WARNS can be handled in 2 ways.
One. a 60 day notice of a layoff is handed to employees. This happens the same time time that a WARN Act notice is sent to the state.
Two, employees are laid off with no notice but employer has to pay severance pay to the employee equal to WARN Act 60 day notice period.
Some states have higher time limits than the 60 day period so which one that longer time limit is the one that takes precedent
https://en.wikipedia.org/wiki/Worker_Adjustment_and_Retraining_Notification_Act_of_1988