Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1115 AM CDT Sat Sep 20 2025
Valid 201630Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTH-CENTRAL PLAINS...
...SUMMARY...
Scattered strong to locally severe thunderstorms may impact parts of
the south-central Plains this afternoon and evening, accompanied by
an isolated threat for strong to severe wind gusts and marginally
severe hail.
...South-Central Plains...
Visible-satellite imagery late this morning shows a couple of small
thunderstorm clusters over parts of the Ozarks into northeast OK and
mostly clear skies farther west and southwest over OK into the TX
Panhandle. Surface analysis places a zone of outflow extending from
west-central AR northwestward into north-central OK. The primary
front arcs from the OK Panhandle vicinity northeastward into
central/eastern KS. A moist and moderately unstable airmass is
forecast by mid-late afternoon across the Marginal Risk.
A relatively non-descript upper pattern, north of a flattened upper
ridge, features a couple of very minor perturbations slowly moving
east across the central High Plains into the mid MS Valley, to the
south of more amplified disturbances over the upper MS Valley and
ND. Weak capping and the aforementioned seasonably moist airmass
will favor isolated to scattered thunderstorms developing near the
front and outflow late this afternoon into the evening. Diurnal
steepening of low-level lapse rates may yield an isolated risk for
localized severe gusts and perhaps marginally severe hail. This
activity will likely diminish by mid evening owing to the loss of
heating.
...Upper Midwest/Great Lakes...
An upper trough centered near the IA/WI/MN/IL border will continue
to slowly migrate east across WI/northern IL today. Similar to
areas farther southwest over the south-central Plains, a seasonably
moist will undergo some heating in areas void of thicker cloud cover
and aid in 1000 J/kg MLCAPE developing over WI according to forecast
soundings. Weak 0-6 km shear (i.e., < 20 kt) should temper updraft
organization and limit storm intensity. Nonetheless, a couple of
strong gusts or small hail may occur with the more vigorous storms
this afternoon.
..Smith/Wendt.. 09/20/2025
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