You have local connections, so you know the people in Braithwaite and Laplace had a terrible time. For them, Isaac might as well have been Katrina.
My mother grew up on the upper east side, so I have spent some time in NYC from earliest childhood and have a pretty good clue about the ways extreme urban density introduces unique challenges to disaster planning. Of course it makes no sense for such people to prep for a six month horizon, but if they had prepped for just one week, they would be so much better off.
Storm surge hydrology is a science with a long way to go: we discover new ways for people to get flooded every time. This is another reason people with potential exposure (and those presuming to advise them) need to remember to build a safety margin into their predictions. Don't lie to the people, but admit to them your predictive ability is not what you'd like it to be. Forecasters seem to have the concept down when discussing the "cone" and landfall predictions. Of course another thing that has to happen is people cultivating good risk avoidance habits of their own and not overburdening "experts" with more credibility than they can answer for.
NYC proper, especially LI hasn’t had something of this magnitude in a while. Hopefully it will foster a new sense of independence in a few locals. I suspect a good deal of the gas lines in NJ are locals getting gas for their gennies. Which means NEXT time they’ll buy gas, and the appropriate cans, BEFORE hand. I’m working on my local friends to invest in water filtration stuff next. If some of the munis in central NJ run out of fuel or have problems with their backup gennies that’ll go bad in a hurry. They’re all OK wrt food and essentials like firewood and even bottled water. In a ‘one second after’ scenario they’d have to bug out eventually because the lots are WAY to small to grow anything but a few tomatos and herbs.