A large wall of thunderstorms coming from the Midwest for Washington D.C. tonight has could potentially spawn derecho, according to some forecasters.
Others say that while the storms will likely be dangerous, it will probably not reach derecho levels. New York City can expect a lot of rain and wind from a rare June Nor’easter, but we are outside of the predicted track of this specific storm system.
A derecho is a huge, fast moving storm that creates powerful winds and dumps enough water to drown cities and cause significant damage.
A derecho has to be at least 240 miles long and have winds of at least 58 miles per hour, but many can top 100 miles per hour. It brings not only rain and wind, but also hail, thunder, and lightning.
The fast-moving storms stack up on top of each other in bow shapes forming a serial derecho. When just one happens it’s called progressive.
Last June, a devastating 700-mile storm hit Washington DC, leaving 1 million homes without power. The forecast indicates this week’s storm could hit the same areas, though they probably won’t be as bad.
As the long line of storms cool the air around them forming clusters of cold air downbursts that spread horizontally and forces the warm, moist air around the storm to the leading edge. The warm edge causes more storms to form, which causes more cold air to flow down.
That’s the basics, but there is a lot that goes into the storm that we don’t fully understand, according to LiveScience:
While thunderstorms are relatively well-forecast, derechos are extremely difficult to predict. Meteorologists don’t fully understand all the subtle environmental factors that need to coalesce in order for a derecho to form.
In the United States, derechos are most common in the late spring and summer and there are typically one to three events each year.
For those of you wondering, the word is pronounced /dāˈrāCHō/ — DEH-REH-CHOH — basically just say it in a Spanish accent.
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