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.
This map shows how large an area is directly affected by precipitation on Tuesday morning. The low pressure center was in Kansas early today but will move all the way to Hudson Bay by Thursday while sending a cold front eastward on its south side.
A storm now moving through the Rockies will tap moisture from the Gulf of Mexico to threaten the central state with flooding rain. This map shows the GFS-predicted rainfall for the period from today through midday Friday.
The flow on Friday morning was strong but mainly from the west. This map shows that with west winds, it would not get very cold in the Philadelphia to Boston corridor.
In the strongest wind zone (where the lines are closest together), the winds have gusted past 50 mph. Peak winds with this storm will weaken slowly as the storm moves into eastern Canada by Saturday.
Milder air will spread across the Plains this weekend, and afternoon temperatures could easily reach the 60s in the Middle and North Atlantic states in the early to middle parts of next week. This map shows the predicted upper air flow for next Tuesday.
Analysis of isobars (lines of equal barometric pressure) can show where it will be windy because the lines are closest together. This computer model forecasts shows why it should be windy around Chicago on Thursday morning.