Well, all the data should be here in ready to draw KML format: https://ocean.weather.gov/gis/index.php
The top item "Unified Surface Analysis" should contain the long/lat coordinates of the fronts (likely just a list of the positions of the blue / red / orange symbols of the front).
If Windy don't care to develop this, it would make a neat project for some budding meteroligist to develop as a Windy plugin: https://api.windy.com/
(As you may infer, I haven't actually explored this any further than writing this post, so be sure to check feasibility prior to committing. One issue I forsee is that this data is only updated 4 times daily, and it would be hard to animate them for all the inbetween times that Windy displays.)