Valid 2026-10-12 12:00 UTC – 2026-10-13 12:00 UTC

NO SEVERE THUNDERSTORM AREAS FORECAST

No severe weather is expected Monday through Monday night.

Synopsis

A midlevel low initially over the Columbia Basin is forecast to progress south toward the Sierra Nevada, while an upper-level jet streak develops from the lower-CO Valley into the Upper Midwest. Ahead of the latter feature, a low-amplitude short-wave trough is projected to move from the northern High Plains into the Upper Midwest, embedded within a belt of 40-50 kt midlevel flow. In the low levels, an area of low pressure loosely related to the short-wave trough is expected to develop from the mid-MO Valley into the Upper Midwest along a stationary front. A cold front will trail southwest from that feature, linking with a secondary cyclone over the central High Plains.

Upper Midwest/Upper Great Lakes

A plume of relatively steep midlevel lapse rates of around 7 C/km will overlie the northern extension of a moistening boundary layer, supporting a corridor of moderate instability by afternoon to the south of the surface low and associated front described in the synopsis. Capping at the base of the lapse-rate plume/EML is likely to inhibit surface-based storm development in the warm sector. However, the 00Z models suggest that a cluster of elevated thunderstorms may persist Monday afternoon into night to the immediate north of the warm sector within a zone of forcing for ascent preceding the short-wave trough. While a few strong storms capable of small hail appear possible, marginal parcel buoyancy and only modest cloud-bearing shear are expected to limit the threat for severe weather.

Mead · 10/10/2026