowing line.
...Eastern Kansas into the Southern Plains...
Thunderstorm development is anticipated by mid to late afternoon
along the cold front amidst a moderate to strongly unstable air
mass. The models indicate the strongest deep-layer shear remaining
within the post-frontal environment. Nonetheless, there is some
signal for 30-40 kt of effective bulk shear to cross the eastern KS
and western MO segment of the front at an oblique angle, which will
be supportive of supercell storm modes with a risk for large to very
large hail and severe wind gusts. Deep-layer shear vectors are
forecast to align largely parallel with the front across the
southern Plains, which may contribute to downshear storm seeding,
leading to more messy modes. Nonetheless, the degree of instability
will favor vigorous up/downdrafts capable of large hail and damaging
winds.
...Mid-Atlantic into central Appalachians...
Daytime heating coupled with dewpoints in the 60s to low 70s are
expected to yield a weakly capped and moderate to strongly unstable
afternoon air mass. Forcing for ascent associated with the
disturbances mentioned in the synopsis are expected to foster
multiple clusters of thunderstorms capable of damaging winds,
especially if organized cold pools can develop. There is some model
signal that a corridor of slightly stronger low-level and deep-layer
shear will materialize across the lower Hudson Valley Thursday
afternoon, which would support some potential for supercells capable
of large hail and perhaps a brief tornado.
..Mead.. 06/10/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0225 AM CDT Wed Jun 10 2026
Valid 121200Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MID-ATLANTIC INTO CENTRAL APPALACHIANS...
...SUMMARY...
Scattered severe storms capable of damaging winds and some large
hail are possible across the Mid-Atlantic into Central Appalachians
Friday afternoon and evening.
...Synopsis...
A short-wave trough over the upper Great Lakes and OH Valley Friday
morning will progress through southwest Ontario to along the St.
Lawrence Valley, with a corridor of height falls and stronger
mid-level winds overspreading the lower Great Lakes into
Mid-Atlantic. At the surface, a cold front will move through the
lower Great Lakes and central Appalachians before merging with lee
troughing east of the northern and central Appalachians.
...Mid-Atlantic into Central Appalachians...
A hot and moist air mass is expected to exist across the pre-frontal
warm sector Friday afternoon with temperatures in the upper 80s to
upper 90s and dewpoints in the 60s to low/mid 70s. While mid-level
lapse rates are expected to remain modest, the high theta-e boundary
layer will largely contribute to moderate instability. The glancing
influence of the short-wave trough coupled with convergence along
the cold front and lee trough, in addition to terrain influences are
expected to foster scattered to numerous thunderstorms through the
peak of the diurnal heating cycle.
The strongest vertical shear of 30-40 kt is forecast from the lower
OH Valley into the lower Great Lakes, where the potential will exist
for some transient supercell and bowing structures capable of large
hail and damaging winds. Vertical shear will be comparatively weaker
along the lee trough; however, both low-level lapse rates and
instability will be greater, supporting potential for damaging
downburst winds and marginally severe hail. There is some model
signal that storms will coalesce into multiple clusters by late
afternoon into early evening with a potentially more concentrated
area of damaging winds reaching the Mid-Atlantic Coast.
...Mid-South into the Central and South High Plains...
Moderate to strong instability is forecast south of the surface
front, which is expected to stall across the discussion area. In the
absence of appreciable forcing for ascent, the models vary on the
location and coverage of diurnally enhanced storms, which could pose
some severe-weather threat. Severe-weather probabilities may
eventually be added to some of the area once confidence in storm
evolution becomes more clear.
..Mead.. 06/10/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0326 AM CDT Wed Jun 10 2026
Valid 131200Z - 181200Z
...DISCUSSION...
...Day 4/Saturday...
The models are in generally good agreement in depicting a prominent,
mid/upper-level low over Ontario with a secondary, weaker low or
short-wave trough across the northern Rockies. A belt of enhanced,
westerly winds in the mid levels will reside to the south of those
features from the northern Plains through the Great Lakes. At the
surface, an area of low pressure is forecast across the central
Plains with an associated front extending northeast into the upper
Great Lakes.
A strongly unstable air mass is forecast ahead of the front across
portions of the mid/lower MO Valley into Ozark Plateau with
instability decreasing with northeastward extent into the upper
Great Lakes. The models indicate sufficiently strong deep-layer
shear across the frontal zone to support organized storm modes,
including supercells. Highest confidence in greater storm coverage
and an associated severe-weather threat remains centered on the
mid/lower MO Valleys. Severe-weather probabilities may need to be
extended into the upper Great Lakes in subsequent outlooks.
...Day 5/Sunday...
A number of the deterministic models indicate a short-wave trough
and associated jet streak moving through the Great Lakes into
Northeast, within the base of the Ontario upper low. Farther west,
the northern Rockies short-wave trough will advance toward the
central Rockies. At the surface, a cold front associated with the
former disturbance mentioned above will progress through the
Northeast and OH Valley, with the western extension of the boundary
stalling across the southern Plains.
The models indicate a narrow axis of modest instability developing
by afternoon ahead of the front from the northern New England to the
upper OH Valley, where the strongest vertical shear is forecast.
Some severe weather appears possible in those areas; however, the
limited extent of the warm sector leads to uncertainty in the
coverage and duration of any threat.
Greater instability and a wider warm sector are forecast with
southwestward extent from the OH River and TN Valley into southern
Plains. Generally weak vertical shear is forecast across the frontal
zone, which should limit the degree of storm organization. A
possible exception is across the southern and central High Plains,
where an easterly low-level wind component will boost deep-layer
shear to some extent. Model trends will be monitored for the
possible inclusion of severe-weather probabilities in that area.
...Day 6/Monday...
The deterministic models are in reasonably good agreement in
amplifying the aforementioned short-wave trough over the central
Plains with an associated belt of enhanced mid-level flow extending
through the OH Valley into Northeast. At the surface, there is some
signal that an area of low pressure could develop along a front
across the southern Plains into Ozark Plateau. Some severe-weather
threat appears possible in that area, as well as along the front
that is expected to stretch east through the TN Valley into the
Carolinas. Predictability in the specific details are too low to
include an area.
...Days 7-8/Tuesday and Wednesday...
The ensemble mean solutions are in relatively good agreement in
suggesting the central Plains short-wave trough will become absorbed
into broader-scale trough amplification east of the MS Valley. At
the surface, it appears that a frontal wave will move from the TN
Valley toward the Mid-Atlantic coast, while a trailing cold front
advances into the Gulf Coast states. While areas of severe weather
are possible during this time frame, predictability in their
location is low.
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