You’re favorite days, the days when the south shore shoots well over 100 on a strong offshore flow often see brutally cold water temps. Near shore water temps were in the low 60s on the hottest day of the June heatwave with tons of upwelling. Super shock from the system to go from 100+ on the sand to water that chilly.
The Gulf Stream is too far offshore to have any real effect on our waters. It follows the end of the continental shelf. Occasionally an eddy will spin off that gets relatively close.
As far as effects on tropical activity, our exposure to a major is increasing. We have always been able to support a major up to the latitude of the Gulf Stream but then had a nice buffer to weaken storms that weren’t rocketing north like 38. Out waters still technically can’t support a major (allot of it is depth related) but the weaking effects of water around 26c aren’t that pronounced.