Just out of curiosity, does anyone in the US use the Aviation Weather Center Graphical Forecast for Aviation, formerly HEMS Tool?
https://aviationweather.gov/gfa/#obs
If you click the layer button, there is a check box for Flight Category. It displays the areas on the map that are MVFR, IFR, and LIFR.
The whole purpose with the development of the former HEMS Tool was to make the decision process easier.