METARs, TAFs, the area forecast (FA), and flight service briefings are great tools, but if I'm planning a flight with an overnight stay (or a flight that itself might take me a couple of days of travel time) I often feel that the weather picture I'm getting is a little too short-term for my liking.
Aside from watching The Weather Channel are there any supplementary weather sources I can look at which are useful for aviation/flight-planning purposes?
I'm interested mainly in resources for the USA but answers for other countries would be interesting too.