There are greater uncertainties forecasting the weather during the springtime as large scale weather determinants become increasingly influenced by smaller scale (mesoscale) effects.

Such is the case this weekend, with the NAM and GFS models having different forecasts, especially for Sunday.  Basically, cold high pressure moves off to the east, allowing low pressure to approach from the west.   The GFS allows this low pressure to give us a chance of showers on Sunday, especially to our south.  The NAM suppresses the low pressure system to our south, keeping us dry in Sunday.

The NAM model has done well lately and I’m going to go with that model.  Saturday has a mix of sun and clouds.  High 62.   Sunday has mostly cloudy, some breaks of sun.  High 65.    If the GFS verifies, then Sunday will be much cloudier with a chance of very light showers, especially south of PHL.

Saturday AM update:  The GFS has joined the NAM in keeping the rain to our south on Sunday.  Sunday will be partly sunny/partly cloudy with temps near 65.    There remains uncertainty about the amount of cloud cover for both Saturday and Sunday.