It needs some significant improvement for US based warnings as well. The warnings displayed are extremely inconsistent in severity as compared to NWS CAP, and often times the warnings / advisories / watches are completely missing in patches throughout the map. I double checked NWS CAP and they are indeed correctly being sent through there. Some of the watches and warnings are also duplicated for some reason on windy.
For example:

Compared to the watch area here:

This is the NWS CAP XML index for Georgia at the time: https://feen.us/m3r4q5m5mn3ofq25n8f8.txt
And an example CAP message for the tornado watch: https://feen.us/91tota6stvd3v0oqj4le.txt