Otis intensified an insane 60 kt (70 mph) in just 12 hours from 12 to 00 UTC (8am to 8pm EDT). That is the second fastest rate of intensification ever seen in the Eastern Pacific, behind only Hurricane Patricia from 2015.
And we know how that turned out.
What's worse is that all of our computer models absolutely whiffed on this one. Barely any of them showed any strengthening at all today, much less to the category 5 monster it is now. This is truly an absolute worst case scenario as it appears to be headed straight for Acapulco, which has a metropolitan area of over 1 million. Because the models performed so poorly, they've had barely any time to prepare for anything stronger than a minimal hurricane. They also have essentially zero history with strong hurricanes in this part of Mexico, so there is no local knowledge of what to expect and nothing is going to be built for anything close to this.
This is fascinating from a meteorological standpoint in terms of the rapid strengthening and how poorly the models did, but this has the potential to be one of the worst natural disasters in recent years. Hopefully they are spared the worst of it.