Strengthening storm to kick off a pattern change in the Northeast on Friday

1. The following surface pressure map doesn't look too threatening. There's a southwesterly flow of mild air in the East and a not-too-strong cold front west of the Great Lakes.

2. However, a storm now over Missouri will strengthen rapidly as it approaches the East Coast and will cause gale-driven rain from New Jersey to Maine on Friday. The rain will fall heavily enough to cause local flooding. Along east-facing shorelines, the combination of high winds and the added range of the tides around the full moon will raise the risk of coastal flooding. Then, as the storm goes by, enough cold air cold move in the change the rain to snow. This map shows a preliminary estimate of what could happen. More details on this tomorrow.

East of Detroit, this snow should not be a factor until tomorrow night.