As a wave of low pressure moves through the east, it will lead to the development of rain showers across portions of the East this afternoon. It’s not until the overnight hours when colder air will allow for some of this rain to changeover to snow.
This afternoon, rain showers are forecast from southern New England through interior portions of the Northeast, much of the Ohio Valley, Tennessee Valley, and down into parts of the Southeast. By the evening, colder air behind the cold front will begin to intrude. That cold air will aid in the development of snow from Upstate New York through western Pennsylvania, down the Appalachian Mountain chain, and into the Ohio Valley. A few hours of snow is possible for cities like Lexington, Kentucky and Nashville, Tennessee.
During the night Thursday into early Friday morning, a line of showers will move through parts of the Southeast. Meanwhile to the north, snow will be falling from the Canadian border in Maine to as far south as potentially extreme-northern Georgia for a very brief period. The heaviest snow will be associated with the best moisture and lift, and that will be in the Appalachian Mountains from West Virginia through eastern Kentucky and Tennessee. From coastal Maine through the Washington, D.C. area, including the entire I-95 corridor, rain will likely changeover to snow during the early morning hours. This is the region that we’re most concerned about. Not only will it snow for a few hours, adding up to between a coating and two inches in this region, but freezing temperatures will quickly invade behind this cold front while the snow is still falling. Therefore, there is the potential for a flash freeze where all of the rain that fell will freeze on all surfaces. To the left, you can see the animation of the freezing temperatures rapidly moving toward the East Coast.
The combination of snow and this likely flash freeze will make for a treacherous morning commute in and near the I-95 corridor from coastal Maine through the Washington, D.C. region. Thankfully, the snow will give way to sunshine during the day but temperatures across most locations in the Northeast will remain in the 20’s, keeping most of the snow and ice around. Lastly, I also want to note that some lake-effect snow is possible in the Rochester and Syracuse areas coming off from Lake Ontario during the day Friday. Up to four inches of snow may fall in that area.
Here is our snowfall forecast. Drier air and lower moisture values will keep snowfall totals a smidge lower than surrounding areas in the Hudson and Connecticut River Valleys. Also note that our snowfall forecast does not represent the lake-effect snow expected behind this system.