Tuesday 10 a.m.
A cold front approaching the East Coast separates mild, moist air to the east from colder, slightly drier air to the west. Buffalo's temperature passed the 60-degree mark Sunday and yesterday but will fail to get above freezing this Thursday.
A fast-moving clipper from the northwest may spread snow across the upper Great Lakes and perhaps into central and northern New England between late Friday and Saturday. As a warm front ahead of the low pressure area moves northward, it will be milder Friday In Chicago and perhaps in D.C. and Philadelphia on Saturday.
Cold air should return southward behind the low, but the cold front leading the way may stall before getting south of Virginia. A low pressure area could then form along the front to send snow or rain into the area between NYC and D.C. late Sunday into early Monday.
Then, a larger storm is likely to develop in the Plains. The Sunday night run of the European model showed that storm heading to the Middle Atlantic coast late Tuesday or Wednesday. I included a map of that on my video yesterday. However, last night's run took the storm toward the Great Lakes. That would mean a much warmer storm for the Middle Atlantic states and perhaps New England. Such a storm could bring substantial snow to the western and perhaps central Great Lakes regions while spawning thunderstorms in the warm air on its south side. Here is the video I made this morning:
The Pan-STARRS comet has recently become visible without binoculars or a telescope low in the sky around sunset. Tonight it will appear in the same neighborhood near the thin sliver of the recently new moon. However, with cloudiness likely to block the view for much of the northeast third of the country, what is a comet watcher to do? In an effort to cheer you up, I made an exclusive photograph called "Comet over a Coastline." I think you will agree it quite visible in this picture:
At midnight, the temperature will be in the 50s to low 60s from Virginia to Southern New England... more like late spring than Christmas time. Meanwhile, cold air will be advancing into western parts of Pennsylvania and New York, driven by strong winds. Earlier, this "cold" air mass looked like it would be more potent than it has turned out to be. This map shows the pressure pattern and some temperatures at 9 a.m.
Temperatures are likely to be in the 50s from Boston to Washington, D.C., during the nighttime hours of Christmas Eve. Dry chillier weather will arrive during Christmas Day, with dry weather lasting until at least Saturday.
This picture, which may or may not have been taken very recently, has a red dot near the North Pole. I cannot confirm that a red dot is there on the ground or that it means anything. We will monitor the area for any signs of activity and advise everyone to maintain the spirit of being nice and not naughty.
Rain with areas of fog should spread from Virginia to New Jersey Monday or Monday night then spread into New England for Tuesday. From the mountains of northeastern Pennsylvania into the interior of New England this could at least start as snow or ice. The GFS for 1 AM New Year's Day looks interesting. See the map below. Whether or not this storm develops and where it will snow or rain cannot be precisely predicted two weeks in advance using these models.
This map is a spaghetti plot showing the upper air currents predicted by members of last night's GFS ensembles. In looking at each line, you see variations, but they all show the idea of major trough centered east of the middle of the country on Christmas Eve.
Any storm in the Northeast could be disruptive for travel, whether it turns out to be rain and fog or snow and ice. If a strong storm develops, the best chance for snow on Wednesday will be over the central or northern Great Lakes region. This map is last night's GFS operational solution for 7 p.m. ET Christmas Eve.