Thursday 9 a.m.
The morning weather map featured a low pressure area centered north of Lake Superior with a cold front extending south through western Michigan and then southwest past Memphis, Tenn. In the southerly flow of moist air ahead of this system, there is a large area of rain. It was cold enough for ice when rain began in the middle of Pennsylvania (and we even saw some snow outside of AccuWeather's headquarters), but most of the snow from this system will be confined to the mountains from the Adirondacks through the Green and White Mountains and on over to northern Maine.
As this storm heads out to sea, dry air that is still milder than average will promote fine weather in most of the Middle Atlantic states and New England tomorrow and Saturday. For Sunday, a storm variously depicted by the models could bring substantial snow and rain. It has been a week of flip-flops by the models. The problem is a changing assessment of how the upper-air currents supporting the storm interact with another branch of the upper-air flow crossing southern Canada and the northern U.S. In the meantime, this picture shows what kind of afternoon it will be from Washington, D.C., to New York City. I took the picture when my wife and I were visiting our younger son and his wife in Taiwan two years ago.
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.
Check AccuWeather.com's latest info as the forecast ideas mature. This is a draft of the Thursday morning snow accumulation idea.