Maybe I’m misunderstanding. I grew up in NYC, and “father” absolutely does rhyme with “bother”. Just listen to Run DMC: “they even bother my poor father cause he’s down with me.”
Looks like the difference is between the rounded and unrounded back open vowels /ɑ/ and /ɒ/. This site has an IPA chart where you can hear the differences. The father-bother merger hasn't happened in my (NE) accent, but I didn't know that pretty much everywhere else merged the two. Interesting that cot-caught merged for NE but not father-bother.
Younger New Yorkers do have the father-bother merger, but older New Yorkers don’t.
Also, Run DMC probably speak African-American English, which, as this map says, is generally independent of other dialects and not included on this map.
Kinda makes sense, though. You can fly from the west coast of the US to South Africa in under 24 hours. Areas that used to take weeks, months, and even years to get to are now under 24 hours and largely less than $5,000 to travel to.
We are gonna get some wild pandemics since anyone can criss-cross the globe so fast.
Interesting how Washington, DC used to be within the Southern accent territory, but this has died out to mostly older speakers.
The anecdote that really hits this home for me is that in 2006 they updated the voice on the metro which said "Doors closing, please stand clear of the doors." The old voice had a southern accent but the new voice did not.
It reminds me a lot of ourdialects.uk which does similar but for the UK and split across a few different maps. I'd love a website where it guesses where you (or someone else) are from based on some sort of quiz.
I think most of this is going over my head, but I'm especially trying to wrap my head around The Midland exclaves for San Francisco, El Paso, and Tallahassee.