That’s correct, nor can the regional weather network mesomaps take data from WeatherUnderground nor APRS/CWOP data from findu.com.
You’ll need to publish to your own personal weather website in order to submit conditions to join the regional network.
One of the purposes of the networks is to increase visibility of your personal website by linking from other sites, so that only makes sense if you have a personal weather website 
Best regards,
Ken