This actually took some non-trivial effort to do. The weather.gov API isn't 100% reliable, so it needs to start trying to pull weather data about 15 minutes ahead of time. It also needs to actually post at 8:47 AM MST / MDT, in a land where most of my server stuff is UTC. Over half of the code is just figuring out when to do stuff.
Here is the script, using my homegrown Mastodon bot framework: https://github.com/rfinnie/mastodon-apps/blob/main/mastodon_apps/eightfortyseven.py