Tornado watch, more heavy rain in Philly area today

File photo: Philadelphia commuters and their umbrellas during the morning commute along N. 16th at Market St. (Alejandro A. Alvarez / Staff Photographer)

A tornado watch has been issued for the Philadelphia area.

The watch covers Philadelphia surrounding counties in Pennsylvania and South Jersey. The watch also covers much of Delaware and Maryland, according to the National Weather Service.

The tornado watch comes after downpours today have snarled traffic, disrupted public transit, caused airport delays and halted practice rounds at the U.S. Open. The tornado and flood alerts are also just days after Tropical Storm Andrea brought record rainfall to the Philadelphia region.

Authorities say the tornado watch is in effect until 10 p.m. A watch means conditions are favorable for severe thunderstorms and tornadoes to develop.

In Pennsylvania, Adams, Chester, Delaware, Lancaster, Montgomery and York Counties are under the watch, as well as Philadelphia. New Jersey counties under the watch are Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and Salem.

See "Tornadoes that touched down near Philly."

After downpours this morning, the weather service says moderate to heavy rainfall for the afternoon and evening, and a flood watch is in effect until late tonight.

An inch or two of rain is expected to fall in most parts of the region, with higher amounts possible in some areas. Because river and stream levels are already high after Friday's showers, "there is a heightened potential for flooding," the flood watch says.

By 6 a.m., "very heavy" rain was falling in parts of Chester County, southeastern Berks County and the west-central part of Montgomery County, according to a weather service flash flood warning. 

Two inches of rain had already fallen in some parts of those counties.

Downpours moving across southeastern Pennsylvania and southern New Jersey slowed the morning commute, with rainfall rates of up to three inches per hour and some street flooding.

In the afternoon, Philadelphia International Airport said flights were seeing delays of more than two hours due to the weather.

SEPTA said Route 102 trolleys were terminating at the MacDade station due to high water levels, and shuttle buses were transporting riders between MacDade and Sharon Hill.

Earlier today, service on New Jersey Transit's River Line between Walter Rand Transportation Center and Entertainment Center was suspended for about an hour and a half during the morning rush due to flooding in Camden. SEPTA's Norristown High Speed Line temporarily shut down the Ardmore Avenue station, near the U.S. Open at the Merion Golf Club, also due to flooding.

The chances for showers will lessen around midnight, when a cold front moves through the area, the weather service says.

A high temperature of 77 degrees is forecasted for today.

Here's what to expect for the rest of the week:

A chance of showers and thunderstorms continues Tuesday, though the weather service says there's only a 50 percent chance of any precipitation. A high temperature of 85 degrees is expected.

There's also a small chance of showers on Wednesday and Thursday, with forecasted highs of 84 and 80 degrees. Friday should be mostly sunny, with a high near 79.

Contact Emily Babay at 215-854-2153 or Follow @emilybabay on Twitter.

Contact the Breaking News Desk at 215-854-2443; Follow @phillynews on Twitter.