Chester County Under Tropical Storm Warning

[Update 8/26/2011: The tropical storm watch for Chester County has been upgraded to a tropical storm warning.]

The National Weather Service has issued a hurricane watch for Philadelphia and Delaware counties, and a Tropical Storm watch is in effect for Chester, Montgomery and Bucks counties.

A watch means that the weather condition is expected, but not imminent.

The local weather forecast calls for a possibility of tropical storm conditions, starting Saturday night, with storms and the possibility of heavy rainfall. The conditions could last through Sunday.

Irene is still a Category 3 hurricane with maximum sustained winds of 115 mph, according to NWS. The core of the hurricane is expected to move north along the northwestern Bahamas Thursday night.

Irene is getting larger, and the storm watches in the Carolinas have been upgraded to warnings.

National Oceanic and Atmospheric Administration (NOAA) has issued a hurricane warning for the entire coast of North Carolina, from Little River Inlet on the South Carolina border north to the Virginia border. A hurricane warning means tropical-storm-force winds are expected somewhere within the warning area within 36 hours. In the warning area, NOAA forecasts a storm surge of up to 10 feet and life-threatening waves.

NOAA has issued a tropical storm warning for South Carolina from Edisto Beach north to Little River Inlet on the North Carolina border. A tropical storm warning means tropical storm conditions are expected somewhere within the warning area within 36 hours.

A hurricane watch has been issued for the East Coast from the NC/Virginia border north to Sandy Hook, NJ. That includes Chesapeake Bay south of Smith Point. In the hurricane watch area, NOAA forecasts Irene could produce "significant storm surge flooding" (no numbers were offered).

A tropical storm watch has been issued for Chesapeake Bay from Smith Point north, as well as the Tidal Potomac.

The storm is also getting larger. Hurricane-force winds now extend up to 90 miles from the center (Thursday morning it was 70 miles), and tropical-storm-force winds extend up to 290 miles from the center (Thursday morning it was 255 miles). NOAA is reporting that Irene is producing swells that will cause life-threatening surf and rip current conditions along portions of the East Coast. It did not specify which portions.