There's a couple things to consider here, how does Germany shape up in the absence of Hitler? If it's a DNVP type party that takes over and regains some German territory(maybe Anschluss?) and eventually stops when faced with the Allies, then Jews will probably remain large populations in parts of Eastern Europe. Depending on how exactly the altered history of the Balkans and Eastern Europe shape up you could probably see some Jewish migration to either Mandatory Palestine, or further West as allowed. The US almost certainly has as big, if not bigger, of a Jewish population due to more gradual, but steady immigration. However, one has to consider how the absence of WW2 is going to affect the US politically, as without the Third Reich to ideologically oppose the US could retain many of its immigration restrictions for quite awhile.
Overall, more Jews all over, less Jews in what is now Israel. Immigration to the region almost surely continues, albeit slowly, and the tensions that creates will rise accordingly. But without WW2 taking place decolonization is going to be different, and the British might be more willing to try and mediate or at least manage Jewish/Arab relations.
I also see Jewish culture being a lot less cohesive as the Holocaust plays a large role in the Jewish identity. Those Jews ITTL would be more secular, but those remaining in Eastern Europe would still be Orthodox/Conservative. Maybe more integration for the Jews in the West while those in the East remain distinct, as they have for centuries?
There's a LOT of factors at play here due to the spread of the population and how things developed post war in the ME.