How do I let my boss and co-workers know I got a job transfer when I was just changed over from an intern to a fulltime employee?

I was hired last summer as a gov intern and currently in the process of switching over to a full time employee as I graduated from college. I've been driving 5hr/day when I have to go to office (once or twice per week due to covid) as I couldn't afford housing near work on intern pay.

This month, I passed the interview at a branch closer to where I currently live. This branch is currently waiting for my full time employee document to come out, so they can switch me over (easier to process it that way). After that it'll probably take a few weeks to send out my actual job offer.

I'm really thankful of what my work has offered so far, but think the new job is better economically and physically. However I feel really bad at my current location as it took a lot to train me, send me on business trips, and my boss really looks forward to me finally working there as a full time employee.

My questions are: When do I start telling my boss about the transfer during covid? (Standard 2wk via call or email?) How do I lessen the disappointment?
We have a weekly team telecon, what do I say during this telecon when my boss asks me to about my leave?
Any other advice will be helpful.

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official