Port Forwarding
From WeatherCat Wiki (Mahler)
To be able to access WeatherCat from outside your local network, you will need to port forward ports 49250 to 49254. Note, for WeatherCat 3's rich client protocol, port 49255 also needs to be open. The links below show the settings for various routers - for WeatherCat 3, in all cases the end port needs to be 49255, not 49254 as shown).