Category Archives: Weather Outlook


Following a very long period of warmer temperatures for November, this weekend will be a transitional time to a broad drop in the jet stream over the eastern half of the US for next week.

Saturday will feature a slight drop in the position of the jet and we’ll have cooler temperatures than we’ve had in the past week. Fair skies will prevail.

Canadian (CMC) 540 thickness -red line – Saturday afternoon

On Sunday, the upper air flow relaxes and a return of moisture and milder temperatures is expected with a warm front. Showers expected early Sunday.

A cold front later Sunday afternoon will bring additional showers and precede a more pronounced drop jet, with much colder air for Monday.

The timing of these fronts may change by the weekend. Stay tuned.

CMC Forecast for Monday with 540 thickness line (red)


What’s interesting is an ongoing condition that I’m going to refer to as a relative “lack of very cold air” to our north. Of course, it’s still early November, but things just look a little bit warmer than usual to our north—

German ICON Model Temperature Forecast for Monday.

While we’ll get some chillier conditions next week, I don’t see a pronounced or extended period of cold weather for us right now.


Following a cold start on Monday, this week’s weather is forecast to be tranquil and increasingly mild. High pressure is expected to set up in the Atlantic and will provide a southwesterly flow of mild air and fair skies.

A weak disturbance will move through Tuesday and another Thursday night with just some cloudiness. Otherwise fair skies.

Temperatures are forecast to reach the mid to upper 60s by the end of the week. Even next weekend is currently expected to be mild and dry.

The next system that might affect us might be the remnants of the latest tropical–“Eta”. The same high pressure system that will provide our nice weather will also block the northern movement of Eta in the short run. However, that won’t be until next week.


Additional rain is expected Thursday night into Friday morning.  Clearing is expected between 2 and 4 PM Friday.

Friday night and early Saturday morning will feature cold temperatures— at or below freezing for much of the area.

NBM Minimum Temperatures by 8AM Saturday  (Click on image for a larger view.)

Brief outlook for the weekend—

Saturday will be sunny and relatively chilly.  High temps around 48º.

Halloween evening— clear and dry with temps around 40º

Sunday will be milder in the morning with significant cloudiness, but a cold front moves in during the late afternoon preceded and accompanied by some showers/rain.  High near 58, but temps fall again during the evening following a quick dip in the jet stream.

Incredibly, the extended GFS model has another tropical storm/Hurricane forecast in two weeks.



A complex weather scenario involving a strong upper air”closed low”, a surface low, and the remnants of Hurricane Zeta will affect our weather from Thursday into at least early Friday.

The complexity of this setup can’t be over-emphasized and it’s likely that no existing weather model can accurately forecast how this will finally come together. Despite the complexity, the models are in relatively good agreement right now.

GFS 7 PM Thursday forecast with 1 hour rain forecast.

It appears that the upper air low and the tropical remnants will remain separate, preventing explosive development like we had with tropical storm Isaias. However, things could change and that possibility will need to be watched.

The models currently show a heavy rain event, starting Thursday morning and lasting into very early Friday morning. The CMC and GFS models have total rainfall amounts in the 2.0″ to 3.5″ range for the Philadelphia area.

As early as last Friday, the German ICON model was ahead of our GFS the Canadian models in predicting Zeta’s formation. The ICON model did very well with Isais’s precip totals. Here’s the latest ICON model cumulative precipitation forecast for the storm—

Icon Model storm total cumulative rain forecast

I expect changes in the forecast. Stay tuned.