198
ACUS01 KWNS 041254
SWODY1
SPC AC 041253

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0753 AM CDT Sat Oct 04 2025

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS FAR
SOUTHEAST WY...FAR NORTHEAST CO AND THE NE PANHANDLE...

...SUMMARY...
Isolated severe wind gusts/hail may accompany the stronger
thunderstorms across the central Rockies into the northern High
Plains late this afternoon and evening.

...Central Rockies to northern Plains...
Current satellite imagery shows an upper low moving into western UT
within broadly cyclonic upper flow from the western CONUS into
northern/central Plains. This upper low is forecast to devolve into
an open wave while continuing northeastward within the broad
troughing, reaching the northern Plains by early tomorrow morning.
Moderate to strong mid-level flow will persist throughout the
eastern periphery of this wave, spreading eastward from the central
Rockies and across the northern/central Plains into the Upper
Midwest.

Recent surface analysis shows lower pressure across the Plains ahead
of the upper low. A cold front was also analyzed from southeast
Manitoba southwestward across the central Dakotas and southern WY to
another low in southwest WY. Pressure gradient between these lower
pressures over the Plains and the high over the Mid-Atlantic will
support gusty southerly winds across the Plains and Mid/Upper MS
Valley. Even with this moderate southerly flow, low-level moisture
along and ahead of the cold front will remain modest, offset by
strong boundary-layer heating and resultant mixing. This should keep
much of the northern and central Plains free of thunderstorms
throughout the day.

Some daytime thunderstorms are likely across the central Rockies,
closer to the upper low and stronger large-scale ascent. These
storms are expected to progress northeastward towards a warmer and
more mixed airmass over southeast WY/northeast CO/NE Panhandle
during the late afternoon/early evening. A few stronger gusts are
possible as these ongoing storms interact with the deeply mixed
boundary layer over the area. The cold front will be near this
region as well, with some gust enhancement possible due to frontal
circulations as well.

Later into the evening, a strengthening low-level jet and resulting
warm-air advection will aid in thunderstorm development north of the
front, most likely from northern SD into eastern ND/northwest MN.
Cooling mid-level temperatures will help support moderate buoyancy
with MUCAPE around 1000 J/kg. Moderate vertical shear will be in
place as well, with the resulting environmental conditions
supportive of occasional updrafts capable of producing hail.

..Mosier/Bentley.. 10/04/2025

$$