Once again the Delaware Valley, Mid-Atlantic, and Northeast, will experience another prolonged shot of very cold air, and possibly some Light snow and Flurries. A Strong Arctic front will be moving through the area later Thursday into Thursday night, and usher in another very cold air mass for Friday through early next week (Tuesday). The passage of this Arctic front could spark a few showers and snow showers (mainly N & W) for later Thursday afternoon and evening. I'm expecting High temperatures for Friday 12/5 through Monday 12/8 to remain in the mid to upper 30's and lows in the Upper teens to mid 20's. Normal temperatures during this period are in the mid to upper 40's for highs, and the low 30's for the lows. So I expect daily departures to be -5 to -10 during this 5 day period, this is below to much below the normal average.
On Tuesday we remain cold and below normal with temps in the Low 40's, and lows in the mid to upper 20's. As we head into next week, the uncertainty of the pattern increases somewhat. I will get into more detail about this over the weekend in another post. It appears we could be heading for Near normal temps, and some mixed precip to a chilly rain towards the middle of next week, as a complex storm approaches from the West and Southwest.
Now let's get into this weekend and talk about the threat for some light snow and snow showers. A large Trough moves into the East for Friday through Monday, along with a Shortwave, H5 Vort. energy, and an Alberta Clipper system approaching from the west on Saturday night into Sunday. At the same time a coastal storm is also expected to develop well offshore during this time, off the Northern M/A Coast, then move Northeastward. It's likely these two systems will remain separate and not phase into a bigger coastal storm or a big snow threat.
With this being said, I expect a period of light snow and snow showers to effect the entire Delaware Valley, from late Saturday night into Sunday. My preliminary estimates are for a general Coating to 1" of accumulation with this system.
If the H5 Vort. energy sets up in a more favorable position, and some Atlantic moisture is thrown in from the coastal storm, then a 1" to 3" event would be possible. For now I'm going with a Coating to 1" as my preliminary call. I'll do a complete update on this possible event sometime between Friday and Saturday AM. Things should become more clear over the next day or two with this system.