This weekend is not going to ideal for sky watchers eager to see the supermoon as well as the beginning of the Perseid meteor shower. Clouds and rain will obscure the view at times on Sunday night. Also, the bright and big moon will add more light to the sky, which will keep us from seeing the meteors quite as well. Here's how it is all going to coincide:
Supermoon rises at 8:13PM on Sunday night. It will be covered by clouds at times, but I do think we'll see some breaks to see the brilliance of the biggest and brightest moon of the year. It will appear only 12% bigger, but 30% brighter than normal! The Perseid meteor shower will be starting, but not peaking on Sunday night. The peak of the meteor shower will come Aug 12-13, and the moon will be a bit smaller and fainter by then. Expect about 100 meteors per hour on Tuesday night! Best time to view will be around 2am.
As for our rain situation, it looks like Saturday will still be pretty much a washout. Rain will be likely early in the morning, then again in the afternoon. A few t-storms could develop late afternoon as well. Saturday night into Sunday should bring a lull in the rain, then a few more showers and storms will develop late Sunday. By the end of the weekend, the Upstate will likely total up about 2-3" of rain, and the mountains should see similar totals. Flooding doesn't look like a major concern, but some isolated road flooding and high rivers/creeks will be possible. The saving grace is that the rain will move through in waves, so we should get some breaks in between. This will help our drainage systems catch up.