Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Wed Jul 01 2026
Valid 011200Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST INTO THE UPPER GREAT LAKES...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS AND THE NORTHEAST...
...SUMMARY...
Scattered severe thunderstorms are forecast across the Upper
Midwest/Great Lakes today and tonight. Damaging wind gusts (some to
80 mph) are the main concern, in addition to isolated large to very
large hail and a few tornadoes. Additional severe storms are
possible across parts of the the central High Plains and Northeast.
...Midwest and Upper Great Lakes ...
Within a belt of strong midlevel southwesterly flow extending from
the central/northern Plains into the Upper Midwest/Great Lakes, a
convectively augmented midlevel impulse should be the focus for
ongoing/morning strong-severe storms over parts of southern MN and
vicinity. This activity will mainly pose a risk for damaging gusts
and possibly large hail. These storms should continue
developing/spreading east-northeastward into the Upper Midwest along
a stationary boundary, where diurnal heating of a moist air mass and
steep lapse rates will lead to strong surface-based buoyancy. This,
combined with around 40 kt of effective shear, will favor a mix of
supercells and organized clusters. Scattered damaging wind gusts,
large to very large hail, and a few tornadoes will all be possible.
Thereafter, high-resolution guidance is in general agreement,
depicting a second round of upstream thunderstorm development during
the afternoon/evening in the vicinity of southern MN -- likely in
response to a strengthening low-level jet and related isentropic
lift. Similarly, these storms should spread east-northeastward
through a strongly unstable air mass and 40-50 kt of effective shear
(with increasing clockwise-curved hodographs). Swaths of damaging
winds (some gusts near 80 mph possible), large to very large hail,
and a few tornadoes will be possible.
...Central 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 air
mass. A mix of loosely organized clusters and possibly some
supercell structures will be capable of producing severe wind gusts
and large hail.
...Northeast...
Enhanced west-northwesterly midlevel flow will persist across the
Northeast, where a warm/moist air mass will contribute to around
3000 J/kg MLCAPE. 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)
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...
Along the southern periphery of a midlevel anticyclone centered over
the central Appalachians, a belt of 20-30-kt east-southeasterly flow
in the 700-500-mb layer will overspread a hot/moist air mass with
4500 J/kg MLCAPE during the afternoon. Despite limited deep-layer
shear, the extreme buoyancy and well-mixed boundary layer will be
favorable for wet microbursts with the stronger convective clusters
that evolve.
...Northern Rockies/High Plains...
Isolated to widely scattered thunderstorms are expected ahead of a
slow-moving midlevel trough moving across the Northwest. Preceding
the trough, around 40 kt of midlevel 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.
..Weinman/Chalmers.. 07/01/2026
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