RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Tue Jun 09 2026
Valid 091200Z - 101200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...
...SUMMARY...
Numerous severe thunderstorms with a potential for 60 to 80 mph
winds with locally higher gusts, along with tornadoes (some
potentially strong), and large to very large hail are expected to
develop in parts of the central and northern Plains from this
afternoon into tonight. Severe wind gusts and hail will also be
possible from north-central and west-central Kansas southwestward
into the Texas Panhandle.
...Central and Northern Plains...
An upper-level trough will move eastward across the western U.S.
today. Ahead of the system, mid-level heights will fall over the
central and northern Plains. At the surface, a moist airmass will be
in place over the Great Plains, with a dryline located from far
western North Dakota southward into western Nebraska. To the east of
the dryline, surface dewpoints will be in the upper 60s and lower
70s F. As surface temperatures warm today, an axis of moderate
instability is expected to develop over the central Dakotas.
Thunderstorms will form near and to the east of the dryline in the
mid afternoon. Strong low-level convergence near the instability
axis will result in a relatively rapid transition to linear mode
with a large MCS expected to develop during the late afternoon and
early evening. The severe MCS will move eastward across the central
and eastern Dakotas, with the southern part of the line located in
central Nebraska.
Late afternoon RAP forecast soundings in the central Dakotas near
the instability axis have MLCAPE in the 4000 to 5000 J/kg range with
0-6 km shear between 30 to 40 knots. Low to mid-level lapse rates
are forecast to be in the 7 to 8 C/km range. This will be very
favorable for large hail and severe wind gusts. Hailstones greater
than 2 inches in diameter and wind gusts above 80 mph will be
possible with supercells early, and along the more intense parts of
the line as it develops.
Concerning the tornado threat, a mid-level jet will become
juxtaposed with a low-level jet in the late afternoon across central
and northern North Dakota. Storms that can remain discrete for a few
hours after initiation will have potential to become supercells and
produce tornadoes. The strongest low-level shear is forecast in
northeastern North Dakota, where RAP forecast soundings increase 0-3
km storm-relative helicity into the 250 to 300 m2/s2 range by early
evening. This will be favorable for a few strong tornadoes. Further
south from central South Dakota into Nebraska, there will be
potential for supercells with tornadoes near gaps in the line. The
threat for strong tornadoes may be greatest in the early to mid
evening as the line interacts with a 45 to 55 knot low-level jet
from far southeastern South Dakota southward into eastern Nebraska.
From late evening into the early overnight period, the severe threat
associated with the severe MCS is expected to gradually downtrend as
it moves into the upper Mississippi Valley.
...North-central and Western Kansas/Texas and Oklahoma Panhandles...
At mid-levels today, heights will fall within southwesterly flow
over the southern and central High Plains. At the surface, a moist
and unstable airmass will be located over much of the region. By
afternoon, a focused zone of maximized low-level convergence is
forecast to develop. This axis will move eastward toward the western
edge of the stronger instability, with thunderstorms forming in the
mid to late afternoon. Near the axis, MLCAPE is forecast to be
around 2000 J/kg with 0-3 km lapse rates near 8 C/km. In addition,
surface temperature-dewpoint spreads will be large, which will be
favorable for severe wind gusts in the late afternoon and early
evening.
...Upper Mississippi and Lower Ohio Valleys...
A mid-level ridge will move eastward toward the upper Mississippi
and lower Ohio Valleys today. Ahead of the ridge, moderate
instability will be in place by afternoon. Scattered thunderstorms
that form within this moist and unstable airmass will have potential
for isolated severe gusts, mainly as low-level lapse rates become
steep in the afternoon.
..Broyles/Thornton.. 06/09/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Tue Jun 09 2026
Valid 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER EASTERN
MINNESOTA...MUCH OF WISCONSIN...CENTRAL AND EASTERN IOWA...AND
NORTHWEST ILLINOIS...
...SUMMARY...
Scattered to numerous severe thunderstorms capable of large hail in
excess of two inches in diameter, a few strong tornadoes, and
damaging winds with gusts in excess of 75 mph appear likely across
portions of the upper Mississippi Valley and Midwest Wednesday
afternoon into night. More sporadic occurrences of large hail and
damaging winds are possible into the central and southern Plains,
and from the lower Great Lakes toward the Mid-Atlantic coast.
...Synopsis...
An upper low along the MT-SK border Wednesday morning is forecast to
deepen while redeveloping to along the ND-MB border Wednesday night.
That intensification process will be driven by mid/upper-level jet
streaks moving through the base of broader-scale trough, in tandem
with an amplifying short-wave trough. A lead disturbance initially
over the northern High Plains Wednesday morning will accelerate
northeast into the Upper MS Valley by evening, along with the
leading edge of stronger mid/upper-level jet streak winds.
At the surface, an area of low pressure over eastern SD Wednesday
morning will develop north-northeast into southeast MB by evening,
while a trailing cold front advances through the upper MS Valley
into the upper Great Lakes. The trailing extension of the boundary
from the mid MO Valley into KS will move more slowly through the day
before stalling and then lifting north Wednesday night in response
to cyclogenesis over the central Plains. A dryline will intersect
the front over southwest KS Wednesday afternoon, with that feature
extending southwest into western TX.
...Upper Mississippi Valley/Upper Great Lakes into the Central and
Southern Plains...
Areas of thunderstorms may be ongoing Wednesday morning across
portions of MN and WI, aided by warm advection along a nocturnal
low-level jet. Residual convective outflow boundaries from the
early-day storms and the approaching cold front are expected to
focus the most intense thunderstorm development, which may occur by
early afternoon across northern and central parts of MN. Subsequent
south/southwestward storm development is expected by mid/late
afternoon along and ahead of the front from southern MN and western
WI through central/eastern IA, northern MO, into eastern/southern
KS, and perhaps into western OK and northwest TX.
Rich boundary-layer moisture, characterized by dewpoints in the
upper 60s to low/mid 70s will coincide with a plume of steep
mid-level lapse rates to yield moderate to strong afternoon
instability with MLCAPE increasing to 2000-4000+ J/kg across the
warm sector. Deep-layer shear will strengthen through the afternoon
into evening with the arrival of the jet streaks, especially across
the upper MS Valley into upper Great Lakes where effective bulk
shear magnitudes of 50-60 kt are forecast.
The expected CAPE-shear combination will support numerous severe
storms that begin as supercells capable of large to very large hail
and some tornado threat, with an eventual transition to a more of a
cold-pool-driven convective system with embedded bowing structures
by evening across portions of the Upper Midwest, potentially into
Great Lakes. Damaging wind potential, including the possibility for
75+ mph wind gusts would likewise increase with that mode
transition, as would a continued tornado threat with line-embedded
meso-vortices. The greatest potential for a few strong tornadoes is
expected to develop with any sustained supercells across portions of
eastern MN, WI, eastern IA, and northwest IL in the proximity of a
strengthening low-level jet, which will enhance near-ground shear.
Storms are expected to be increasingly more isolated in nature with
southwestward extent along the front and dryline from eastern KS
into western OK and northwest TX. Nonetheless, the degree of
instability coupled with around 30 kt of deep-layer shear will favor
organized multicell and/or supercell structures capable of large
hail during the afternoon and evening hours.
A separate large-hail threat is expected to develop Wednesday night
into Thursday morning over the mid MO Valley within a zone of strong
warm advection and moisture flux occurring within the terminus of a
50+ kt low-level jet.
...Lower Great Lakes to Mid-Atlantic Coast...
Forcing for ascent associated with a weak mid-level disturbance
moving through the region is expected to foster widely scattered
thunderstorm development during the afternoon amidst a moist and
moderately unstable air mass. Model soundings indicate some
enhancement of the mid-level wind field, with deep-layer shear
increasing to around 30 kt in some areas. As such, a few severe
storms appear possible with an associated risk for damaging wind
gusts and large hail.
..Mead.. 06/09/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Tue Jun 09 2026
Valid 111200Z - 121200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
MISSOURI THROUGH EASTERN IOWA...NORTHERN AND CENTRAL ILLINOIS AND
SOUTHERN WISCONSIN INTO WESTERN LOWER MICHIGAN...
...SUMMARY...
Scattered to numerous severe storms capable of potentially strong
tornadoes, large hail, and destructive winds appear likely from
portions of the lower Missouri and mid Mississippi Valleys into the
upper Great Lakes. More sporadic occurrences of damaging wind and
large hail are possible across the southern Plains, upper Ohio
Valley and lower Great Lakes toward the Mid-Atlantic Coast.
...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 approaching 70-80 kt. The 00z models have slowed
the progression of the mid-level wave, as well as the associated
surface low, which is forecast to develop from northeast KS along
the synoptic front or remnant outflow from overnight storms into
southern WI by afternoon and northern lower MI or the UP by Thursday
night.
...Lower Missouri Valley/Mid Mississippi Valley into the Upper Great
Lakes...
A very moist boundary layer will combine with steep mid-level lapse
rates to yield a moderate to strongly unstable air mass by afternoon
to the south of the composite surface boundary. A cluster of mainly
elevated thunderstorms is expected to be ongoing Thursday morning
across portions of the mid MO Valley, to the northeast of the
surface low. Those storms are expected to become progressively more
surface-based and intense by mid to late morning into afternoon
while rapidly moving northeast, coincident with the surface low.
Forecast sounding within the inflow environment of those storms
indicate strong low-level and deep-layer shear, supportive of
supercells and bowing segments capable of potentially strong
tornadoes, in addition to large hail and damaging winds.
Additional severe storms are expected to develop along the trailing
front from the lower MO and mid MS Valleys southwest through the
Ozarks into southern Plains. The progressive nature of the mid-level
system suggests the potential for long-tracked supercells and bowing
structures capable of tornadoes and swaths of destructive winds.
...Upper Ohio Valley and Lower Great Lakes to the Mid-Atlantic
Coast...
While large-scale forcing for ascent is expected to remain
relatively weak, model guidance indicates scattered, afternoon storm
development from the lee of the lower Great Lakes through the
central Appalachians to the vicinity of a lee trough in the
Mid-Atlantic. Vertical shear is expected to remain relatively weak;
however, the presence of a moist and moderately unstable air mass
will support wet microburst activity and an associated risk for
sporadic damaging winds.
..Mead.. 06/09/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Tue Jun 09 2026
Valid 121200Z - 171200Z
...DISCUSSION...
...Day 4/Friday...
The last several deterministic model runs have consistently shown
the progression of a short-wave trough and associated 50 kt jet
streak from the OH Valley into the St. Lawrence Valley, with
meaningful height falls as far south as the Mid-Atlantic. At the
surface, the northern portion of a cold front initially from
southwest Ontario to near the confluence of the MS and OH Rivers and
into the southern Plains will progress southeast and eventually
merge with a trough stretching from southern New England to the
Carolina Piedmont. Ahead of the front, boundary-layer dewpoints in
the 60s to low/mid 70s will combine with modestly steep mid-level
lapse rates, especially across the lower Great lakes, to yield a
moderately unstable air mass by afternoon.
Initial storms are anticipated across the lower Great Lakes into
upper OH Valley by early afternoon, with activity advancing east
toward the Hudson Valley, and southeast into the central
Appalachians and Mid-Atlantic through the remainder of the afternoon
into evening. The strongest vertical shear is forecast from the
lower OH Valley to the lee of the lower Great Lakes, where organized
storm modes capable of damaging winds and large hail appear most
probable.
Elsewhere, a more isolated severe-weather threat may materialize
within a low-level upslope regime in eastern NM.
...Day 5/Saturday...
The models are in generally good agreement in depicting a
mid/upper-level low over Ontario, and a positively tilted trough
from the northern Plains into the northern Rockies. A belt of
enhanced, westerly winds in the mid levels will reside to the south
of those features, from the northern and central Plains through the
Great Lakes. At the surface, the various ensemble members
consistently show the clustering of low centers over the central
High Plains with an associated surface front extending into the
upper Great Lakes.
Moderate to strong instability is forecast ahead of the surface
front from the central Plains into upper Great Lakes with more than
sufficient deep-layer to support higher-order storm modes. Highest
confidence in storm development Saturday afternoon and evening is
across the central Plains into mid/lower MO Valley from the vicinity
of the surface low northeast along the surface front.
Other more isolated severe storms appear possible along a weakening
front in the Carolinas.
...Day 6/Sunday...
The ensemble mean solutions depict lowering mid-level heights from
the central Plains into Great Lakes and OH Valley, in conjunction
with the gradual amplification of a long-wave trough located east of
the North American Rockies. More specifically, a number of the
deterministic models suggest a short-wave trough moving from the
northern into central Rockies, with another potentially more intense
mid-level system moving through the Northeast. An associated
surface front preceding both features may serve as the focus for
some severe-weather threat from the Northeast through the OH Valley
into the Southern Plains. However, there is considerable uncertainty
in finer-scale details, so no area will be highlighted.
...Days 7-8/Monday and Tuesday...
Further amplification of the long-wave trough is forecast with an
associated belt of mid-level flow extending from the central Plains
through the mid MS Valley into New England and the Mid-Atlantic.
Despite growing spread across the deterministic models, there is a
modest signal that the Day 6/Sunday central Rockies short-wave
trough will progress through the central Plains into mid MS Valley.
Some severe-weather threat could develop ahead of that disturbance
in the vicinity of the surface frontal system, should that scenario
unfold as advertised.
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