Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1239 AM CDT Mon Sep 08 2025
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN HIGH PLAINS...
...SUMMARY...
Isolated hail and damaging gusts are expected over portions of
western Kansas, northwest Oklahoma and the Oklahoma/Texas
Panhandles.
...Central/Southern High Plains...
Mean upper ridge is forecast to hold across the Rockies through the
day1 period, ensuring northwesterly flow persists across the High
Plains. Early this morning, water-vapor imagery depicted a notable
short-wave trough digging southeast across the central High Plains.
This feature is expected to advance into southeast NE/central KS by
late afternoon before advancing into MO/western AR by 09/12z. Partly
in response, LLJ should increase across the High Plains from the TX
Panhandle into south central NE, only veering into eastern KS late
in the period. As a result, low-level warm advection will focus
along a corridor from southern NE into northwest MO, ultimately
inducing one or more thunderstorm clusters along the nose of the
LLJ. Even so, instability may be a bit too weak to warrant much risk
for severe with this activity. Of more concern will be the strongly
destabilized regions of western KS into the TX Panhandle, where
low-level lapse rates will steepen due to strong boundary-layer
heating. Forecast soundings suggest convective temperatures will be
breached around 23z, and weak low-level convergence should prove
instrumental in convective initiation, as the aforementioned short
wave will have advanced downstream by this time period. While
large-scale forcing should be weak across this region, most HREF
members develop at least isolated convection. Adequate deep-layer
shear should be present for supercells and these storms will
propagate south with an attendant risk for large hail, locally
damaging winds, and perhaps a brief tornado or two. Greatest severe
risk will be late afternoon into the late evening hours.
...Upper MS Valley Vicinity...
Northern stream short-wave trough is forecast to dig southeast
across southern MB/ND into the upper Red River region by early
evening. This should aid LLJ that will increase across MN into the
U.P. of MI by 09/06z. Large-scale forcing favors elevated convection
along the nose of this jet, especially across the Arrowhead of
MN/Lake Superior. Have introduced a MRGL risk along the trailing
boundary across MN where steeper lapse rates may permit a few robust
updrafts to evolve shortly after peak heating. Even so, this
activity should be more isolated with the greatest concentration of
storms expected within the more favored warm advection zone.
..Darrow/Wendt.. 09/08/2025
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