As has been previously stated, the only place you’ll find a B-2 squadron “stationed” (as in permanently) is at Whiteman AFB. This does not prevent the B-2 from being “deployed” to Diego Garcia, Guam, or wherever during an exercise or campaign.
As for the flights over Stewart in NY, here’s my guess: they are training flights, and most likely checkrides. Despite the B-2 being the latest, state of the art airplane the Air Force still has its “inertia”, “sacred cows” or whatever you want to call it. It says that certain things get done certain ways. And every Air Force pilot has to have at least one checkride every 18 months (or annually, depending on the weapon system). There are different types of checkrides - the “mission qual” checkride, which means go do your mission with an evaluator watching: ie, drop (simulated) bombs in a B-2, airdrop something in C-130, give some gas from a KC-135, fly with a knuckleheaded student in a T-1, etc.
The other checkride is the “instument/qual” checkride - ie fly your airplane with simulated emergencies (an engine out, for example) and fly instrument approaches down to minimums. This shows that AFTER you’ve done your mission and the weather turns crappy at X AFB you can still bring the airplane home safely.
These instrument/qual checkrides tend to develop a life of their own - ie the evaluators come up with a “profile” to challenge the pilot getting the checkride. The most basic tenet is that the checkride happen at someplace OTHER than the home base - after all, everyone is familiar with the approaches at (for example) Whiteman, because they fly them every time they come home. How about going to, oh let’s say…Stewart for the checkride? It’s an “unfamiliar” field, it’s still in the US and it’s in fairly uncrowded airspace so you can get the practice approaches you want.
My guess is that the B-2s in NY are doing checkrides or practicing for checkrides. I doubt if the B-2s actually park at Stewart, but rather they just land and then taxi back for another takeoff.
As for B-2s diverting due to weather, Minot, McGuire, Dover…all of these are legitimate weather alternates. The requirements for a weather alternate (military-wise, not weather-wise!) are usually less restrictive than the destination. For example, in the C-141 we could designate a civilian field (ie Philly) as an alternate if no suitable military field qualified weather-wise. I’m sure the B-2 can designate military fields without the “super-protective” B-2 hangars as an alternate and use them if the weather crumps at Whiteman.
Wow…long post. Consider yourselves experts on Air Force checkrides now!