Derechos are aggressive thunderstorms with high winds that can cause destruction similar to tornadoes. The Storm Prediction Center Web page describes derechos thusly:
Widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to that of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term "straight-line wind damage" sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles and includes wind gusts of at least 58 mph then the event may be classified as a derecho.
And just how likely is it that a derecho will hit New York? Tough to tell. Meteorologist John Hart told Bloomberg,“There is no way to have high confidence in such a forecast. We decided the risk of that scenario happening was high enough that we would highlight it.”
Governor Cuomo issued a statement urging New Yorkers to prepare for the potential storms. For tips on how to remain safe, visit the governor's site.
In June, a fierce derecho swept through the DC area causing extensive power outages and killing multiple residents.
See below for the damage from June's derecho: