Case In Transit

I contacted NVC a few days ago to inquire about my approved fiance visa. The last update that I got was a letter from USCIS stating that my case was approved and would be forwarded to NVC. I had no idea if NVC had received it or not. However, NVC responded and said that my case was received and will be forwarded to the embassy where the interview will take place. I also got a case number. When I tracked it on CEAC, it said ‘In transit’ My question is, how long will it take to ‘reach’ the embassy or how long before the embassy contacts me?