It’s been so warm so far this December, that this weekend’s high temperatures in the low 40s will feel shockingly cold even though our highs and lows will match the statistical averages for these dates.

For Saturday, gusty winds will make average temperatures for December feel even colder, despite sunny skies.  Highs around 42.

For Sunday, expect sunny skies and less wind with high temps around 43.

As mentioned a few days ago, the upcoming week before Christmas will be warm and wet with possible record-breaking warm temperatures X-mas eve.

In fact, the current pattern of mostly warm with shorter intervals of [near average] cold weather will likely be with us through the end of this calendar year.  

A warm and increasingly moist southwesterly to southerly flow of air around a slowly departing high pressure system will continue to provide possible record setting high temperatures for us this weekend.

For Saturday, moisture overnight will break for partly sunny skies.  An increase in moisture will bring cloudiness back in the late afternoon.  High 64.

On Sunday, a further increase in moisture will result in mid-level cloudiness and mostly cloudy skies, with possible brighter breaks. High possibly as high as 70, if we get some sunshine poking through.

It looks like the first taste of winter will arrive late Thursday with next weekend being quite cold.  However, the cold won’t last very long.

Update Sunday 12/13:

It took awhile for the altocumulus to roll in today. The rain will arrive earlier on Monday.  Next weekend will be very cold here, but temperatures will moderate after a few days. The long range forecast  for X-mas wet and mild.

The remainder of the month looks to be very active, with plenty of moisture and rain, alternating periods of cold and warm weather.

The large blocked high pressure system that has given us the unseasonably mild temperatures will move east allowing a frontal boundary to move through.

On Saturday, look for increasing cloudiness with showers by evening.  (The daytime hours should be dry. ) Mild temperatures continue with highs in the low 60s despite the cloudiness.

Update; This morning’s models have the rain today (Saturday) starting as early as 2-3 PM

The models diverge a bit for Sunday, with the GFS having showers ending early morning with just lingering cloudiness and cooler temperatures. The NAM model has the front stalling closer to PHL with showers continuing into early afternoon Sunday.  High 56.

There has been a lack of continuity with the current blocked upper air pattern, so this Sunday’s forecast is lower than usual confidence. I suspect the NAM’s handling of the frontal showers continuing into the day Sunday may be correct.

The latest NAM run is similar to the GFS model– rain ends early Sunday morning and skies clear in the afternoon.