CHICAGO (STMW) — Yet another severe summer thunderstorm has left nearly 18,000 Commonwealth Edison customers without power Thursday night — and more heavy rain is on the way.

ComEd has restored power to 145,000 customers affected by the Wednesday night storm, but about 17,900 are still without power as of 8 p.m., spokesman Paul Callighan said. That includes 6,200 in the western suburbs and 5,400 in Chicago. In the northern suburbs, 4,300 are without power and in the south suburbs, 1,900 customers were affected, he said.

More rain is on the way Thursday afternoon and night, and the National Weather Service has left its flash flood watch in effect until Friday morning. That includes portions of Illinois and northwest Indiana, including Cook, DuPage, Kane, Kendall and Lake counties in Illinois and Lake and Porter counties in Indiana, the weather service said.

That area will also have to deal with heat indices over 100 degrees, thunderstorms that can produce damaging winds up to 60 mph and very heavy rainfall that could lead to localized flash flooding, the weather service said. Wednesday night’s storms recorded 40 to 55 mph winds as of 11:45 p.m.

It’s more rain to areas that don’t really need any more and additional heavy rain could lead to rapid flooding, the weather service warns. Areas along and north of I-88 and I-290 appear to have the greatest threat for the heaviest rainfall through Thursday morning.

Areas to the south of the highways down to I-80 could also see heavy rainfall and flash flooding.

A flash flood means that conditions may develop that lead to flash flooding, which the weather service calls a “very dangerous situation.”

When will it be dry again? Storms will continue on Friday but the weekend will warm up with a sunny 87 degrees on Saturday.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2010. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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