Those increasing clouds to our west this evening were in advance of a cool front that's in Central Pennsylvania. As we talked about earlier today, the front that's approaching the region is losing some of its punch. Temperatures behind the front won't be dramatically cooler (mid and upper 70's this weekend for highs) than they were ahead of it...and the front does not have a ton of precipitation with it.
In fact, this is it as of 8 PM.
The front has a band of showers stretching through Pennsylvania, moving slowly eastward. It should cross the region after 11 PM from west to east. Could bring a few showers or a generalized sprinkle to those of you north of the city tonight. It shouldn't produce much in the way of rainfall as it moves through.
However, the next system (starting Monday night, continuing into Tuesday) will likely have more bite and bark with it as it brings the potential for some more significant rains, especially west of the city.