Not unexpected, models often don’t pick up upper air disturbances in the upper flow
Philly Weekend Weather Forecast
A dip in the jet stream will allow cold air to move in behind a front moving through tonight.
Saturday will be mostly sunny, cool and breezy. High 56. A weak upper air disturbance will bring in some clouds before sunset.
For Sunday, skies will be mostly sunny but another upper air disturbance will bring cloudiness mid to late afternoon. Less breezy. High only 52.
Philly Weekend Weather Early Outlook
The first significant dip in the jet stream for this fall/winter season will occur this weekend for the northeastern US. A cyclonic flow of cool/colder air will bring temperatures down to about 40 or less at night and the 50s during the day.
While the predicted upper air jet pattern has been consistent, the models have shown great variation with the possibility of upper air disturbances embedded in the flow. What this means is that it’s not a certainty how much sunshine we’ll get with these cooler temperatures.
Periods of sun and cloudiness looks to be the best bet, and there’s a slight chance of a quick sprinkle during the afternoon on Saturday and even moreso later Sunday afternoon and evening, as the upper flow changes to the southwest. A brief snow flurry Sunday night isn’t out of the question.
I’ll update Friday evening.