Thursday 9 a.m.
A cold front will shift from the Lake Superior area southeastward to reach the Middle Atlantic coast by midday tomorrow. There are several bands and clusters of thunderstorms ahead of the front, but sunny and less humid air follows its passage.
Video for Great Lakes and Northeast:
When we have thunderstorms in the forecast, we are often asked whether any of them are severe. When we answer, we usually think of severe thunderstorms with winds exceeding 58 mph, and perhaps we think about large hail. However, it doesn't take anything that strong to have serious effects. A 20- to 30-mph wind gust can shake branches loose, and heavy rain can cause street flooding almost immediately. And, if a lightning strike hits where you, who cares how "severe" the storm was! The following pictures include a radar image showing thunderstorms not far from New York City and a lightning plot covering the period from 5 a.m. until just after 9 a.m. EDT. Pockets of heavy rain and active lightning were the two major hazards associated with these storms. This is the kind of situation where thunderstorms can align with the upper air steering winds and so it keeps pouring right underneath the train of storms. This setup is dangerous and life-threatening.
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.