The first amplification of the jet stream this season occurs the end of this week, with high pressure diving down into the central part of the US.
Along the frontal boundary that will be right off of the coast, a low pressure system is expected to develop and move up, somewhat off the coastline. At this time, it might affect NJ and southeastern PA with light snow Friday night. Of course, if the upper trough sharpens and deepens, more of our area will be affected. If the trough becomes broader, we’ll miss the snow.
The statistical models now show something possible, but precip will be light and low probability.
This scenario has been suggested by the long range models for several days; the latest GFS run suggests greater intensification allowing light snow to reach westward into NJ and SE PA.
Stay tuned. (The models didn’t get the cloud cover correct for today; not sure we can trust them with 5 days in the future.)
An area of vorticity (an eddy current in the mid level of the atmosphere) is moving through today, giving us unexpected mid level cloudiness. We get these often in November and early December, but I’m not sure why the models didn’t show this on Friday.
This vorticity accompanies a change to a southerly flow in the upper atmosphere. Warmer temperatures expected through early Wednesday until a front moves through, bringing us much colder and winter-like conditions for Thursday through next weekend.
A large sprawling high pressure system will control our weather this weekend giving us dry conditions.
Saturday will start cold, but temperatures warm to the the low 50s. It will be sunny, but periods of mid level clouds will develop mid day as upper winds shift from the south. Some additional cloudiness late afternoon. Winds will be light and variable.
Sunday will be mostly sunny and a bit milder. High mid 50s. Breezy in the afternoon.
A pattern change is in store for the end of next week where a deep upper trough will bring much colder, windy and unsettled conditions. It will be winter-like.
