National Weather Service Derecho Watch and 9 Things You Must Do in a Storm

The National Weather Service in Indianapolis is looking out for a possible “Derecho” pattern to develop across Central Indiana.

Ever hear the term “derecho” and wonder what it means?

“Derechoes are large clusters of thunderstorms that produce widespread wind damage, usually as a result of one or more curved lines of thunderstorms known as bow echoes.

This word in Spanish means “straight” and these windstorms leave wide, long and straight line damage. These winds can be as strong as 50 to 100 mph.

“An ordinary thunderstorm produces damaging winds usually only a mile or two wide and a few miles long, but derechoes can produce damage of tens of miles wide and several hundred miles long, said Dr Greg Forbes.”

Derechoes are the most active during the late spring and summer unlike tornadoes which are more common in the spring, forecasters are watching an outbreak of severe weather from Illinois to Maryland, one meteorologist predicted it would be a “multi billion dollar storm” causing massive power outages.

These storms are forecast to start in Illinois on Wednesday afternoon, bringing tornado threats from there through Indiana and into Ohio.

Meteorologists say conditions could be conducive for those storms to strengthen into a massive line packing up to 70 mph winds, large hail and heavy rain. Some storms could cross over the Appalachians and reach Maryland overnight Wednesday into Thursday.

Storm warning

“It looks like the highest threat of severe weather will be across northern Illinois and northern Indiana, although southern Wisconsin might not see as much,” said Steven Hentz, meteorologist at the National Weather Service in Sullivan.

“Thursday begins with some uncertainty regarding the fate of a meso scale convective system affecting the Ohio valley tonight. It is unclear what the strength of this system will be at the beginning of Thursday,” a meteorologists wrote in a National Weather Service forecast discussion for the Baltimore/Washington region.

“By late afternoon or evening, the storms are expected to organize into a squall line and may possibly grow into a derecho,” the weather service’s eastern region headquarters wrote on Facebook. “The squall line will move into the central Appalachians and possibly the mid Atlantic region overnight. While the storms are expected to be weakening during the overnight hours, severe weather will still be possible.”


“Simulated radars suggest after 2 pm. the storms develop and start as super cells and quickly become a squall line with damaging wind gusts,” he wrote. Super cells are massive thunderstorms with tall clouds that contain a rotating updraft of wind and often bring tornadoes

9 Things you Must do during a Storm

1. Postpone outdoor activities.
2. If you are driving, try to safely exit and park. Stay in the vehicle until the heavy rain ends.
3. Take shelter in a strong building and get out of mobile homes.
4. Shutter windows and close outside doors securely.
5. Avoid electrical equipment including telephones, TV’s and radios.
6. Listen to local news and watch for the signs outside.
7. Do not take a bath or use plumbing.
8. If outside, avoid high ground, water, trees and metal objects such as fences.
9. The National Weather Service recommends staying inside at least 30 minutes after thunderstorm.

Written by Edgar Soto

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