The Middle and North Atlantic states will emerge from the depths of harsh cold tomorrow, and weekend high temperatures can easily reach 40 or higher (50s in D.C.). A storm that brings several inches of snow to Chicago on Saturday will likely follow a path that takes most of the snow north of I-90 in the Northeast. This video show things should progress.
Looking ahead to next week, it appears a large storm will move from the southern Plains to New England at midweek, with heavy snow north and west of the track and rain elsewhere... maybe even thunderstorms in the Southeast. This snapshot map is from the GFS model for next Tuesday night. Since that is still almost a week away, future adjustments are virtually certain.
In other words, while late summers in Phoenix have gotten wetter during the last few years, Boston has become drier. Is there anything more momentous or general that we can say about this?
This enhanced infrared satellite picture shows the cold front in the Northeast and the moisture wrapping around Odille on the southwest part of the map.
Across the Central and Northern states, thunderstorms are less common at this time of year than in late spring and summer. One area that has had more thunderstorms than usual recently is across the Desert Southwest.
Last week, I mentioned that longer range computer models were suggesting a major warmup by next weekend. More recent runs have backed off on the that idea. However, there is extreme uncertainty beyond the next 7-10 days. This can be seen by looking at the following map.
n the forecast office, we often track cold fronts with pressure maps like these. The examples are from 4AM and 10 AM today. You can see that the northern part of the front is moving more quickly than the southern end. The arrival of the front signals the start of the cooling trend that is spreading east.
The upper air flow over the East is from the west-southwest now, and some of the moisture associated with the cold front can be traced back to tropical storm activity off the Mexican west coast last week. The same moist air mass set the stage for recent flash floods in Arizona. By early next week, the upper-air flow will be coming to the Northeast region from well up in western Canada, as seen on this forecast map forecast map for next Tuesday: