The forecast from Friday remains on track. High temperature 57-59. Clouds move in during the afternoon.
Winds 5-10 mph W->WSW, increasing later in the afternoon::
HRRR forecast -Fort Washington gridpoint
Forecast Update Sat AM
Very windy, as expected, today. NBM model wind forecast for our area Saturday (in red box)
The deep low pressure system that brought us heavy rain Thursday into early Friday will move away while it deepens. A cyclonic flow of colder air will move in for Saturday.
Saturday will be mostly sunny, windy and somewhat chilly. High 48. The models don’t show any instability cloudiness, although I’m curious to see if any develops in the cyclonic flow.
Sunday will start sunny. A low pressure system approaching from the Midwest will bring some cloudiness in during the afternoon hours. High 56-58.
The low pressure system and another cold front moves through late Monday with rain. Temperatures drop later Monday night. While there was some thought that there might be some snowflakes mixing in as the precipitation ends, the models, including the FV3-GFS, don’t seem to support that scenario now.
Update Saturday morning. The short range models show signficantly less stratocumulus cloudiness than the NAM. I guess we’ll see.
Following a cold front Friday evening, high pressure will build in for Saturday and Sunday.
After today’s very warm temperatures, Saturday and Sunday will be much chillier. Winds and some clouds on Saturday will make the day feel even colder.
Saturday will start sunny, but cold air aloft will result in a considerable amount of instability stratocumulus cloudiness at times, especially late morning and early afternoon. It will be windy and gusty. High 46-48.
Sunday will be sunny with light winds. Temperatures will still be below average, with a high of 45.
Average high temps are about 54ºF for Philadelphia.
Saturday will be mostly sunny with a light winds before low pressure approaches during the evening hours. High 49.
As a low pressure system approaches from the west, clouds move in during the late afternoon. Rain starts between 10pm and midnight.
Sunday starts rainy, moderately heavy at times in the very early morning. Rain tapers and ends mid-morning. It’s uncertain whether clouds will fully break for sun in the afternoon. Mild. High 60. (GFS and NBM)
As was the case a few weeks ago, the NAM shows lower temps for Sunday and has the high only in the low to mid 50s on Sunday.
A weak cold front moves through early Sunday evening with widely scattered showers.
For Fri afternoon- snow flurries. QPF ranges from 0.00 to 0.02 inches water. Not sure why the roads are being brined out here. Temps expected well above freezing.
This morning’s models have speeded up the exit of the rain for Sunday. It now looks like the rain will be over mid-morning Sunday.
Here are the important trends: the well-advertised rain moves in later on Saturday night and departs a bit later on Sunday afternoon.
Following the clipper type disturbance that moves through Friday afternoon, high pressure builds in on Saturday.
Saturday starts sunny with a light winds before low pressure approaches.
As a low pressure system approaches from the west, high clouds move in early afternoon Saturday and slowly thicken during the late afternoon. Winds become easterly. Rain about midnight. High 47.
Sunday starts rainy, moderately heavy at times in the early morning. Rain tapers and ends about noon-2 PM. Mid-morning. Some clearing of clouds possible, some sun possible. Mild. High 61. (GFS and NBM)
As was the case a few weeks ago, the NAM shows lower temps and has the high only in the low to mid 50s. on Sunday.