Here's a slightly wacky thing I do occasionally:
Get ISS fly-over data for your location from HA:
http://www.heavens-above.com/
If there is a suitable ISS pass, there are 3 alternating-view cameras mounted outside the ISS - and you can look down at your local cloud conditions.
http://www.ustream.tv/channel/iss-hdev-payload
Can be really helpful & is in real-time - you can see cloud cover a few hours before your hoped-for astro set up!
Dean