We were slapped ahead in time to fall this past Thursday. A sharp cool front that dropped low temperatures in the West Chester area to the mid-40s on Friday morning and near 50 on both Saturday and Sunday—the coolest mornings we've seen since May.
A true taste of fall has been upon us. Coupled with sunshine two of the last three days, the region has had a chance to dry out. Unfortunately, I can't promise a dry week, nor can I promise that these nice temperatures will continue.
A fast-moving pattern in the atmosphere will settle in as the week progresses, with a couple rounds of rain expected. The first should move through Tuesday in concert with a weak disturbance, and it should bring between a quarter-and-a-half-inch of rain to the region.
After that, a break is in order for Wednesday, although a shower or storm can't be ruled out in the afternoon. Then, a second system works into the Great Lakes and brings additional chances for showers and storms on Thursday and Friday. There's uncertainty about how this system moves through—some of the computer modeling that shows this storm system stalling out over the Ohio Valley, leading to a bit of a rain train into the weekend.
However, that guidance has not been consistent, nor is there a consensus of that rain train happening. Other guidance shows that we clear out on Friday night and get a nice Saturday and Sunday. Hopefully, the latter scenario (the dry one) verifies as we really don't need another rain train in the area.
Regarding temperatures, we could flirt with 80 on Wednesday and Thursday locally and should have highs in the 70s on Monday. Tuesday could see our coolest temperatures—possibly upper-60s—thanks to those aforementioned clouds and showers.