Hurricane Michael made landfall as the 4th strongest tropical cyclone to ever make landfall on the US mainland in recorded history. According to the National Hurricane Center, Michael made contact with land near Mexico Beach, Florida with maximum sustained winds of 155 mph (just shy of a Category 5 storm) and a minimum central pressure of 919 mb (the 3rd lowest pressure for a hurricane making landfall in US).
After causing catastrophic damage near the landfall zone, Michael remains on the move, now as a tropical storm over the Carolinas. Gusty winds and flash flooding are the main risks, although an onshore flow along parts of the Carolinas and Mid-Atlantic coasts may produce some coastal flooding in the form of storm surge through late-week. A Storm Surge Watch is in effect from Ocracoke Inlet to Duck, North Carolina.
Michael is now interacting with a cold front and a large trough of low pressure as it tracks east. This helps the storm move quickly. But unlike Hurricanes Florence (2018) and Harvey (2017), there are actually steering currents that will help this storm move and prevent absolute widespread flooding. Even so, the flash flood risk will be present for many. The Weather Prediction Center has a High Risk for excessive rainfall in place for western portions of North Carolina and southern portions of Virginia. Rain, some of which will be extremely heavy, is forecast across the Carolinas and much of Virginia this Thursday. By the end of the day, that rain will make its way into parts of the Mid-Atlantic, mainly near the Mason-Dixon Line. Numerous, spin-up tornadoes will be a risk associated with this rain, especially near the East Coast.
Meanwhile to the north, there will be a wide, multi-hour round of rain that will track east ahead of the cold front through the Northeast this Thursday. We aren’t concerned about severe weather, but since this front will be interacting with the deep, tropical moisture from Michael, localized flash flooding will be possible. This rain will push through by the evening, making room for Tropical Storm Michael to follow.
Michael will become centered over the DelMarVa early tonight, passing just south of Cape Cod Friday morning. The outer bands of rain are still expected to impact southern New England, Long Island, and New Jersey’s coasts despite the core tracking offshore.
Through Friday night, localized areas of the Mid-Atlantic can expect over half a foot of rainfall. Otherwise, a widespread 1-4 inches of rain seems to be the most common and likely amount of rain many along the East Coast can expect.