Weather forecast: Severe thunderstorms, tornado possible tonight

This story originally appeared on 6abc.

Meteorologists are tracking the threat for severe thunderstorms this evening, then much cooler temperatures come Sunday.

A tornado watch is in effect for Philadelphia and the entire viewing area until 10 p.m.

A Tornado WARNING is in effect for Chester County, Pennsylvania and in New Castle County, Delaware. A warning is used when a tornado has been either spotted or picked up on radar.

A tornado watch is issued when conditions are favorable for a tornado. The areas under a tornado watch include:

PENNSYLVANIA: Bucks; Chester; Delaware; Montgomery; Philadelphia

NEW JERSEY: Atlantic; Burlington; Camden; Cape May; Cumberland; Gloucester; Hunterdon; Mercer; Middlesex; Monmouth; Morris; Ocean; Salem; Somerset; Sussex; Warren

DELAWARE: Kent; New Castle; Sussex

Tonight: Ahead of a cold front, we’re watching for the threat of strong thunderstorms this evening. These storms have had a history of producing 60mph+ wind gusts across Western PA today. Thunderstorms could become severe with our greatest risk being damaging wind gusts. We also can’t rule out an isolated tornado or two, so make sure you are staying weather aware. Behind the cold front the winds shift and it’s much cooler, low 40.

Sunday: Plenty of sun, but it’s much cooler, high 54. The northwest breeze during the day will make it feel like it’s only in the 40s.

Monday: Turning warmer under partly sunny skies, high 69.

Tuesday: Mostly cloudy and warm with a passing shower during the afternoon, high 75.

Wednesday: Mostly cloudy and warm with a shower in spots, high 72.

Thursday: A few spotty showers early, otherwise it’s mostly cloudy, breezy and warm, high 73.

Friday: Breezy and cooler under intervals of clouds and sun, high 59.

Saturday: Partly sunny and cool, high 55.