Jul 11, 2011
A complex of severe thunderstorms rolled across Nebraska, Iowa, Wisconsin, Illinois, Michigan and reached as far as Ohio this afternoon. These storms originated in Nebraska Sunday evening and moved into Iowa ahead of a shortwave trough.
The storms became a full fledged bow-echo (typically shown on Doppler radar) across the Wisconsin/Illinois border traveling over 60 mph. The Chicago, Illinois area was hit hard with strong winds that damaged trees, downed powerlines and reports of structural damage had occurred across the region. As a result, power outages exceeded over 700,000 during the height of the storm.
Further north into Wisconsin, the comma head of the storm system produced strong winds for a longer period of time including higher rainfall totals. The damage though was not as significant compared to the Chicago area. The lack of more widespread damaged may have been attributed to an outflow boundary moved south from earlier storms across Central Wisconsin in the early morning hours which may have helped stabilized the atmosphere somewhat across the Milwaukee area.
The storms moved east across Michigan, Indiana and Ohio with more reports of wind damage. The storms finally weakened near West Virginia. This mesoscale convective complex is known as a derecho which is defined as a long lasting windstorm that travels over many states causing damage in it's path.
Storm Photos & Reports:
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