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 Sun Jun 28 2026
Valid 281200Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE DAKOTAS
AND NORTHWEST MINNESOTA...AND ACROSS NORTHERN IOWA AND VICINITY...
...SUMMARY...
Severe thunderstorms are possible today across northern Iowa and
vicinity, and mainly tonight across the Dakotas. Large to very large
hail and severe winds are the primary hazards.
...Dakotas to IA/WI through tonight...
As the primary cyclone occludes near the southwest SK/southeast AB
border, a belt of south-southwesterly midlevel flow near 50 kt will
be maintained from CO to the Dakotas, east of the broad closed low
over the northern Great Basin/Rockies. A separate lee cyclone is
expected to form in the vicinity of northeast CO this afternoon and
then progress northeastward across NE/SD overnight. A storm cluster
will likely be ongoing near the southwest MN/northwest IA border at
the start of the period, as a continuation of the ongoing storms
along the NE/SD border. These morning storms will pose a threat for
occasional large hail/wind damage along the warm front/buoyancy
gradient through midday/early afternoon. In the wake of the morning
storms, a surface warm front demarcating boundary-layer dewpoints
into the 70s will likewise move northward slowly across IA into
southern MN/WI. West of the morning storms, a warm elevated mixed
layer observed in 00Z soundings across the central Plains will act
to cap the moistening boundary layer and likely inhibit additional
warm sector storm development through much of the period. A few
storms will be possible in ND during the afternoon, though storm
coverage/intensity are both in question given weak-moderate buoyancy
and limited forcing for ascent.
Much of the severe threat will likely be delayed until tonight
immediately north of the lee cyclone into SD. Westward advection of
richer moisture and ascent preceding the surface cyclone (and subtle
embedded speed maxima aloft) will likely support elevated
thunderstorm development overnight across western SD into southern
ND. The environment will favor elevated supercells capable of
producing very large hail (2-3 inches in diameter) and occasional
severe gusts.
Farther east, a zone of low-level warm advection will be focused
across WI by late evening/early tonight along the northeast edge of
the warm elevated mixed layer. Sufficient moistening above the
surface and large CAPE will favor the potential for at least
isolated large hail/strong gusts with largely elevated storms
tonight.
...Carolinas/southern VA this afternoon/evening...
An MCV now over KY will turn more southeastward today, downstream
from an amplifying ridge over the lower and middle MS Valley.
Destabilization and steepening of low-level lapse rates in cloud
breaks, along with ~25 kt midlevel flow, will support isolated wind
damage potential with storm clusters during the afternoon/evening.
...West TX late this afternoon/evening...
Strong surface heating and deep mixing along a sharpening dryline
will allow high-based thunderstorm development from late afternoon
through late evening. Flow aloft will be weak, but inverted-V
profiles will favor isolated severe outflow gusts of 60-75 mph.
..Thompson/Chalmers.. 06/28/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Sun Jun 28 2026
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN PORTIONS OF
THE NORTHERN AND CENTRAL PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Severe thunderstorms are possible from parts of the central/northern
Plains into the Upper Midwest on Monday. Large hail and severe winds
are the primary concerns, though a couple of tornadoes may also
occur.
...Synopsis...
A compact shortwave trough will evolve out of the upper trough in
the northern Rockies. The timing of this feature remains a bit
uncertain. The strongest mid-level ascent will likely occur in
eastern Dakotas/western Minnesota after 00Z. A surface low will
deepen within the eastern Dakotas and lift north-northeast with
time. A very moist airmass will be in place between a cold front in
the central Plains and a warm front in the Upper Midwest. Upper
level ridging will continue in the Midwest/East with modest
breakdown of this ridge expected in the Dakotas/Minnesota.
...Eastern Dakotas into northern Minnesota...
The forecast remains rather uncertain across these regions. At least
weak convection appears probable within parts of the Dakotas into
western Minnesota during the morning. How this activity evolves will
play a role in where afternoon severe potential will exist. Model
agreement has marginally increased with regard to the evolution of
the shortwave trough in the northern Plains and the surface low
migrating north-northeast near the Red River. Even so, upper-level
ridging that will persist through much of the period limits
confidence in if and how many storms will develop during the
afternoon/early evening. Should sufficient destabilization occur
near the surface low, a portion of eastern North Dakota into
northwest Minnesota appear to have the greatest relative potential
for severe storms. All severe hazards would be possible given the
50+ kt of effective shear, 4000+ J/kg MLCAPE, and locally stronger
low-level shear. Model solutions for activity near the surface low
and areas southward into eastern South Dakota and western Minnesota
are highly disparate. The ECMWF would suggest some potential for an
MCS to develop near the surface low and track through parts of
northern/east-central Minnesota along the buoyancy gradient. This
particular scenario has been fairly consistent along with the
depiction of a more southern surface low/upper trough. Solutions
such as the RRFS would suggest a supercell or two could occur
farther south along the South Dakota/Minnesota border.
...Nebraska into southern/central Minnesota...
Though the timing of development differs, there has been an
increasing convective signal trend in recent guidance along the cold
front. There is at least some potential for this to occur during
late afternoon with a window for storms to be surface based, but it
is more probable that it occurs after dark when the low-level jet
increases. Large hail could occur early in the convective cycle, but
deep-layer shear parallel to the boundary should mean a quick
transition into linear structures. Severe wind gusts will likely be
the primary concern, though a low-end tornado threat may exist given
the stronger low-level jet.
..Wendt.. 06/28/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Sun Jun 28 2026
Valid 301200Z - 011200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Severe thunderstorms will be possible from parts of the central High
Plains into the Upper Midwest on Tuesday.
...Upper Midwest...
Though the primary shortwave trough will be lifting into Canada, a
remnant cold front will be situated across parts of northern
Wisconsin into Minnesota. Strong to extreme buoyancy will be present
south of this boundary. A belt of moderate mid-level flow will
promote 40-45 kt of effective shear within the warm sector.
Mid-level ascent will generally be weak. Where convection can
initiate on the mesoscale, damaging winds and large hail may occur.
There is some potential that an MCS could develop given the
substantial buoyancy, but it is not clear where the preferred
corridor for that will be at this time.
...Northeast Colorado into southwest Nebraska...
A modest shortwave trough will move into the central Rockies. A
surface low is expected to develop in eastern Colorado. This will
draw low-level moisture into parts of the High Plains. Given around
40 kt of effective shear, supercells capable of large hail and
severe gusts would be possible. Low-level shear will also be
enhanced near the surface low and a tornado or two could also occur.
...Northeast...
Given the upper-level pattern, strong convection could be occurring
in Canada and move southeastward around the upper ridge. Depending
on the timing/intensity of this potential activity, severe
probabilities may be needed in future outlooks. Confidence remains
low at this time, however.
..Wendt.. 06/28/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Sun Jun 28 2026
Valid 011200Z - 061200Z
...DISCUSSION...
Relatively little change is expected in the upper-level pattern from
mid to late this week. A broad trough in the West will bring
southwesterly flow across the Rockies and parts of the Plains. In
the East, an upper ridge will persist. During the weekend, models
are in general agreement that the upper ridge will flatten and
broaden across the southern U.S. This pattern will favor the
maintenance of a very moist airmass within parts of the Plains into
the Midwest and Southeast. The lack of more notable mid-level and
surface features decrease predictability with regard to where severe
convection may occur. That being said, subtle surface
boundaries/shortwave troughs may promote convective development each
day within parts of the Plains/Midwest. Trends in model guidance
will continue to be monitored, but confidence remains low in placing
severe probabilities.
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