There is a difference between METAR and ATIS. A METAR is a weather report for the field that can be generated automatically by an AWOS or manually by a National Weather Service observation station. In either case, the data is available over the internet because it is transmitted in digital form to the NWS computer system.
ATIS data (for a controlled airport) is issued by the tower and is manually recorded voice information of one the controller’s speaking. It is NOT automated (except that the tape constantly loops). It does contain METAR data in it, but the ATIS data itself is NOT transmitted electronically over the internet or any other netowrk so you can’t get it. Don’t forget that METAR data changes only with the hourly observation or when a special METAR weather observation is issued for a significant change. ATIS data may change a LOT more frequently as the tower changes runways in use or any other data they put out in the ATIS in real time…
Bottom line – only way you are ever going to get ATIS data over the internet is if someone is recording or streaming the ATIS radio frequency over the net…it doesn’t exist in digital data form.
Dave