Philly Weekend Weather Forecast

A southwesterly flow of mild air will continue through early Sunday.  For Saturday,  a bit of clouds early morning, then mostly sunny skies and temperatures in the mid 50s.  Beautiful for December in Philly.

A cold front will move through during the day on Sunday. Sunday will be cloudy with showers likely during the afternoon and evening.  Temperatures still mild with highs near 49.

A broad trough will bring colder temperatures for upcoming week.  As mentioned in an earlier post, the cold front moving through on Sunday will stall not all that far to our south.  Disturbances may develop along this boundary.  The GFS suggests some light precipitation early Tuesday, otherwise dry.

Weather Pattern Change

GFS Surface forecast for Tuesday
GFS Surface forecast for Tuesday

Over the past few weeks, the weather forecasts beyond 3 or 4 days have been anything but reliable. Perhaps you’ve noticed?

With much of the energy coming in from the Pacific ocean where measurements are sparse, the weather system developments over the US have been difficult to pin down.

We are now going to see a major change in the overall weather pattern, perhaps due to the next phase of the Madden-Julian Oscillation. Over the next week, an anomalously large area of high pressure will settle into the Southwest and Rocky mountain states bringing extremely cold temperatures to areas that last winter were very warm.

We will get colder, but the frontal boundary of this cold air will be not too far to our south.

The disturbances hitting the west coast from the Pacific are expected to be shunted to the south below this boundary.

The GFS currently keeps us cold and dry.

Here’s the rub– with this sort of scenario, it doesn’t take much for a disturbance to form along the stalled frontal boundary. So instead of just cold and dry weather (as currently predicted by the GFS) we could end up with icy or snowy storms. Stay tuned.

Phillly Weekend Weather Forecast

Current GFS forecast for X-mas eve
Current GFS forecast for X-mas eve

Stratocumulus clouds hung in today, and temperatures stayed slightly below predicted highs. Clouds are expected to clear for Sunday and temperatures should reach the average high of 41 for tomorrow, the first day of winter.

The well-advertised intense low pressure system is on track for Wednesday, Christmas Eve. The upper air low, originally predicted to linger, now appears to be more progressive and moves into Canada quicker. The long range suggests much colder weather moving in next weekend.

Phillly Winter Weather Oulook

The current mild pattern will slowly revert back to more average December temperatures over the next several days.

A storm that had been expected to form over the weekend will probably pass off to our south,

The models are advertising a big change around Christmas Eve, with deep amplification of the jet stream, colder temperatures and possibly the development of a major storm. Stay tuned.

Storm Forecasts & Other Things "up in the air".