RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Thu Jul 02 2026
Valid 021200Z - 031200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THE NORTHERN
PLAINS INTO PARTS OF THE UPPER GREAT LAKES AND MIDWEST AND OVER THE
SOUTHERN APPALACHIANS...
...SUMMARY...
Strong to severe storms will be possible from the northern Plains
into the Midwest and Great Lakes regions, as well as across the
southern Appalachians on Thursday. Isolated strong to severe storms
may also occur in the Tennessee Valley, central High Plains, and
parts of the Northeast.
...Synopsis...
The upper level pattern across the US will be characterized by
troughing across the western US with a high amplitude ridge across
the eastern US. Between these features, several shortwave troughs
will rotate through the flow across the central/northern Plains into
the Midwest. A surface low will be located across eastern Montana
into the western Dakotas, with a surface boundary extending from the
northern Plains into the Upper Midwest.
...Northern High Plains into the Great Lakes and Midwest...
Early morning convection is likely across some portion of North
Dakota in association with a vort max moving out of Montana. The
evolution of this activity will likely have implications on the
exact placement of the surface boundary by this afternoon across the
Dakotas. Afternoon thunderstorm development is expected near the
surface low and in the vicinity of the surface boundary/residual
outflow across the Dakotas by the afternoon. Coverage should
increase as a shortwave moves out of Montana into the
afternoon/evening with increasing forcing for ascent. Across the
northern High Plains, strong daytime heating amid steep low to
mid-level lapse rates will support moderate to strong instability.
This in combination with deep-layer shear around 40-45 kts will
support initial supercells capable of large to very large hail and
damaging wind. Through time, boundary parallel shear and large dew
point spreads promoting outflow dominate storms will likely support
one or more clusters/bowing segments moving south and east with
time, resulting in an increase in the damaging wind threat and
potential for a few significant gust 75+ mph.
...Southern Appalachians into the Tennessee Valley...
A very moist and unstable air mass is expected to be in place across
the Southern Appalachians into the Tennessee Valley this afternoon.
Widely scattered thunderstorms are expected to develop across the
high terrain, with tendency to cluster along outflows. Consensus is
highest across the Appalachians into the Tennessee Valley for a more
focused corridor of damaging wind potential.
...Central High Plains...
Isolated thunderstorms are expected to develop within the lee trough
across the central High Plains this afternoon. Moderate instability
overlapping with around 25-30 kts of deep-layer shear will support
potential for a mix of supercells and multi-cell clusters. Steep
low- to mid-level lapse rates and large temperature/dew point
spreads will support potential for severe gusts. Initial supercells
will pose potential for large hail.
...Northeast...
Northeasterly flow within the northern periphery of the eastern
ridge will allow for thunderstorm activity to track southward out of
Quebec/Ontario across portions of the Northeast this afternoon. The
presence of moderate to strong instability and 30-40 kt
of deep-layer shear will be supportive of organized storm modes with
the predominant hazard being damaging winds. Higher wind
probabilities and a level 2/Slight Risk may be needed with
additional outlook updates if a more favorable corridor of wind
potential become clearer.
..Thornton/Chalmers.. 07/02/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Jul 02 2026
Valid 031200Z - 041200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE BLACK
HILLS VICINITY INTO PARTS OF THE MIDWEST AND LOWER GREAT LAKES...
...SUMMARY...
Isolated to scattered severe storms are possible from the
northern/central Plains into the Midwest, Tennessee Valley, and
Mid-Atlantic on Friday.
...Synopsis...
Upper-level ridging will begin to flatten and spread westward on
Friday. Modest southwesterly flow aloft will continue across much of
the Rockies. In the East, stronger cyclonic flow aloft will continue
in New England and the northern Mid-Atlantic. A surface low will
deepen in parts of the central High Plains. A
quasi-stationary/outflow composite boundary will be situated within
the central/northern Plains into the Lower Great Lakes region.
...Black Hills vicinity into Mid-Missouri/Mississippi Valleys...
Forecast uncertainty remains with respect to how convection evolves
Thursday night into early Friday morning. Some convection could
linger in parts of South Dakota and possibly Nebraska. At the very
least, portions of the central/northern Plains will be impacted by
outflow from earlier convection. The position of the outflow will
determine where the greater severe threat develops during the
afternoon. Modest southwesterly flow aloft will drive the
development of the lee trough that will advect upper 50s to low 60s
F dewpoints into the High Plains. A subtle shortwave trough depicted
in most guidance will initiate convection within the higher terrain
of eastern Montana/Wyoming and the Black Hills. Initial supercells
will be capable of large to very large hail and severe winds.
Additional convection is also possible farther southeast along the
outflow boundary where a weak surface low may enhance low-level lift
of a weakly capped airmass. A similar threat for large/very large
hail and severe winds would accompany this activity. Should the
activity farther east remain discrete into early evening, a
marginally greater tornado risk would exist. Between these two zones
of convection, upscale growth will allow one or more MCS to develop
and track along the boundary. The lead MCS would have greater
potential for severe winds (some 75+ mph). The low-level jet
response during the evening will not be overly strong, but it should
be enough to help convection to continue into parts of Iowa later in
the evening.
...Northern Illinois into northwest Ohio...
With an MCV and related convection likely moving through the Great
Lakes region to the north, an outflow/theta-e boundary will settle
somewhere within these areas. Model guidance suggests that heating
along this boundary will promote scattered storm development. Modest
enhancement to deep-layer shear due to the MCV may allow for modest
organization of a cluster/linear segment that travels east along the
boundary. Wind probabilities have been increased to account for this
potential.
...Mid-Atlantic...
Model spread still exists as to where the greatest storm coverage
will exist during the afternoon. Temperatures nearing 100 F and 60s
F dewpoints will support strong destabilization across the region.
The degree of temperature-dewpoint spreads will promote efficient
downdraft production. Effective shear will be greatest in the
northern Mid-Atlantic where around 30 kt of flow at 500 mb will
exist. This should promote clusters/linear segments capable of wind
damage. Towards the Blue Ridge, storm coverage is much less certain
given the very weak forcing. Damaging downbursts are still possible
with storms that can develop. Model trends will continue to be
monitored for any increase in expected storm coverage.
...Tennessee Valley into Ohio Valley...
Strong heating of a mid/upper 60s F dewpoint airmass will promote
4000+ J/kg MLCAPE by the afternoon. Weak shear will limit storm
organization, but subtle shortwave troughs moving around the upper
anticyclone could allow for locally greater storm
coverage/clustering. Damaging downburst winds are the expected
hazard.
...Northern Plains into Upper Midwest...
Forecast uncertainty remains medium to high in terms of how much
destabilization will occur within these areas. Guidance generally
suggests convection/cloud cover will exist during the morning and
potentially parts of the afternoon. A broad marginal remains in
place for damaging winds and isolated large hail potential should
enough destabilization occur.
..Wendt.. 07/02/2026
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