Northeast on alert for rain and snow ahead of cold snap

Forecasters warn that the weather will be like night and day for millions of Americans living in the eastern United States from the start of the week to midweek.

Easterners woke up to a drenching rainstorm and a surge in unusually warm air to start the week. On Wednesday they woke to biting cold and even a covering of snow.

Soon after the rainstorm moved away, a much weaker storm developed along a trailing cold front. The very weak storm has had just enough influence to slow the departure of moisture.

Much colder air arrived on the back side of the system as it moved along to the east, causing rain to mix with and change to wet snow along an approximate 1,000-mile corridor from northern Mississippi to southeastern Maine spanning Tuesday night to Wednesday morning.

While the majority of roads in this area will be just wet, slushy accumulation has occurred on grassy areas, vehicles and elevated surfaces in the Interstate-95 corridor. This has occurred even though temperatures less than 24 hours earlier were in the 40s, 50s and even the 60s F.

A period of snow fell over interior cities such as Knoxville, Tennessee; Charleston, West Virginia; Winchester, Virginia; Hagerstown, Maryland; Reading, Pennsylvania; Morristown, New Jersey; West Point, New York; Hartford, Connecticut; Worcester, Massachusetts; and Keen, New Hampshire.

As of early Wednesday morning, snow fall totals of 1 to 3 inches occurred reported in the Appalachian Mountains of Kentucky, Tennessee and West Virginia.

In southeastern New England, a more general snowfall occurred from Connecticut to northeastern Massachusetts at the start of the day on Wednesday. Accumulations ranged from 1 inch to 6 inches as of 8 a.m. EST Wednesday.

Along the I-95 corridor, the Wednesday morning commute will to be dramatically different, when compared to the drive home from Tuesday. Snow may fall at a fast enough pace in some areas to create slick roads, especially in the suburbs from Washington, D.C., and Baltimore to Philadelphia to New York City.

A more general snowall has occurred in southeastern New England, including the Boston and Providence, Rhode Island, metro areas. AccuWeather meteorologists warn that weather conditions can be adverse enough to cause significant travel delays.

Exactly how much snow is able to accumulate on roads is dependent on how quickly these surfaces cool and the intensity of snowfall.

Most road surfaces had a chance to warm up during Monday and Tuesday, due to the surge of warmer air. The roads retained some warmth for a time even as the colder air and snow arrived late Tuesday night and Wednesday.

Initially, some of the snow melted on warmer surfaces. But, elevated surfaces such as cars, lawns, decks, porches, bridges and overpasses are likely to become snow-covered much faster than city streets and main highways. Where snow falls for several hours at a fast pace, roads will become slippery and shoveling and plowing operations may be needed.

Experts urge motorists, pedestrians and road crews to be prepared for a quick freeze-up that advances eastward through Wednesday.

Arctic air is forecast to slash temperatures by 15-40 degrees Fahrenheit in about 24 hours. After the balmy start to Tuesday, millions will be in for a cold shock and a bit of a reality check by Wednesday.

Aside from lake-effect snow that ramps ups with the arrival of Arctic air, no significant wintry precipitation is forecast from northern New England to much of the Ohio Valley with this storm as dry air will race in.

Download the free AccuWeather app to check the forecast in your area. Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.