RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1154 AM CDT Mon Jun 29 2026
Valid 291630Z - 301200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
MINNESOTA...
...SUMMARY...
Severe thunderstorms are expected today across the Dakotas, Upper
Midwest and Middle Missouri Valley, including damaging winds, large
hail and a few tornadoes this afternoon through tonight.
...Dakotas/Mid-Missouri Valley/Upper Midwest...
Of short-term focus/concern, is a long-lived storm cluster across
north-central Minnesota that has begun to grow upscale again to the
north of a warm front. Damaging winds and large hail will be
prominent concerns this afternoon, and tornado potential may
increase particularly with southern flank development near the warm
front. For additional short-term details, see Mesoscale Discussion
1379.
Later this afternoon, a very moist airmass will become very unstable
over parts of the central Plains into the Upper Midwest, including
recovery in the wake of the early day storm complex across
Minnesota. While lesser instability is expected north-northwestward
into North Dakota, more modest buoyancy and long hodographs will
support severe storms. Isolated to scattered thunderstorms are
forecast by afternoon/early evening as large-scale ascent associated
with the approaching upper wave overspreads the region. Ample
deep-layer shear coupled with the large buoyancy will favor
supercells. Large to very large hail, a couple of tornadoes, and
severe wind gusts will be possible with this surface-based activity,
especially as storms grow upscale this evening and progress
into/across parts of Iowa/Minnesota.
...Kansas/Oklahoma/Texas...
Isolated high-based thunderstorms are possible near the dryline.
Moderate instability is expected within this region with generally
weak deep layer shear. Strong evaporatively cooled downdrafts will
be capable of severe wind gusts with the more intense cores.
...Southern Appalachians and parts of Georgia/Florida...
Strong to locally severe storms capable of downbursts will be
possible within a moist/unstable environment this afternoon, with
some degree of storm organization possible as aided by a modestly
stronger belt of northeasterly flow aloft.
..Guyer/Supinie.. 06/29/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 PM CDT Mon Jun 29 2026
Valid 292000Z - 301200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PARTS OF
EASTERN NORTH DAKOTA AND NORTHWESTERN MINNESOTA...
...SUMMARY...
Severe thunderstorms are expected today across the Dakotas, Upper
Midwest and Middle Missouri Valley, including damaging winds, large
hail and a few tornadoes this afternoon through tonight.
...20Z Update...
The most noteworthy change with this update was the addition of
10-percent tornado probabilities (with CIG1) over parts of eastern
ND into northwestern MN. Here, the latest surface observations and
visible satellite imagery indicate a warm front moving slowly
northward. In the wake of an earlier MCS, diurnal heating of a moist
air mass (lower 70s dewpoints) and steep midlevel lapse rates should
yield sufficient boundary-layer recovery for the development of
surface-based storms ahead of a surface low tracking northward
across the Dakotas this afternoon and evening. Related strong
buoyancy (3000-4000 J/kg MLCAPE) and increasingly large
clockwise-curved hodographs (200-300 m2/s2 effective SRH) near the
boundary will support a locally favorable corridor for a few
supercell tornadoes (some of which could be strong).
..Weinman.. 06/29/2026
.PREV DISCUSSION... /ISSUED 1154 AM CDT Mon Jun 29 2026/
...Dakotas/Mid-Missouri Valley/Upper Midwest...
Of short-term focus/concern, is a long-lived storm cluster across
north-central Minnesota that has begun to grow upscale again to the
north of a warm front. Damaging winds and large hail will be
prominent concerns this afternoon, and tornado potential may
increase particularly with southern flank development near the warm
front. For additional short-term details, see Mesoscale Discussion
1379.
Later this afternoon, a very moist airmass will become very unstable
over parts of the central Plains into the Upper Midwest, including
recovery in the wake of the early day storm complex across
Minnesota. While lesser instability is expected north-northwestward
into North Dakota, more modest buoyancy and long hodographs will
support severe storms. Isolated to scattered thunderstorms are
forecast by afternoon/early evening as large-scale ascent associated
with the approaching upper wave overspreads the region. Ample
deep-layer shear coupled with the large buoyancy will favor
supercells. Large to very large hail, a couple of tornadoes, and
severe wind gusts will be possible with this surface-based activity,
especially as storms grow upscale this evening and progress
into/across parts of Iowa/Minnesota.
...Kansas/Oklahoma/Texas...
Isolated high-based thunderstorms are possible near the dryline.
Moderate instability is expected within this region with generally
weak deep layer shear. Strong evaporatively cooled downdrafts will
be capable of severe wind gusts with the more intense cores.
...Southern Appalachians and parts of Georgia/Florida...
Strong to locally severe storms capable of downbursts will be
possible within a moist/unstable environment this afternoon, with
some degree of storm organization possible as aided by a modestly
stronger belt of northeasterly flow aloft.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1219 PM CDT Mon Jun 29 2026
Valid 301200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
WISCONSIN AND THE UPPER PENINSULA OF MICHIGAN...PARTS OF NEW YORK
AND VERMONT...AND THE CENTRAL PLAINS...
...SUMMARY...
Severe thunderstorms will be possible from parts of the central High
Plains into the Upper Midwest, and across parts of the Northeast on
Tuesday.
...Northeast...
Enhanced northwesterly flow aloft on the northeastern periphery of
an amplified upper ridge will overspread the region on Tuesday. This
area will also be on the southerly periphery of a strengthening
southwesterly low-level jet oriented across Ontario/Quebec. This
will support effective shear magnitudes around 40+ kt. Supercell
structures will be possible, but most guidance suggests convection
will develop into one or more forward propagating clusters/bowing
segments. Damaging wind gusts will be the main hazard with this
activity as it moves across a very moist and moderately unstable
airmass. Given supercell wind profiles and enlarged, favorably
curved hodographs, a couple of tornadoes also will be possible,
especially if a more semi-discrete storm mode occurs. While details
in convective evolution vary some among various guidance, a
consistent signal exists (particularly across northern NY into VT)
and a Slight risk (Level 2 of 5) has been included. Convection
should gradually decrease in intensity with southeast extent toward
southern New England and the Mid-Atlantic vicinity as instability
decreases and inhibition increases.
...Upper Midwest/Great Lakes...
An upper low and attendant shortwave trough initially over the
Canadian Prairies and northern MN will gradually shift
east/northeast through the period. Height tendencies will generally
be neutral across the area given the strong upper ridge just to the
east. Enhanced southwesterly deep-layer flow will persist across the
region, with some intensification of a low-level jet by late
afternoon/evening. At the surface, a quasi-stationary boundary is
forecast to extend from near the MN Arrowhead, southward into
eastern NE at midday. To the south/east of the boundary, a very
moist airmass with 70s dewpoints is forecast. A corridor of strong
to extreme instability is depicted by some model guidance across
northern WI into the U.P. of Michigan. Convection may develop near
the surface boundary and shift east across northern portions of the
Great Lakes. If this occurs, damaging winds (some near 80 mph) could
accompany thunderstorm clusters potentially organizing into a bowing
MCS.
Some guidance develops additional convection overnight across parts
of southern MN/WI into northern IA and vicinity. This activity would
be supported by a warm front lifting northward across the central
Plains and Mid-MO Valley and an intensifying southwesterly low-level
jet. While ample instability will exist across the area, it is
uncertain if this activity would be surfaced-based. Nevertheless, a
favorable thermodynamic and kinematic environment would support some
severe wind/hail risk.
...Southern/Central High Plains...
Modest height falls are forecast as a midlevel shortwave impulse
ejected across the central Rockies into NE/SD from late afternoon
into the overnight hours. A surface trough/dryline will sharpen as a
result, and southerly low-level flow will transport low 60s
dewpoints northward along the boundary beneath steep midlevel lapse
rates. High-based convection is expected to develop by late
afternoon and shift east/northeast through evening. Initial
supercells could produce large to very large hail. With time, some
upscale development could occur via consolidating outflows and as
the low-level jet increases during the evening. This could bring an
increasing risk for damaging winds, a few possibly approaching 80
mph. Given a consistent signal across various CAMs, deterministic
and ML/AI guidance, a Slight risk (level 2 of 5) has been added.
...LA/MS/AL/GA/FL Panhandle...
Forecast guidance depicts 25-35 kt midlevel northeasterly flow on
the southern periphery of an upper high centered over the OH/TN
Valley. A very moist airmass will be present across much of the
region and strong destabilization is forecast amid strong daytime
heating. Forecast soundings depict around 20-30 kt effective shear
magnitudes, supporting some risk of organized cells/clusters.
Isolated damaging wind gusts are possible as activity develops
west/southwest through early evening.
..Leitman.. 06/29/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0200 PM CDT Mon Jun 29 2026
Valid 011200Z - 021200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND ACROSS THE
NORTHEAST...
...SUMMARY...
Isolated strong to severe storms will again be possible from the
central Plains into the Upper Midwest as well the Northeast on
Wednesday. Severe wind gusts and large hail are the main concerns.
...Synopsis...
The overall synoptic pattern will not changes much from Day
2/Tuesday into Day 3/Wednesday. The upper ridge over the eastern
U.S. may shift slightly east while an upper trough persists over the
West. A series of midlevel shortwave impulses will migrate across
the northern Plains and Upper Midwest/Great Lakes vicinity. Enhanced
mid/upper flow will persist from the Dakotas into the Great Lakes
and over the Northeast.
...Upper Midwest/Great Lakes...
A quasi-stationary boundary is forecast to extend from northern WI
toward southeast SD Wednesday morning. This boundary may slowly lift
northward during the afternoon. The evolution of this boundary will
largely be influenced by morning convection that may be ongoing
near/north of the boundary across parts of MN/WI at the beginning of
the period. Given a very moist airmass, strong to extreme
instability is forecast near and south of the boundary. Morning
convection could weaken as it lifts north of the boundary, or it
could intensify through the day as destabilization occurs, spreading
east across the Upper Great Lakes. Another round of convection may
develop during the late afternoon into the nighttime hours along the
boundary as well. While convective evolution is uncertain, the
thermodynamic and kinematic parameter space will support a risk for
severe wind gusts and large hail. Enhanced low-level shear near the
surface boundary could also result in a corridor of tornado
potential. Higher severe probabilities will likely be needed in
subsequent outlooks as mesoscale details and convective evolution
become more clear and forecast confidence increases.
...Northeast...
Large-scale ascent will not be as strong across the region on
Wednesday, though forecast guidance does show a shortwave impulse or
MCV moving across the area as it crosses the international border
from Canada. A very moist and strongly unstable airmass will be in
place and strengthening mid/upper northwesterly flow will support
some organized severe risk. However, storm coverage remains
uncertain. Strong downburst winds and isolated large hail will be
possible. The wind risk could increase if sufficient storm
coverage/interaction results in clustering/bowing segments, but this
scenario is uncertain given a lack of stronger low-level jet. Trends
will be monitored and higher severe probabilities may be needed in
subsequent outlooks.
...Central High Plains...
A surface trough will extend southward from western SD/NE into
eastern CO/NM on Wednesday. Southerly low-level flow will maintain
modest boundary layer moisture beneath steep midlevel lapse rates.
Southerly flow through around 500 mb will be somewhat weak, though
southwesterly flow increases substantially above that. This could be
sufficient for weakly organized convection developing within upslope
flow along the surface trough Wednesday afternoon/evening. Given
weaker instability and more modest vertical shear compared to
previous days, severe potential is more uncertain. However, strong
outflow gusts still appear possible given a deeply mixed boundary
layer and inverted-v sub-cloud thermodynamic profiles.
...Southeast...
Isolated to scattered thunderstorms are likely to develop on the
southern periphery of the upper anticyclone Wednesday afternoon. A
very moist and strongly unstable airmass will be in place, but
vertical shear appears a bit weaker compared to Day 2/Tuesday. Storm
coverage is uncertain, but some risk for locally strong gusts may
develop, especially if sufficient clustering can occur to promote
forward propagation.
..Leitman.. 06/29/2026
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