Monthly Archives: May 2017

Philadelphia Area Weather Forecasts

Much Cooler Weather for the Weekend

Updated 8pm Friday in italics

A weak cool front has moved through on Friday and winds have shifted to the west.   High pressure will nose down from the north  and will be over our area on Saturday.  Circulation around the high will be from the east, giving us significantly cooler conditions.

Saturday will start with some clouds, but skies will quickly clear as an easterly flow develops.

The GFS clears us out on Saturday, but the latest NAM suggests the chance of some brief showers about noontime on Saturday as the winds shift to the east.  It’s beginning to look like there may be considerable cloudiness on Saturday.

The high drifts off on Sunday and low pressure attempts to move in from the west.  Sunday will start sunny, but an increase in clouds is expected  during the late afternoon with a chance of showers early evening.  Highs near 68.

This weekend’s forecast is above average confidence, although easterly flows sometimes results in more clouds than forecast by the models.

(Some heavy rain expected for Monday.)

Weather Updates

Sunday Weather Update-

With low pressure off of Cape Cod on Sunday, upper air disturbances (vorticities) will rotate through our area on Sunday.  Timing of these upper air vorticities is difficult to nail down, but the NAM and to a less extent, the GFS, has a disturbance rotating through between 2 PM and 5 PM on Sunday.

Below average forecast confidence for Sunday, but best guess is that early clouds break for a mix of sunshine and some clouds in the morning and early afternoon.  Cloudiness increases during the early afternoon and the upper air disturbance moves through between 2 and 5 PM giving us a chance of widely scattered showers.  High temps near 70.