The Ambient Weather sensor arrays are made by FineOffset. FO has a off shoot for consumer sales called EcoWitt. Their GW1000 receives the RF from the sensor arrays. I've tested it with my WS-1401 that uses the Observer IP module and it's a direct replacement.
Point being that with the GW1000 you can configure it to send to a local server HTTP end point. I worked with FO to make the endpoint customizable and port so it can work with multiple systems. You will need a webserver to accept a POST and then parse the incoming data. This makes the entire setup local.
On top of it the EcoWitt stuff is cheaper.