The National Weather Service has issued a flash flood warning for portions of the Washington area until 12:30 a.m. and flood watch for the rest of the region through Friday afternoon.

The areas under the warning are the District, Prince George's and Arlington counties and the city of Alexandria.

A flash flood warning means that flooding of streams and creeks is occurring or is imminent. A flood watch means that flooding is possible but not imminent.

The watch, which was broadcast for the entire area early this morning, preceded slow moving thunderstorms that began drenching the area mid-afternoon and were forecast to continue through the evening. They brought an inch to 1.5 inches of rain to the region, according to the weather service.

The flash flood warnings were issued as weather service forecasters noted that radar showed thunderstorms with very heavy rain in the area moving north. The weather service said one to two more inches of rain could be possible before 7:30 p.m. More rain was expected to set in after 8:30 p.m.

Overnight, the remnants of Tropical Storm Bonnie are expected to hit the region, bringing widespread heavy rain, the weather service said, with the ground already saturated from storms Wednesday and earlier today. The weather service said one to three inches of rain could be expected from that storm and some isolated areas could see as much as five inches. The precipitation is expected to end by noon Friday.

But forecasters have a wary eye on Hurricane Charley, which was predicted to hit Florida Friday and head up the East Coast with more flooding rains and strong winds later in the weekend.

Pepco officials were encouraging consumers to make sure they have emergency preparedness kits ready because the heavy rains and wind could bring down trees or tree limbs that knock out power lines.