"pa" would be pronounced between these two, depending on speaker:
/pɑː/ — if I had to use "normal person's IPA", "pah" would be my attempt. This, to me, is the more common pronunciation. Should rhyme with "bra" … assuming you pronounce that like I do.
/pɔː/ — like "paw" or "awe". This is a region-specific dialect, to me. This appears to be the one you're familiar with.
/pɑː/ — if I had to use "normal person's IPA", "pah" would be my attempt. This, to me, is the more common pronunciation. Should rhyme with "bra" … assuming you pronounce that like I do.
/pɔː/ — like "paw" or "awe". This is a region-specific dialect, to me. This appears to be the one you're familiar with.
See https://en.wikipedia.org/wiki/Help:IPA/English for a chart.