What would happen

[Matt-hurricanewatcher]

What would happen if the hole western Caribbean one of these seasons had waters over 100 degrees f. I mean from central America to Jamica to Cuba to the north. In a system moved into it at a time of shear less then 5 knots and with perfect outflow. How powerful could this cane get?

Also with 26c sst's going all the way to the bottom.

[WindRunner]

Depends on what kind of Maximum Potential Intensity(MPI) formula you'd like to use. I know around here people like to use Kerry Emanuel's that is here, which seems to work pretty well in the real-life applications we put it through.


I did find a good paper on the analysis of MPI formulas for TC's - it's not a bad read (read it here). Of most interest to you would be the last 3-4 paragraphs in section 3 and most of section 4. Section 5 is the simplified conclusion and brings some good points out of the equations if you just want a quick glimpse at what's being said. Just search for "hypercane" and go from there - it'll put you in a good spot to start.


Bascially, though, it mentions that SST's beyond 28°C, and especially 30°C, will not increase the potential intensity of a storm and that there is most likely a limit to the intensity that is approached beyond that point. It also mentions that one of Kerry Emmanuel's older (1991) formulas, when altered to give a SST of 40°C in the South Pacific, provided an eyewall pressure of 815hPa and a central eye pressure of 622hPa . . . and that the equation broke when SST's were changed to 42°C.

In practicality though, it doesn't seem like such a setup would have a huge impact, other than providing no reason for the water temperatures to limit what the other nearby environmental variable would allow. And of course, we must also remember that 38°C water temps aren't likely to happen in today's world . . . so it only makes sense that we don't see any reason for such ridiculously high temperatures to effect our thoughts on maximum TC intensity.

[Matt-hurricanewatcher]

Thank you Windrunner for the great info. But parts of the gulf and caribbean some time get into the 90s. The arabian gulf some times tops 100, so its not impossible but just very very hard.

[wxmann_91]

Theoretically, SST's could be too warm and instability too high, leading to repeated reformations of outer eyewalls. An endless repetition of ERC's.

[Ptarmigan]

SST is not the only factor. Certainly, warmer SST would have an impact. It depends on how deep it goes. If it is shallow, upwelling would weaken due to cooler water.

[WindRunner]

Thank you Windrunner for the great info. But parts of the gulf and caribbean some time get into the 90s. The arabian gulf some times tops 100, so its not impossible but just very very hard.

The thing with the gulf is the fact that that is literally SST's (surface only). More than a couple of feet down from the surface you hit more reasonable mid-80s temps. As for the Arabian Sea, yeah, it gets hot . . . though those near-100 temps are more common in the Persian Gulf, where the driest air in the world and a small body of water prevent things from existing. Arabian Gulf itself is rarely hotter/rarely has more TC heat potential than the WPAC.

[Aslkahuna]

Actually, the air over the Persian Gulf region is the most humid on the Planet with average surface dewpoints in the 80's during the Summer and peaking in the 90's. It's the very warm air aloft and subsidence that prevents precipitation. We have a similar thing going on here in AZ today-we have PW's of 2.00 inches and dewpoints in the mid to upper 60's and yet very little activity outside of mountain buildups because of -3 to -4C H5 temperatures. THIS is how you can have humid deserts with little or no rain.

Steve