I can do all the weather bit with a Jaycar kit. I can talk to it with Cumulus (one of several bits of free read-station and upload-to-Web stuff). The system will use a dedicated onsite PC (we have power) and a cellular modem for uploading to the Web. Cumulus uses a pretty simple approach where it creates the relevant web pages and uploads the html. So there is no need for any server-side programming. Cumulus is template-driven so the uploaded page can be customised. That includes dropping a picture or two into the upload.
Upload to web would be cellular.
The camera bit of the setup should take a picture every so often and save the image in a specified place with a specified name. The (concurrent) Cumulus "build a site" task picks up the image when a web refresh is due, inserts it in the upload and off we go. Refresh every 30 minutes would be fine. The purpose of the image is to give an indication of cloudbase. I would imagine that VGA resolution and relatively low quality would be fine. Data volumes and all that .....
Not sure if a CCTV camera/frame grabber is what I need or should I look at a USB controlled point-and-shoot digicam?