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Forecast Update

Update Sat 03/25 @ 4:38 PM — The models have backed away from thunderstorms developing in the immediate PHL area. The area of development may be South Jersey, about 10 PM

Sunday looks suuny. A bit windy. Temps upper 50s to near 60.

Update Sat 03/25 @ 10:33 AM — There have been some changes in the forecast.

The rain will be moving in over the next hour or so. Rain ends about 5-6 PM. Total rainfall about 0.2-0.5 inches. A second batch of rain and thunderstorms about 9-11:30 PM

Here’s the current water vapor image. The first boxed area (1) is the area of upward motion bringing the rain in the next few hours. The second boxed area (2) may bring some thunderstorms between 9-11:30 PM, (maybe missing the immediate PHL area, maybe not.) Some model uncertainty in the placement of the second batch of rain/thunderstorms.

Update Fri 3/24 11:20 PM — Tonight’s models show breaks in the rain Saturday with total rainfall on the light side. The warm front gets further north and temperatures rise to upper 50s late afternoon.

Update Fri 03/24 @ 7:59 PM — Minor update to include the mention of thunderstorms mid-day with the rain. The latest models have very high levels of helicity and vertical shear, greater than that which spawned Thursday evening’s surprise thunderstorms . Nothing severe expected because CAPE values are expected to be low.

The cold front that moved through Friday night has stalled to our south and will try to return as a warm front later Friday night as a cold front moves in from the northwest later on Saturday.

It appears that the warm front won’t make it north of our area, as low pressure is expected to form near the Delmarva coast.

The warm front, the low pressure system and the cold front will result in periods of rain for much of Saturday. Thunderstorms appear possible Saturday evening, especially north and west of the city.

Winds

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Sunday Forecast Update

Update Sat 03/18 @ 9:50 PM —We had more sunshine and less high, thin cloudiness from the city and westward Saturday than forecast.

Sunday starts sunny. There’s still uncertainty with the cloud cover early afternoon. Today’s GFS, HRRR and RAP still maintain a period of considerable low cloudiness Sunday from about noon until about 4 PM. More cloudiness northwest of the city. The HREF has minimal clouds.

There’s little disagreement about the very cold and the windy conditions for Sunday.

The NBM shows the wide “spread” (uncertainty) in the cloudiness forecast—

Previously Posted Fri 5:22 PM —

A cold front will move through this evening (Friday). Some showers expected tonight about 10PM- midnight, with most of the activity just south of the city.

A second cold front will move through Saturday night and lingering upper air disturbance may affect us Sunday morning with clouds.

There’s uncertainty regarding the amount of cloud cover this weekend.

Average high temperature is 53-54º for the coming week.

Winds