Rare ‘Derecho’ Storm Forecast to Soak East Coast

A powerful storm that could turn into a rare “derecho” pounded the Midwest yesterday and is heading to the East Coast, threatening New York and the US Open golf tournament near Philadelphia.

A derecho — a Spanish word that can be defined as “straight ahead” — is an extremely powerful thunderstorm with straight-line winds generally between 58 and 100 mph.

The systems span more than 240 miles, and include hail and enough rain to cause flash floods.

Laymen call derechos land hurricanes. Victims call them scary.

Last June, a derecho packing winds of close to 100 mph barreled across the country from Illinois to the Mid-Atlantic, killing 13 people, causing $1 billion in damage and leaving more than 4 million people without power.

The current storm is so big that it could affect one in five Americans — about 64 million people in 10 states — as it rumbles from Iowa to Maryland packing hail, lightning and tree-toppling winds.

New Yorkers, still reeling from Hurricane Sandy last year, could dodge the heavy stuff, but they should still brace for a soggy day today with up to two inches of rain and coastal flooding.

“New York is on the fringes of the severe weather threat,” said Accu-weather meteorologist Tom Kines.

The risk of severe weather in Chicago, Indianapolis, Cincinnati and Columbus, Ohio, yesterday was roughly 45 times higher than on a normal June day, forecasters said.

And in the upcoming days, Detroit, Baltimore, Washington, Milwaukee, Pittsburgh and Louisville, Ky., have a risk level 15 times more than normal.