Monday 9:45 AM
A storm crossing the Gulf states dropped heavy rain over a wide area, and the moisture is moving northeastward. However, the upper air trough supporting the rain is shown to weaken slowly on the computer model (I use this term interchangeably with numerical forecasts) maps, and so places in the Northeast should not match the Gulf states in the rainfall amount department. One thing that is apparent is with a persistent flow from the Gulf states to New England, it will be warmer than average for this time of year.
Last week at this time, I showed a GFS forecast map for Oct. 10 that suggested it could snow in central and northern Pennsylvania. I suggested the model would change looks over time and, in fact, the very next run has a warmer look and no snow. On the other hand, a typhoon re-curved over the western Pacific, and this kind of event has often been followed by an upper air trough n the East about 10 days later. The most recent runs of GFS has trended toward this trough in the East scenario, and this suggests next week will be quite a bit cooler than this week (with the first push of cooler air arriving this weekend).
The numerical forecasts (I use this term interchangeably with computer models) for next week will certainly change in various ways before next week arrives, but there are hints that the higher terrain downwind from the Great Lakes could get their first snow showers of the season next week. This map for next Thursday shows a close call setup for this:
Meanwhile, my daily video shows what we can expect this week:
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.
The map below shows the low pressure area and cold front now moving into the East. Looking at the temperatures, truly cold air is well behind the cold front. This is in line with the idea that the front itself is the leading edge of the change to colder conditions.
The following map shows why areas to be affected by the cold front will not have a long period of rain. However, along and north of the storm center, the precipitation will last longer.
The satellite picture shows a deck of clouds all the way along I-80 from Nebraska to New Jersey with few holes along the way. However, nobody in the cloud zone is having any substantial precipitation. There was some spotty freezing drizzle this morning.