If you look outside now (noon), the obvious feature is thick, high clouds coming in from the south. But here's where the transparency forecast on Clear Sky Clock actually looks encouraging for tonight. The forecast model appears to be initialized very well, matching the current satellite image. It shows the band of clouds about 200 miles wide moving rapidly to the north and east, and (hopefully) away from the Farnsworth Ranch site by 10 p.m. Of course, there are several hours of uncertainty, so it will be interesting to see when it actually clears tonight. For people at the site doing a two-nighter, the clouds are presently offering relief, keeping the daytime temperatures down in the chilly low-90's. Tom -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.