With apologies to Andy Williams, this coming week's weather may be the "most wonderful time of the year" since humidity levels will be low, sunshine will be maxed out, and that general September feeling of weather win will dominate the region. The front end of this week of wonderful weather will be punctuated by cool, crisp mornings between Monday and Wednesday. Lows in the city drop below 60 for the first time since June, with the potential of outlying areas dropping into the 40's on Monday night!
The NAM (shown below) shows the potential for that cool, crisp start on Tuesday morning below as the dark green shaded areas are temperatures in the 40's, with 50's in the lighter green. Yes, those are even some 30's in the dark blue across the Twin Tiers of Pennsylvania and New York up near Binghamton. It would not surprise me to see Mount Pocono drop below 40 on Monday night as the core of cool moves overhead.
Essentially, expect 70's through Tuesday for highs with dew points in the 40's and low 50's, followed by nighttime lows in the 40's outside of the city and in the 50's in Philly for both Monday and Tuesday nights.
As high pressure pulls off the coast, temperatures will moderate and we will see a warming trend of sorts take over for the duration of the week. Highs will bounce back into the 80's on Wednesday, where we'll generally reside until the weekend. However, humidity levels will be much lower than they were last week so the end result is a comfortable but warm second half of the week.
A cool front will try to push in from the west for Friday and Saturday, with the front triggering a shower or storm chance around the region on Saturday afternoon if the GFS is right. That's still several days away and the front as depicted on the GFS isn't expected to be terribly potent. The result should be a week of the nicest weather we've seen around here in a while, with relief from the muggies upon us.