Philly Winter Weather Update

The models have been incredibly consistent with the forecast of precipitation moving in before daybreak on Saturday.

Update:  Light snow moves in after 1AM Saturday.

Expect some light snow before daybreak Saturday morning, but temperatures in the upper atmosphere warm up rapidly and changeover to sleet and freezing rain should occur in the early morning.

The big questionmark is how fast surface temperatures warm up.  The models always forecast too fast a warmup at the surface, so it is possible that much of Saturday morning will have a prolonged period of freezing rain and icy conditions, especially north and west of the city.

A more accurate handle on the vertical temperature profile for Saturday morning won’t be available until Friday evening.   Stay tuned.

Philly Winter Weather Outlook

Early Saturday Parallel GFS Model Forecast

The next arctic outbreak will reach us on Wednesday and will remain with us through Friday.

The active pattern continues and an impulse coming in from the Pacific will intensify into an intense low pressure system in the middle of the country.

As mentioned in my followup comments yesterday, we’re in a pattern where precipitation that moves in will be accompanied by a warm up.  For the rest of the month, the models are depicting us in the warm sector of storms that move up to our west.

The warmup is expected on Saturday, but with such prior frigid weather in place, the change to rain will likely be delayed with a prolonged period of freezing rain.

Right now, it looks like we’ll wake up to some snow Saturday morning, but it will change to freezing rain in the morning.  A prolonged period of freezing rain may be a possibility during the day on Saturday.

It should be said that this potential winter weather storm is a recent development in the models.  Much can change in the upcoming days, so don’t hang your hat on this forecast; expect changes.

Philly Winter Weather Update

Tonight’s latest short range models (NAM HRRR amd GFS LAMPS) show the possibility of light snow showers late morning and early afternoon Sunday in PHL before the main slug of moisture arrives as rain Sunday evening.

Any snow should be light; maybe a coating at most.

(It should be noted that the major models hold off the precipitation for PHL until early evening and show nothing during the day.)

Sunday Evening Update: Just a few snow flurries this morning, but no light snow. Radar looked impressive, but it was all virga, never reaching the ground.  So the major models prevailed here.  No more snow in the forecast right now.  The general trend seems to be cold and dry; when it gets wet, it also gets warm, as will be the case tomorrow.

The long term doesn’t show any snow for us and a white Christmas isn’t looking likely right now with a significant warmup possible around third week in December.