Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Thu Jul 24 2025
Valid 241300Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE GREAT LAKES INTO THE MIDWEST...CENTRAL/SOUTHERN PLAINS...AND
HIGH PLAINS...
...SUMMARY...
Locally damaging thunderstorm wind gusts will be possible from parts
of the Great Lakes to the central and southern Plains, mainly this
afternoon and evening. Isolated severe storms will also pose a risk
of hail and severe wind gusts over portions of the northern and
central High Plains.
...Synopsis...
Modestly enhanced westerly mid-level flow will be maintained today
between an upper trough progressing slowly eastward over central
Canada and the north-central CONUS, and upper ridging across the
Southeast and Mid-Atlantic. Multiple mid-level MCVs evident on
satellite and radar should move generally east-northeastward across
parts of the Midwest and Great Lakes today. At the surface, a
convectively reinforced front will be draped from Ontario/Quebec
southwestward to the southern Plains. This front will likely serve
as a focused for additional scattered to numerous thunderstorms this
afternoon and evening, some of which could become strong to severe
on an isolated basis.
...Great Lakes into the Midwest and Central/Southern Plains...
A moist and rather unstable airmass will exist along/ahead of the
front today, as diurnal heating aids in the gradual steepening of
low-level lapse rates. Stronger mid-level flow and related
deep-layer shear should be present across parts of MI and vicinity.
Some enhancement to the low/mid-level winds and modest ascent
associated with an MCV over northeast WI this morning may also aid
in thunderstorm development and organization downstream into parts
of northern Lower MI by early afternoon. This area appears to have
the best combination of forecast instability and shear, and any
thunderstorms which can form here could become severe while posing a
threat for both isolated hail and damaging winds. However, low-level
flow along/near the front is generally expected to remain veered to
southwesterly, which should limit low-level convergence to some
extent. Therefore, confidence in overall coverage of severe
convection remains too low to include greater severe probabilities
across northern Lower MI at this time.
Mid-level flow and effective bulk shear values will decrease with
southward extent across the Midwest into the southern Plains, away
from any remnant MCV influences. This should tend to limit updraft
organization with thunderstorms that develop this afternoon across
these regions. Still, some potential should exist for loosely
organized clusters given the linear low-level forcing. And with
steep low-level lapse rates and moderate to strong instability, some
of this convection may be capable of producing strong to locally
severe winds through the early evening hours before eventually
weakening with the loss of daytime heating.
...High Plains...
Moderate instability should develop across parts of the
northern/central High Plains this afternoon. Large-scale ascent will
be weak behind a departing mid-level shortwave trough. Even so,
convective development should occur near the adjacent higher terrain
this afternoon. Effective shear of 25-40 kt will support some
updraft organization. Initially discrete cells may pose an isolated
threat for hail. Some outflow amalgamation/mergers could eventually
occur, with a threat of strong to locally severe gusts spreading
eastward into the evening before convection eventually weakens.
Farther south across portions of the southern High Plains, scattered
to numerous thunderstorms are also expected to develop this
afternoon/early evening. Deep-layer shear will remain weak across
this region, but localized strong to severe outflow gusts may still
be possible.
..Gleason/Grams.. 07/24/2025
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