Merit decisions can come out any time between late October and the beginning of March. If a student receives merit, the notification might arrive fairly quickly after acceptance, or it might take months… so be patient and don’t lose hope. 
Honors decisions come separately from merit. We do not know exactly how honors decisions will be rolling out this year. It seems to be different from previous years since some students have already received their notifications.
Both merit and honors will arrive as an email notification and a letter in the student’s portal.
This is the thread to follow for merit decisions (and people have posted some honors decisions there too): Merit @ Pitt - HS Class of 2026