GEFS Chart Bot
Polls https://www.tropicaltidbits.com/storminfo/11L_gefs_latest.png, but it can really be used to monitor/notify about changes to any file on the web (including other weather charts).
Made to keep our hurricane Irma channel up-to-date about projected storm paths, and the only dependencies are on python-slackclient, python-requests, and Etag-Monitor (which is bundled in this repo as a submodule).
If you're planning to run your own instance, a crontab appropriately adjusted for EST may be found in crontab.txt.
(c) Charlton Trezevant 2017 MIT License
Enjoy!