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Friday Forecast

Update Fri 03/03 @ 3:32 PM — Like earlier this week, evaporative cooling at the onset of the rain has resulted in a mix of rain and wet snow this afternoon. (Temperatures are in the low 40s) I went back to look at this morning’s models. The GFS and HIRESW-FV3 showed this possibility. The NAM and HRRR did not.

Update Fri 3/03 8:42 AM — The trend continues for a later start of the rain. Now, most likely 3-4 PM, but earlier far southwest of the city. Rainfall during the afternoon hours will be very light, only about 0.03”. Heavier rain starts about 9 -10 PM.

Update Thu 03/02 @ 5:25 PM — The trend for the large rain storm that will affect us Friday has been for the rain to start later in the day. This trend has continued with this afternoon’s models.

Current forecast: Rain moves in between 1 and 3 PM, earlier in the far southwestern suburbs of Philadelphia. It will become quite WINDY, especially towards midnight Friday.

By Saturday morning, about 0.75″ to 1.3″ of rain is expected in our immediate area—

Today’s NAM-NEST Total rainfall by 11 AM Saturday. Model precipitation forecasts should never be taken literally regarding placement of the heaviest rain bands. (Click on image for a larger view.)

Skies remain cloudy and unsettled on Saturday with lingering rain sprinkles and snow showers far north. It will be windy.

Thursday Update

Update Thu 03/02 @ 8:57 AM — As we saw yesterday, cloud cover is one of the toughest weather parameters to forecast correctly. Today may be no exception.

Most models have clouds lifting to significant high-level cloudiness with sun filtering through by noon Thursday. But the GFS has some stubborn mid-level cloudiness lingering into mid afternoon.

As for the rain on Friday, the trend has been for a later onset, probably closer to 1-2 PM. The rain moves in from the south. The rainfall later Friday and Friday night will be heavy at times. About 1-1.5″ of rain expected.

As mentioned in last night’s update, Saturday looks to be very cloudy with light widely scattered sprinkles and even some snow flurries (northern sections) possible.

Update Wed 03/01 @ 8:09 PM — A fast moving system will bring light showers just before daybreak Thursday. Showers move off to the east by 8 AM and clouds break for sunshine through a high cloud layer by about 11 AM from west to east.

The larger storm to affect our weather on Friday looks like it will move in later in the morning. around noontime. The chances of any sleet or frozen precipitation at the start looks to be low. A rain event for our immediate area.

Rain Friday afternoon and night.

Saturday looks very cloudy with low pressure lingering. Even a chance of widely scattered snow flurries or sprinkles.

Wed 8:16 PM Forecast Review — We had significantly more cloudiness today than forecast.

Wednesday Through Friday

Previously Posted Tue 8:15 PM —

Low pressure system that lingered (as forecast) today will move off to the east. Wednesday will be mostly sunny. Highs 52º-53º. Winds increase somewhat in the afternoon.

GEFS forecast for Wednesday at 1 PM Low pressure (1) links up with a stronger low in the Great Lakes to develop into a coastal low (2) near New England on Thursday. (Click on image for a larger view.)

For Thursday, low pressure approaches from the west, but the models have it transferring its energy to a secondary low off the New England coast.

We start out cloudy on Thursday with some showers mostly western suburbs. Then partly cloudy/partly sunny. Mild. High near 60º.

On Friday, a strong storm (similar to Monday night’s storm) approaches and takes a western track. We’ll be in the warm sector, but precip may start out as sleet/snow mix in the early morning. Rain for much of the day.

GEFS forecast for Friday 1 PM. (Click on image for a larger view.)