OK SATURDAY, NOT SO GREAT SUNDAY- FORECAST

Sat 08:21 AM Update — As for cloud cover today, what you see is what you get for most of the day. There may be some brighter spots in some areas around 2-3PM, but then lower clouds move in.
Fri 10:46 PM Update — Tonight’s NAM and NAM NEST are more aggressive with the heavier rain making it into Philadelphia on Sunday.  (They are the only models available now that extend into Sunday.) It looks like it will rain much of the day. Saturday’s forecast looks good.  

High pressure has pushed in Friday afternoon and the frontal boundary that has been stalled near us will be pushed to our south taking some of the humidity and showers with it.

The high pressure system will move off to the northeast.   A northeasterly flow of cooler air will be with us for the beginning of Saturday.  Unfortunately, the frontal boundary to our south will still be active and moisture and cloudiness will move in during the afternoon on Saturday as low pressure develops along that same boundary.

Saturday—

  • Some sun very early, then increasing high cloudiness.   Considerably cloudy 12-3 PM. Mostly cloudy after 3 PM.
  • High temp 84.2º sd 1.3º  Dew point comfortable- low 60s.
  • Some showers possible late evening.
  • Winds ENE 5-10 mph, gusty to 15 mph  in the afternoon.

The frontal boundary and the low pressure wave brings rain and showers before daybreak  Sunday.   There is uncertainty about how much rain we will have on Sunday.  The latest GFS is faster with the onset and has the the main batch of rain exiting during the morning.  The model blend and most of the models have rain throughout much of Sunday. 

The model blend (NBM) tends to lag with big forecast changes, as it is based on models run 1-6 hours beforehand.  If there are major forecast changes as the GFS implies, the model blend won’t reflect it at this time. 

Sunday—

  • Cloudy with rain in the morning, possibly ending late morning.  Will need to update.  Cloudy in the afternoon.
  • High temp 75.5º sd 3.8º ( very high uncertainty/spread)
  • Winds ENE 5-10 mph and gusty to 16 mph.

I will do a quick update later this evening with the new model runs.