Friday 11 a.m.
The storm that unleashed a blizzard in the central Plains has weakened as expected. The low pressure area will be moving over the upper Great Lakes tonight and tomorrow morning then will drift toward the St. Lawrence Valley. Dry air has punched eastward from Illinois through Ohio, and that will help limit how much precipitation there can be between Washington, D.C., and New York City later today and tonight. However, with temperatures not far from the freezing mark, it pays to be alert for slippery conditions tonight, especially in the northern and western suburbs of those cities.
Tomorrow and tomorrow night, a low pressure area will take shape off the Middle Atlantic coast. Rain is likely in the I95 corridor from this storm tomorrow. The remains of the northern storm may cause some snow from central and eastern New York state into parts of New England tomorrow, with light accumulations possible. As the coastal storm strengthens into a full-blown nor'easter on Sunday morning, a band of heavy snow seems likely from eastern Connecticut and Rhode Island through Massachusetts, New Hampshire and southern Maine. In the southeasternmost portion of that area, temperatures will be borderline between rain and snow... and the outcome will greatly affect how much snow can accumulate. Places that get all snow can get more than 8 inches.
Early next week, another storm will move northeast from the southern Plains. While a lot of mild air will be pulled northward ahead of the storm, strong cooling will be taking place aloft from west to east. This could mean accumulating snow all the way from Iowa and Illinois to the mountains of Pennsylvania. The storm may get blocked as it heads toward eastern Canada. If that happens, there can be a multi-day siege of wind and chilly for the Great Lakes and much of the Northeast, with snow showers downwind from the Great Lakes into the mountains. This kind of setup will cause many people to long for spring, but I know Sam the Dog will appreciate any snow that gives him the opportunity to go "snow-bathing."
On this map from 10 a.m. ET Thanksgiving Day, you can see the high pressure area that is causing dry and mild weather in the East and the cold front farther west.
During the late afternoon and early evening hours, the cold front of a knife will slice through the turkey and cause it to accumulate 1-2 inches on plates...
This satellite picture shows clouds over parts New York and Pennsylvania, as well as areas of low clouds, fog and snow cover from Michigan to Illinois. Most of the Northeast should have at least some sunshine through Thanksgiving Day.
As we go through the week, the flow aloft over the East will become southwesterly. This will promote a major warmup. This map shows the projected upper-air flow for Thanksgiving afternoon:
A major snowstorm will affect the area from Iowa to Michigan tonight and tomorrow. At first, snow can melt on streets, but as it continues and the temperature drops, the area impacted by slippery conditions will increase dramatically. This map shows expected accumulations:
This map shows two cold fronts in the northeast quarter of the nation; 9 a.m. ET temperature are plotted. The isobars are closest together over the central and western Great Lakes, and this is where the strongest winds were occurring.