A potent late-winter storm will wallop New England with heavy snow on Wednesday and Thursday, but this storm looks to bring rain to the major cities of Philadelphia, Baltimore, and Washington. Computer forecast models are still in disagreement with the exact track of the center of low pressure; however, the general track should move along a line from Cincinnati OH to Pittsburgh PA to just to New York City to Boston. This track will keep all of the coastal plain from Washington to Boston in the warm sector of the storm. Consequently, all of the precipitation will fall in the form of rain (Boston may begin and end as snow.) There is a slight chance that Philadelphia, Baltimore, and Washington could see a change over to snow showers at the end of the storm when colder air wraps around the departing area of low pressure.
There main factors that will make this a rainstorm in the big cities as opposed to a mix or snow scenario includes the fact that there is a lack of fresh, cold air in place over the northeast, an absence of cold high pressure to the north, the storm will intensify too late, and the track of the storm is to the north of Philadelphia, Baltimore, and Washington.
Regardless of what happens with this storm, a fresh surge of cold air will jolt the northeast and Middle Atlantic states on Thursday with highs only in the upper 20s in Philadelphia, around 30 in Baltimore, and the lower 30s in Washington DC. Fortunately, the cold will be short-lived as is typical for this time of year. Most locations will be back in the 40s on Friday and 50s on Saturday.