In our part of the world, cold frontal systems generally move in from the west passing through places like Chicago and Pittsburgh before they arrive here in the Mid-Atlantic. However, there are situations; especially, during the late winter and early spring, in which a cold front can slide down the Northeast US coast moving in a southwesterly direction. These types of fronts are commonly referred to as “backdoor” cold fronts as they “sneak” in from the northeast as opposed to the usual “front-door” type cold fronts that move in from the west. This time of year a “backdoor” cold front can make a huge difference in temperatures - suddenly replacing a warm air mass with a chilly, damp flow of air. These fronts are characterized by a high pressure system to the north that can result in a wind shift to an easterly or northeasterly direction which around here is right off the ocean and the latest sea surface temperature reading near Atlantic City is only 45 degrees. There is a good chance that a backdoor cold front will “sneak” down the coast over the next 24 hours or so and this would temporarily end the current warm weather - first in New York City and then in Philly. The DC region may luck out and remain in the warm air mass, but that will have to be monitored over the next day or so. Boston saw highs yesterday in the low 70’s and they are now sitting at 44 degrees with an east wind. I believe that temperatures tomorrow afternoon in New York City will be confined to the mid 50’s with an east wind, and then Philly may cool to the upper 50’s on Friday with an east wind, but maybe even chill down as early as tomorrow afternoon. The good news is that those places that actually do drop significantly in temperatures due to the passage of a “backdoor” cold front will warm up significantly again early next week as winds shift back to a southwesterly direction.