By Robin Culverwell

By Robin Culverwell

PHILADELPHIA (CBS) — All eyes are on Thursday’s forecast, with the US Open in town and storm weather on the horizon (see related story).

Rain and strong thunderstorms are familiar adversaries for Delaware Valley residents this time of year, but we could be targeted by a bigger problem tomorrow: a derecho (pronounced deh-RAY-cho).

“It’s a flowery term for a long-lived line of very strong thunderstorms,” explains Accuweather meteorologist John Feerick.  “Usually it tracks over several hundred miles, and usually it has winds of in excess of 80, 90 miles an hour in some cases.”

Derechos trigger “straight line” winds, but Feerick says tornadic activity is always a possibility with warm, moist air.

Another concern, he notes, is flooding, after the deluges of both last Friday and Monday.

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