Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 AM CDT Tue Jun 24 2025
Valid 241300Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN AND CENTRAL HIGH PLAINS...
...SUMMARY...
Storms associated with very large hail and severe wind gusts will be
likely this afternoon and evening in parts of the central and
northern High Plains. Marginally severe storms will be possible this
afternoon from part of the central and northern Plains eastward into
the Northeast.
...Synopsis...
Early morning satellite imagery shows an expansive upper ridge over
much of the eastern CONUS, and upper troughing across the Great
Basin vicinity. A northern-stream shortwave trough currently over SK
is forecast to progress quickly eastward through MB and ON, leading
to some dampening of the eastern CONUS ridge. Several convectively
augmented vorticity maxima are also expected to move through the
northern and central High Plains ahead of the more substantial
shortwave trough moving across the Great Basin. This evolution will
lead to some dampening of the northwestern periphery of this ridge
as well.
Like the upper pattern, the surface pattern is currently dominated
by eastern CONUS ridging, with an ill-defined frontal zone between
the warm and moist airmass under the ridge and a more continental
airmass across the northern Plains and Upper MS Valley. Recent
surface analysis places a low over western KS with a stationary
boundary extending northeastward from this low to another low over
WI. A more progressive cold front extends northeastward from the WI
low through central ON. The moist airmass (i.e. dewpoints in the
70s) south of this boundary will destabilize with daytime heating,
and scattered thunderstorm development is anticipated amid modest
low-level convergence during the afternoon from the central Plains
through the Great Lakes region into the Northeast. Vertical shear
will be weak, limiting storm strength/organization and contributing
to an outflow-dominant storm mode. Damaging gusts will be possible
with any of the stronger line segments. Greater severe potential is
expected across the northern and central High Plains (discussed
below).
...Northern/Central High Plains...
Post-frontal southeasterly upslope flow is anticipated across the
region today, helping to offset diurnal mixing and keep dewpoints in
the upper 50s/low 60s this afternoon. The increased low-level
moisture and strong heating will foster airmass destabilization by
the early afternoon, with scattered to numerous thunderstorm
expected. Initiation is expected over the higher terrain before then
moving northeastward into the lower elevations. Vertical shear will
be strong enough to support supercells initially capable of
producing large to very large hail. A trend towards more
outflow-dominant structures is anticipated with time, with one or
more line segments capable of strong to severe gusts developing.
This outflow-dominant character is forecast to limit the tornado
threat, but a locally enhanced threat may exist from southeast WY
into the southern NE Panhandle and far northeast CO where the best
overlap between low-level moisture and southeasterly surface winds
is expected.
...Southern Rockies...
Increasing low to mid-level moisture will support numerous to
widespread thunderstorms across the southern Rockies today. Very
shear will be weak, promoting a mostly disorganized multicellular
mode.
..Mosier/Leitman.. 06/24/2025
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