by Jay Reynolds Freeman
I went to Michelle's Saturday, and had a fine night. I left the bay area late in the afternoon (figuring there wouldn't be much for me to do before moon set), drove down 101, and out through Pacheco Pass. Satellite images for the day showed persistant cloud cover over the coast, but only a few wisps trailing out toward Yosemite. When I left, the south bay was overcast, there were breaks in the overcast by the time I was driving down the Santa Clara Valley, but the peak was partly obscured by cloud evidently clinging to it, and had a cloud cap above. More relatively thick stratus clung elsewhere over the coastal hills.
Going out through Pacheco Pass, the broken cloud persisted, and the highest hills on either side had wisps of cloud about their summits. However, the overcast cleared as I crossed the valley, and the sky was clear and dark from Mariposa. A few high cirrus drifted past as I set up, but by about 1030 or 11 PM I was in business under clear sky.
Humidities were very high -- they started in the low 80s and rose to 98 percent (relative humidity measured on the Radio Shack gadget I carry). Temperature remained relatively constant at about 8 C. At 0230, thick stratus appeared above and west, and descended onto Michelle's place as fog. I was about to take down anyway, but by 0300 or so, the fog had settled below our level -- I found it in the valleys as I drove back to my Mariposa motel room -- and it was clear again!
I will post an observing report later, but I thought these observations on weather might be useful.
BTW, despite the humidity, my Kendrick anti-dew system and Orion Flexishield kept my C-14's corrector plate dry. The finders dewed up, but most of my evening was a long star-hop across northern Leo, so I scarcely needed them. I kept mittens over them to dry them out. I had a Kendrick gadget for eyepiece dewing, which I also encountered, but rather than use it, I took the dew as an excuse to sit in my car, drink coffee, and warm things up for a while.
Michelle did not have a Kendrick for her C-14, and was dewed out by the time the fog settled below us.