RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0306 PM CDT Wed Jul 01 2026
Valid 012000Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE UPPER MIDWEST INTO THE GREAT LAKES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST...CENTRAL HIGH PLAINS...AND GULF COAST STATES...
...SUMMARY...
Multiple rounds of severe thunderstorms are still expected across
the Upper Midwest and Upper Great Lakes into tonight. A couple of
tornadoes are possible but damaging wind gusts are expected to be
the more widespread hazard, in addition to isolated large to very
large hail. Severe storms also remain a concern across parts of the
central High Plains, Northeast, and Southeast/Tennessee Valley.
...20Z Update...
The main change made to this outlook was to expand the wind-driven
severe probabilities southward across portions of the Upper Midwest
based on observational trends. A belt of relatively thick cloud
cover exists across portions of the Midwest. However, considerable
clearing and a CU field, along with isolated thunderstorms, has
developed across eastern IA into southern WI, where appreciable
buoyancy (2000-3000 J/kg MLCAPE) and up to 40 kts of effective bulk
shear reside. Furthermore, a few of the latest WoFS runs also depict
some higher thunderstorm coverage across eastern IA into southern
WI. As such, the thinking is that organized severe potential, mainly
in the form of severe gusts, should exist across this region through
the evening.
Otherwise, the previous forecast remains on track, with relatively
minor changes made to the thunder and severe probabilities to
reflect the latest observations and guidance consensus.
..Squitieri.. 07/01/2026
.PREV DISCUSSION... /ISSUED 1156 AM CDT Wed Jul 01 2026/
...Midwest and Upper Great Lakes...
An active multi-round day of severe weather is expected across the
region through tonight. Early this afternoon, ongoing severe risks
will continue to focus across northern Michigan as well as eastern
Wisconsin, with a secondary round of severe storms potentially
spreading into Lower Michigan later this afternoon. See existing
Mesoscale Discussions/Watches for short-term details.
Severe potential later today will focus on a convectively reinforced
boundary, with a very moist and potentially unstable environment
along and south of it. Renewed deep convective development is
expected later this afternoon into tonight across northern Iowa and
southern Minnesota, and again into Wisconsin. A ribbon of moderately
strong mid-level westerlies, some of it MCV-enhanced, will support
organized storm modes including supercells and fast-moving line
segments and potential upscale-MCS development. Large to very large
hail will be possible with the more intense storms in addition to
wind, which may become more prevalent of a hazard (60-80+ mph) as
storm mergers lead to a couple of strong to severe clusters
developing. Some tornado potential may exist as well, particularly
along the effective boundary and/or increasing this evening as a
southwesterly low-level reinvigorates.
...Central and southern 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
airmass. A mix of loosely organized clusters and possibly some
supercell structures will be capable of producing severe wind gusts
and large hail. Farther south into the southern High Plains, weaker
flow will limit overall storm organization, but steep lapse rates
will support severe gusts with the more intense downdrafts.
...Northeast...
Enhanced west-northwesterly mid-level flow will persist across the
Northeast, where a warm/moist air mass will contribute to around
3000 J/kg MLCAPE, especially across much of New York and
Pennsylvania. 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
quantitatively) 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/Tennessee Valley...
Along the southern periphery of a mid-level anticyclone centered
over the central Appalachians, easterly flow through much of the
troposphere resides atop a hot/moist air mass with 3000-4000 J/kg
MLCAPE this afternoon. 12z observed soundings from Atlanta,
Birmingham, and Jackson MS notably sampled 25-35 kt winds between
3-6km AGL, which could aid in storm organization this afternoon. A
somewhat cooler thermal profile aloft was also noted with the 12z
Atlanta sounding with a relatively steep mid-level lapse rate
profile. Strong to severe pulse thunderstorms are expected
regionally, and seemingly with a somewhat greater coverage and
likelihood than a typical pulse-type scenario. The stronger
water-loaded wet microbursts will yield localized gusts of 50-65 mph
and be capable of wind damage.
...Montana and northern Great Basin...
Isolated to widely scattered thunderstorms are expected ahead of a
slow-moving mid-level trough moving across the Northwest. Preceding
the trough, around 40 kt of mid-level 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.
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Wed Jul 01 2026
Valid 031200Z - 041200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN AND CENTRAL PLAINS INTO MIDWEST...
...SUMMARY...
Isolated to scattered severe storms are possible from the
northern/central Plains into the Midwest, Tennessee Valley, and
Mid-Atlantic on Friday.
...Synopsis...
One or multiple mid-level disturbances over the northern and central
High Plains Friday morning are forecast to progress into the upper
Midwest by Friday night. Meanwhile, a downstream belt of west to
west-northwest flow will prevail in the mid levels from the Great
Lakes into Northeast. At the surface, a lee cyclone and attending
trough will exist over the northern High Plains with a secondary low
pressure center over the central Plains. An outflow-modulated warm
or stationary front is expected to extend from the northern Plains
low into the upper Midwest. Elsewhere, there is some model signal
for the development of a surface trough from southern New England
into the Delmarva Friday afternoon.
...Northern and Central Plains into the Midwest and Upper Great
Lakes...
The potential for early-day storms introduces forecast uncertainty
in subsequent afternoon/evening severe weather potential due to the
location of relevant surface boundaries and extent of convective
overturning. However, by afternoon, the models indicate the
development of a broad corridor of moderate to strong instability
across the northern and central Plains into the southern Great Lakes
and OH Valley. Diurnally enhanced thunderstorm development is most
probable from the vicinity of the northern Plains lee cyclone and
trough east along the outflow-modulated front within a zone of
forcing for ascent preceding the disturbances mentioned in the
synopsis. The instability combined with modestly strong deep-layer
shear will be supportive of organized storm modes capable of large
to very large hail and damaging winds with the potential for
significant gusts Friday afternoon into night.
...Mid-Atlantic...
Increasing height falls are forecast Friday afternoon into night
downstream from a more prominent short-wave trough progressing into
eastern Ontario and southwest Quebec. The various 12Z models offer
different scenarios in the preferred location of diurnally enhanced
storms with the best overlap extending from portions of southern NY
and northern PA to the Mid-Atlantic Coast. The colocation of
moderate instability and modest deep-layer shear in that area may
support some storm organization with the primary hazards being
damaging winds and large hail.
A similar environment is forecast across the region on Saturday,
July 4th, potentially warranting the inclusion of higher severe
weather probabilities.
...Ohio and Tennessee Valleys...
A number of models indicate the potential for one or multiple MCSs
to progress through the region during the forecast period. Vertical
shear is expected to be relatively weak. However, the presence of
moderate to strong instability may promote periods of cold-pool
organization with a related damaging wind threat.
..Mead.. 07/01/2026
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