Got plans? You best cancel them.

A Severe Thunderstorm Watch is in effect for New York, New Jersey and Connecticut through 9 p.m. Sunday. According to forecasters, look for thunderstorms mainly in the evening hours, conditions ripe for tornado activity --particularly in areas like Staten Island.

Add a flash flood watch to this, and the Tri-State is looking at a real mess. It will be in effect until late Sunday. .

That means certain thoroughfares, like parts of the FDR in Manhattan and the Saw Mill River and Bronx River parkways in Westchester may be impassible at some juncture. Low-lying areas in Brooklyn, including Sea Gate and Canarsie will be hard-hit. Also expect areas around the Hackensack, Passaic and Raritan rivers and parts of Wayne and Bound Brook, N.J. to be flooded out.

Expect substantial mass transit delays. According to the Metropolitan Transit Authority (MTA) there are 60 to 90 minute delays in both directions between Jamaica & Valley Stream affecting Babylon, Far Rockaway & Long Beach branches. Buses are also being provided between Jamaica & Valley Stream. Eastbound Long Beach service out of Penn is suspended. This is due to several trees down at Rosedale & Laurelton, & weather-related signal problems.

Meanwhile, things aren't a whole lot better at the airports. Due to WX / TSTMS and WEATHER / THUNDERSTORMS, there is a Traffic Management Program in effect for traffic arriving John F Kennedy International Airport, New York, NY (JFK). This is causing some arriving flights to be delayed an average of 1 hour and 16 minutes. Due to WEATHER / THUNDERSTORMS, departure traffic destined to Newark International Airport, Newark, NJ (EWR) is currently experiencing delays averaging 3 hours and 5 minutes. Due to WEATHER / THUNDERSTORMS, departure traffic destined to La Guardia Airport, New York, NY (LGA) is currently experiencing delays. Don't forget to call your air carrier before venturing out.

On the road, resist the urge to push through flooded areas around train trestles and the like; you WILL get stuck.