ACUS01 KWNS 171255
SWODY1
SPC AC 171254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Wed Sep 17 2025

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
CO...NORTHEAST NM...AND THE WESTERN TX/OK PANHANDLES...

...SUMMARY...
Isolated severe thunderstorms are possible, mainly during late
afternoon to mid-evening, across parts of the south-central High and
Great Plains. The most likely corridor is from the Raton Mesa into
the western Texas and Oklahoma Panhandles, where large hail, severe
gusts, and a brief tornado are possible.

...Synopsis...
Early morning satellite imagery shows a broad cyclone centered over
WY and another more defined cyclone over the Mid-Atlantic. Modest
ridging exists between these cyclones from the southern Plains
through the Mid MS Valley and into the Upper Great Lakes. The
eastern cyclone is forecast to devolve into an open wave throughout
the day while gradually lifting northeastward. Several shortwave
troughs are forecast to rotate around the western cyclone while it
shifts eastward into more of NE/SD and deepens slightly.

Recent surface analysis reveals a weak front extending from a low
over the northern TX Panhandle north-northeastward to another weak
low over northwest KS and then more northeastward across central NE
into southwest MN. Portion of this front across KS and NE is
forecast to slowly push eastward/southeastward today while
consolidation into a more define and deeper surface low occurs
across northeast NE and southeast SD.

...South-central High Plains...
The shortwave trough currently rotating southward through western WY
is forecast to continue south/south-southeastward today. Lift
preceding this shortwave will contribute to thunderstorm development
within the buoyant post-frontal airmass across southeast CO and
northeast NM (in the Raton Mesa vicinity) during the late
afternoon/early evening. Slightly stronger mid-level flow will
accompany this shortwave as well, resulting in moderate deep-layer
vertical shear. Buoyancy will be modest, with the stronger buoyancy
anticipated ahead of the cold front, but the combination of buoyancy
and shear over the region should still be sufficient for organized
updrafts capable of large hail and damaging gusts. There is some
potential for this activity to interact with the western portion of
the cold front that is expected to arc back west/northwest across
the TX/OK Panhandles into far northeast NM/southeast CO. If this
occurs, the easterly surface winds and increased vorticity along the
boundary could result in a localized area of low-probability tornado risk.

...Southeast NE...Central/Eastern KS...Northwest OK...Eastern TX
Panhandle...

Showers and thunderstorms are ongoing along and ahead of the cold
front extending across the region. At least one MCV is noted within
this precipitation over far north-central KS. Cloud cover associated
with this precipitation will likely delay heating across much of KS
and NE, leading to some uncertainty whether the airmass will
destabilize ahead of the cold front later this afternoon.
Destabilization looks more probable from central KS across the
eastern TX Panhandle and northeast OK. This entire region will be on
the eastern periphery of the stronger mid-level flow, with the
modest shear supportive of some strong to severe storms capable of
damaging gusts and isolated hail in areas where the airmass destabilizes.

...IA and southern MN...
Forcing for ascent is expected to spread across the region from the
southwest as a shortwave trough rotates through the broader
troughing over the northern/central Plains. Like areas farther
southwest, cloud cover and limited diurnal heating results in
uncertainty regarding airmass destabilization. Even so, some
guidance shows strong heating, deep mixing, and destabilization
ahead of the approaching shortwave. This could result in some
high-based storm capable of damaging downbursts. However, the
overall conditionality of this scenario precludes introducing any
severe probabilities with this outlook.

..Mosier/Bentley.. 09/17/2025

$$
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