wrote:
If I want to talk to Flight Watch to get an update on the developing
weather situation or give a PIREP, how do I do that?

Just tell them you'd like to leave the frequency to talk to Flight
Watch for a couple of minutes. Either they'll say no, or yes and
perhaps a time limit, or if you're really lucky they might ask what you
need to know and get the info for you.

Of course, in the New York City area, you can get handed off between
frequencies so often, there's not much chance to go off-frequency ;-)

Cheers, Kev