I've just written a WeatherCat to MQTT bridge using the excellent WeatherCat Applescript interface.
MQTT allows lightweight publish and subscribe functionality and is used for process control, Arduino projects and lots of other fun things. The bridge I've written uses the open source MQTT tool Mosquitto
It's not just the tides for Merewether but its the tides for Newcastle (which, lets face it, is pretty close). So you could use it for Stockton, Nobbys, Newcastle Beach, Bar Beach / Cooks Hill, Dixon Park Beach, etc.
The Merewether Tides are generated using data massaged from the brilliant program XTide