Frigid temperatures this weekend prompt cold weather advisories

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A widespread convectively induced straight-line windstorm.

Specifically, the term is defined as any family of downburst clusters produced by an extratropical mesoscale convective system. Derechos may or may not be accompanied by tornadoes. Such events were first recognized in the Corn Belt region of the United States, but have since been observed in many other areas of the midlatitudes.

Johns, R. H., and W. O. Hirt 1987. Derechos: Widespread convectively induced windstorms. Wea. Forecasting. 2. 32-49.

This looks like a bumpy overnight and early Wednesday AM for folks along the I-90 corridor.

An overnight Mesoscale Convective System (MCS) is likely to develop in South Dakota and roll along I-90 through southern Minnesota overnight. Most of the storms should occur after midnight. Storms may rumble through the Twin Cities early Wednesday AM, but the biggest severe threat appears to be focused on southern Minnesota.

The T-Storm complex looks potentially severe...and may form a "Derecho"...a long lasting bow shaped cluster of severe storms notorious for producing widespread straight line wind damage.

Damaging winds may approach 60 to 100 mph in some areas with the overnight storms.

NOAA's SPC has put out slight and moderate risk areas for parts of South Dakota into southern Minnesota overnight into early Wednesday.

Here's some attention getting wording from NWS.

And some concern from the Twin Cities NWS in the late Tuesday forecast discussion.

June and July are prime derecho season in the Upper Midwest. Here's a look at derecho "climatology" in the summer months.

Minnesota is prone to derechos and has had some famous storms like the

Minnesota may not be in the heart of tornado alley...but there is a pretty strong frequency signal for derechos in Minnesota. We spend our summers near the edge of the "Bermuda High" and derechos like to run the edge of the developing heat dome.

Early studies noted how these long-lived damaging wind storms showed up as a "bow echo" on radars. Heres' a look at the anatomy of these storms.

Bottom Line: People in southern Minnesota should be alert for damaging T-Storm clusters overnight. Keep the NOAA Weather Radio on and handy...and be ready if you need to take shelter overnight.

“Derecho” Pattern: Damaging wind event possible along I-90 corridor overnight

Go Deeper.

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