A blocked pattern has kept a deep ocean low pressure system affecting our weather to our east for several days. The same blocking  has kept an even more robust low pressure system in the upper Midwest.

The ocean low pressure system will gradually progress eastward, allowing much of Saturday to have considerable sunshine before clouds move in again later in the afternoon.  High 68.

The second system in the Midwest will slowly progress eastward and an upper air disturbance rotating around this system will move into our area on Sunday.  Sunday will be mostly cloudy and several runs of the GFS have shown a chance of showers Sunday afternoon.   High 67.

I’ll update Friday evening.


High pressure that brought delightful weather on Friday will drift to our east, allowing a return flow of warmer and more humid air to enter our area.

Saturday will be sunny and warm.  High 85-86.  Dew points will still be in the comfortable range.

On Sunday, a weak upper air trough moves through. Temperatures will increase as will humidity, with dew points moving into the more noticeable 60s.  High temperatures near 87-88.

The weak trough may result in some cloudiness in the afternoon Sunday.  Some weak vorticity also present. The models are showing light showers far to our west, with nothing moving in to the immediate PHL area.  I’ll keep an eye on it.

A stronger front moves through Monday night.


Last Updated

Sat Evening Update: Skies clear early Sunday morning, based on the latest models.

The forecast is little-changed from the forecast “outlook” I posted yesterday.

Friday’s easterly flow will shift to a southeasterly flow ahead of a warm front that attempts to move through Saturday.

Saturday will be quite cloudy; any showers are expected to hold off until Saturday evening and Saturday night.  High 76.

A weak cold front moves through late Saturday night or just before daybreak on Sunday accompanied by light showers.  The front slows as it passes through.

Most models have clearing early Sunday morning, but the latest NAM suggests that some cloudiness may linger into mid or late morning Sunday and longer at the shore.

Sunshine is expected by Sunday afternoon with high temperatures about 82.

Tropical Storm (#09) is expected to intensify off the Georgia/South Carolina coastline.   Most models have it blocked from moving north, up the coastline.  It may become a Category 1 Hurricane.

COAMPS-TC Experimental model Forecast and Track

Tropical storms seem to reduce the accuracy of the model forecasts.  We’ll see how it goes this weekend.

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