Philly Weekend Weather Outlook

High pressure that has been dominating our weather Thursday and today, Friday, will move off to the east today, allowing a weak warm front to pass over Friday night.  An increase in humidity and clouds will be noticeable tonight and Saturday.

Saturday will be affected by the lingering weak warm front  boundary, diffuse weather features, and a moist flow of air from the south.  Considerable cloudiness is expected on Saturday;  there will likely be  bright spots and breaks of sun mid-day, but an increasing chance of showers/thunderstorms is likely later Saturday afternoon and evening.  Most of Saturday will be rain-free, but wherever scattered thunderstorms do develop, heavy downpours are possible. There won’t be any distinct location-predictable triggers for the showers much in advance.

It will be very warm and very humid Saturday (dewpoints in the low 70s) but the cloudiness is expected to reduce high temps to about 88.  If we get more sun, temps may raise above 90.

Sunday currently looks to be be partly sunny, hot and very humid. High in the low 90s and dewpoints in the uncomfortable 70s. Scattered showers and thunderstorms possible, but much of the day rain-free.

The weak summer pressure pattern has caused the model forecasts to have been anything but consistent for this coming weekend’s weather, (even this past week’s forecasts have been less than stellar).  Expect changes in the forecast each day. A lower than ususal confidence forecast this weekend.