Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Mon Aug 31 2026
Valid 311300Z - 011200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER PARTS OF THE GREAT LAKES REGION...THE CENTRAL
PLAINS...AND THE GREAT BASIN....
...SUMMARY...
Isolated severe storms will be possible mainly later this afternoon
into tonight across the Upper Midwest/upper Great Lakes, the central
Plains, and across the lower Colorado River Valley and Great Basin.
...Great Lakes Region...
Water vapor imagery shows a subtle shortwave trough moving across
NE. This feature is forecast to track northeastward through the day
and affect the Great Lakes region by late afternoon. Relatively
strong heating is expected across much of WI, along with dewpoints
in the upper 60s to lower 70s. This along with moderately steep
mid-level lapse rates will yield afternoon MLCAPE values over 2500
J/kg. A cold front will sag into the region by early evening,
providing the focus for widely scattered thunderstorms from central
WI into upper MI. This activity will track east-southeastward
across WI and into lower MI. Forecast soundings suggest sufficient
vertical shear to support rotating storms capable of locally
gusty/damaging winds and perhaps some hail.
...Eastern CO into NE...
A persistent plume of mid-level moisture continues to affect areas
from AZ into CO, with another round of afternoon thunderstorms
expected over the mountains. As these storms spread eastward into
eastern CO, strong outflow winds may accompany the more intense
cores. Isolated strong storms may persist into parts of northwest
KS and much of NE after dark.
...UT/AZ...
A shortwave trough over CA will track eastward and provide
large-scale forcing for ascent today over parts of AZ/UT. This will
result in scattered thunderstorms once again this afternoon across
much of UT and northern AZ. If pockets of sufficient heating can
develop, locally damaging wind gusts could occur.
..Hart/Broyles.. 08/31/2026
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