A cold front advancing through the Great Lakes and Ohio Valley today and tonight should move off the East Coast early Sunday. Showers and thunderstorms along and ahead of the front can be heavy with gusty winds, then cooler and drier air will move in behind it. This video shows the sequence of events.
This pressure analysis shows the frontal system that is causing showers and thunderstorms.
Fall starts officially at 4:44 p.m. EDT on Sunday. But I am calling fall's start a false start (as in football, where the offense loses 5 yards and has to start the play over again) because it will actually become warmer later next week.
This map shows the circulation around the offshore storm and a larger but less intense storm moving into the Great Lakes. With this sprawling storm likely to be in the region for several days, the weather can vary widely.
...speculation about a snowstorm Monday or Tuesday, and one is still possible. However, timing and placement remain elusive. This map shows the GFS ensemble mean "solution" for Tuesday morning showing snow just off the New England coast. Watch this story evolve on accuweather.com all weekend.
As we look father out this month, it looks cold for the Great Lakes and Northeast (as well as deep into the South) in the middle of next week but milder the following week. This map, for next Wednesday, shows a cold flow from way north in Canada.
A few tornadoes can also occur, especially from Mississippi and Alabama to Kentucky. This map shows the areas of potential severe weather through tonight as forecast by the NWS Storm Prediction Center.
A less prominent but strengthening band of snow showers was moving southeast across Wisconsin. That feature is the one that would cause snow showers tomorrow morning in the Northeast Corridor.