Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1125 AM CDT Mon Sep 22 2025
Valid 221630Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS...LOWER/MID MISSOURI VALLEY...AND OHIO
VALLEY...
...SUMMARY...
Scattered severe thunderstorms will be possible this afternoon into
tonight across portions of the southern/central Plains, lower/mid
Missouri Valley, and Ohio Valley. Large to very large hail and
severe/damaging winds should be the main threats.
...Synopsis...
Water-vapor imagery late this morning shows a mid- to upper-level
low and associated troughing over the Upper Midwest to the north of
a mid-level trough moving east across confluence of the OH-MS Rivers
and into the OH Valley. Additionally, a minor disturbance is moving
east across NE, a mid-level ridge extends from northern Mexico into
the central High Plains, and larger-scale troughing persists over
the West.
...Southern/Central Plains...
Little change in the forecast scenario for mainly tonight across the
central and southern Great Plains. A moist airmass characterized by
60s to lower 70s deg F dewpoints resides across OK northward into
NE-IA. Initially flattened mid-level ridging/neutral height change
will act to suppress thunderstorm development during the day and
perhaps into the early evening across the Great Plains. However, a
lead mid-level vort max ahead of the north-central Rockies trough,
will move across the Sangre de Cristos into the central High Plains
by early evening. The intensification of a southerly low-level jet
this evening and associated moist advection to the east of a weak
lee trough and surface low over the central High Plains, will favor
scattered thunderstorms eventually developing over the central High
Plains and in proximity to a frontal zone farther north in NE.
Ample buoyancy per forecast soundings and an elongated upper portion
of hodographs will support storm organization, including supercells.
Large to very large hail is a possibility with supercells this
evening into the early overnight over eastern NE and if cells can
develop ahead of an evolving thunderstorm cluster/MCS over northern
OK/southern KS. Severe gusts will likely become the primary hazard
later tonight but a risk for a brief tornado could develop with the
OK-KS activity given moist low levels and a linear mode.
...IA-WI...
Isolated to scattered storms are forecast to form along a front in
northern IA this afternoon/evening. With cool temperatures aloft and
modestly steepened mid-level lapse rates, this activity could pose a
threat for mainly severe hail given gradually strengthening westerly
winds with height through mid/upper levels.
...Tennessee/Ohio Valleys to the Lower Great Lakes...
A shortwave trough associated with ongoing convection over the
Mid-South/lower OH Valley this morning will translate northeastward
today across much of the OH Valley. Modestly enhanced southwesterly
low/mid-level winds will exist this afternoon over this region, with
20-30 kt of deep-layer shear supporting mainly loosely organized
multicells. Multiple clusters should develop and gradually
strengthen through the afternoon as they spread northeastward across
a weakly unstable airmass. Isolated to scattered damaging winds may
occur with the more intense portion of these thunderstorm clusters.
...Far Eastern Arizona into New Mexico...
Moisture remains limited this morning across eastern AZ and much of
southern/central NM, with surface dewpoints generally ranging from
the 40s to mid 50s. Westerly mid/upper-level flow across this
region is expected to gradually strengthen through the day as an
upper trough/low digs southward from the northern Rockies across the
Great Basin and towards the Four Corners region by late tonight. A
weak perturbation embedded within the mid-level westerly flow may
aid initial convective development this afternoon across the higher
terrain of east-central AZ and vicinity. This activity will spread
eastward across much of central NM through the remainder of the
afternoon and into the evening. While instability will likely remain
weak owing to limited low-level moisture, steepened low-level lapse
rates with daytime heating and moderate to strong deep-layer shear
should promote outflow-dominant convection with an isolated threat
for severe wind gusts.
..Smith/Wendt.. 09/22/2025
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