Anatomy of an MCS: A 24 hour + weather odyssey

Call it the big little storm that could.

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Sunday night’s MCS (Mesocale Convective System) that tore through Minnesota with high winds & heavy rain is still going strong late Monday….in West Virginia!

Check out the time line & progress of the now 24 hour + old MCS. You can see a really cool 24 hour animated high res radar loop here.

2pm Sunday: Bismarck, North Dakota

The radar image below shows the developing thunderstorm cluster near Bismarck, North Dakota Sunday afternoon. Note the storms are still cellular in nature and not yet organized into a “bow echo’ structure. The storms produced an EF-2 tornado near Napoleon, ND Sunday.

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T-Storm cluster developing into MCS near Bismarck, ND Sunday.

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Damage near Napoleon, ND Sunday.

11pm Sunday: Twin Cities

Two distinct bow echoes are now racing through central and southern Minnesota including the Twin Cities Sunday night.

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Bow echoes racing though the Twin Cities Sunday night.

Twin Cities NWS storm reports

10 AM Monday: Chicago & Northern Indiana

One massive, well organized “classic” bow echo structure is now crossing Lake Michigan into northern Indiana and southwest Lower Michigan after barreling through Chicago. The storms produced extensive wind damage and even a rare seiche on Lake Michigan!

From Chicago NWS:

“During the morning hours of July 11, 2011, a line of severe thunderstorms moved very quickly across northern Illinois and southern Lake Michigan, producing widespread wind damage. In addition, the strong thunderstorm winds with this system generated a classic seiche event on the lake. A seiche is a situation where lake water ahead of the storms is piled up along the downstream shore (in this case Indiana and Michigan) and then sloshes back and forth across the lake for several hours. The danger from a seiche comes from rapidly rising and falling lake levels, which can damage watercraft along the shoreline, sweep people off piers and breakwaters, and pull swimmers far away from shore.”

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Classic bow echo crossing Lake Michigan into Indiana Monday morning.

5:46pm EDT: West Virginia

The same MCS is now producing a bow echo in Pennsylvania and West Virginia and turning to the right with upper level steering winds as it rambles southeast.

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Bow echo “turning right” and diving southeast into West Virginia Monday afternoon.

Let’s see how long this MCS lasts.

Enjoy our fabulous weather in the meantime!


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