Tornado Watch Issued Across Philly Region

Updated, Friday at 5:30 p.m.: A tornado watch has been issued across the Philadelphia region, including in Bucks, Montgomery, Delaware, Chester and Philadelphia counties. It is in place through 12 a.m. Saturday.

The National Weather Service warns incoming storms could bring some tornadoes, as well as the potential for "ping pong ball-sized" hail.

This development comes after forecasters had warned earlier Friday of potential severe storms.

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A low pressure system moving towards the Mid-Atlantic region could bring strong thunderstorms with heavy rain and gusty winds, the National Weather Service is predicting. The system is expected to move into the Philadelphia region by Friday evening.

Some thunderstorms could be strong to severe, possibly resulting in local areas of flash flooding, according to forecasters. The storms are most likely to hit between 4 and 10 p.m., the NWS said.

"From the Mid-Atlantic southward into the Southeast, lines of thunderstorms could contain severe weather as a cold front associated with the intensifying system sweeps across the region later today into tonight," according to the latest NWS forecast.

Damaging wind gusts are a primary threat during this storm, and residents should be mindful they could knock down trees or power lines.

A flood watch has been issued starting at 7 p.m. Friday and lasting through 8 a.m. Saturday. Rainfall amounts of up to 3 inches expected in the flood watch area, with rates of more than an inch per hour possible.

The stormy conditions will linger through Saturday, with the chance of precipitation set at 90 percent.

By Saturday night into Sunday morning, a cold front will bring temperatures further down across the Mid-Atlantic region, with lows dipping to the 50s in the Philadelphia region.

AccuWeather expects the wet conditions to linger off and on through the start of June. "Temperatures will trend upward in the East as June progresses, but there will still be more rounds of showers and thunderstorms as the busy pattern continues. Rain-free weather is not likely to last more than two or three days in a row," AccuWeather said in its latest forecast.

Here is the local forecast:

Today: A chance of showers, mainly after 5pm. Patchy fog before 10am. Otherwise, partly sunny, with a high near 80. Calm wind becoming west around 5 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers and thunderstorms before 5am, then showers likely. Low around 59. South wind around 5 mph becoming north after midnight. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 inches possible.

Saturday: Showers likely, then showers and possibly a thunderstorm after 11am. High near 72. West wind around 10 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.

Saturday Night: Showers and thunderstorms before 11pm, then a slight chance of showers between 11pm and 2am. Low around 50. West wind 5 to 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Sunday: Sunny, with a high near 70. West wind around 10 mph, with gusts as high as 20 mph.

Sunday Night: Partly cloudy, with a low around 51.

Monday: Sunny, with a high near 75.