All of the ingredients are coming together for a nasty weather event in the Mid-Atlantic region from DC-to-Philly-to-NYC later tomorrow and tomorrow night. A strong surface cold front is barreling eastward from the Upper Midwest and it is supported by amplifying upper-level support, and all of this will run into moisture-rich air advancing northward from the Gulf of Mexico. By later tomorrow, there will be an intensifying primary low pressure system over the eastern Great Lakes with a trailing cold front sweeping towards the east coast. A north-to-south squall line is likely to form just ahead of the front during the day Tuesday and this will head towards the east coast by tomorrow night. The bottom line is that there will likely be widespread showers and thunderstorms for the Mid-Atlantic tomorrow afternoon and evening that will include occasional heavy rain, strong winds of up to 50 mph, and even isolated tornadoes. Cool, dry weather will follow the frontal passage for the remainder of the work week beginning later Wednesday.