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.
Numerous tropical models show tropical storm Joaquin becoming a hurricane, possibly Category II, over the next day or so and many of those models suggest a track into the east coast, anywhere from the Carolinas to Delaware over the weekend.
In the past, my preferred model for hurricane paths was the Navy NOGAPS model, now called the NAVGEMS
The NAVGEMS has Joaquin hitting pretty far south, near South Carolina. Numerous experimental models show the path of Joaquin hitting the east coast further north.
The GFS model has the storm further intensifying at sea and hitting the east coast around Virginia over the weekend. Hurricanes are tough to forecast and their presence along the coast often affects the forecast accuracy of non-tropical systems in the regular daily forecasts.
This storm needs to be watched, since it beginning to appear that it will affect PHL in some way (heavy rain potential and winds) over the weekend.
