Monday 8 a.m.
With a high pressure area off the East coast, the clockwise flow around the high means south winds and warmer air for the Middle and North Atlantic states today. However, a cold front will approach tomorrow, and after that the flow will be coming from middle of Canada. This video outlines the forecast ideas from today through the end of the week.
Temperatures are well below freezing in central Canada now, and the coming flow pattern will send the chill to the Middle and North Atlantic states. This computer model (U.S. GFS) map is for 2 a.m. EDT Wednesday.
This map shows a projection from last night's European model. It shows an huge temperature difference in a short distance across northern and central New England.
A number of you have submitted weather photos and graphics that we really enjoy. One person with a keen eye for how to visualize weather and climate events is Ralph Fato of Connecticut, who graciously allowed me to use this graphic about snowfall.
Snowfall amounts yesterday were low from Philadelphia to New York City. Accumulations increased toward the north and northeast.
This map shows the NAM's projection for this Friday night. The isobaric pattern suggests there is a southwesterly flow of mild air from the Gulf states to the Middle Atlantic region. Farther north, we see evidence of the frontal boundary that separates the mild air from chillier air.
A new area of snow now over southern Minnesota should expand southeastward to reach Chicago this afternoon, streak to Pittsburgh this evening, then reach the Philadelphia/New York City area late tonight or early tomorrow morning. This map shows a low pressure area over Missouri.
This map shows expected accumulations.