Spotty snow moved across Pennsylvania as freezing rain broke out in Maryland and northern Virginia. Then, just in time for the morning commute, the precipitation became heavier. It was so slippery around the Philadelphia area that walking a few feet was an invitation to a nasty fall, and driving conditions deteriorated rapidly. Near Media, Pa., there was a 15-car pileup, and a photo of an overturned salt truck made the rounds on Twitter. Farther northeast, there were snow problems around New York City, Providence, R.I., and Boston.
Here's the morning video. As always, check back for updated videos on AccuWeather.com throughout the day, any day.
With a big high pressure area off the East coast and the nearest cold front in the Plains, there is time for mild air to replace the coldness all the way to Maine. The combination of melting snow and the coming rain will lead to street flooding and stream rises. The National Weather Service monitors the nation's rivers, and here is their outlook for the Middle Atlantic region from this morning.
In the I95 corridor, tomorrow will turn wetter and warmer. Sunday will turn dry and chillier, but no return of really chilly air is likely until midweek, and even then it will not rival the cold wave that swept through this week.
This pressure map shows the strong circulation around the storm that brought all the warm air northward... and which will force colder air eastward next.
Looking at next week, the GFS ensemble spaghetti plot of upper air winds shows how much agreement there is among members of the ensemble (same model running multiple times using slightly different starting assumptions). The maps are from next Tuesday, Nov. 25, and Thanksgiving Day, Nov. 27. There is good agreement on the first map, but a lot of spread two days later.
The location of lake-effect snow bands is tightly controlled by geography, topography and wind. From this pressure analysis, we see why the wind favored heavy snow staying south of the hardest hit Buffalo snow belts earlier today.
If this timing works out, there would be good travel weather for the Northeast Corridor on Wednesday while snow showers cross the Great Lakes and reach the northern and central Appalachians.
This map from one of my tweets yesterday (accuElliot) showed the wind direction most favorable for heavy lake-effect snow in and near Buffalo. Just a minute change in direction greatly affects the location of the heaviest snow, almost as if you were operating a fire hose. The snow is so deep (more than 4 feet in spots and deepening) that officials were considering the use of high lift equipment to extract vehicles.
It suggests rain in the I-95 corridor and snow from the mountains of West Virginia and Pennsylvania to southwestern Maine. Other models and ensemble versions will be examined this weekend as we narrow down the uncertainties associated with this fast-moving storm. Whatever the form of precipitation, you can count on another shot of cold air behind it. Lake-effect snow will be common as well.