Subject: Re: Offshore vs nearshore sonde composite Date: Sun, 4 Aug 2002 12:39:33 -0400 From: "Peter Black" To: "James Franklin" CC: Colin J Mcadie , Edward N Rappaport , Richard J Pasch , John L Beven , James M Gross , Brian R Jarvinen , Mark Powell , Max Mayfield , Christopher Landsea James and all- Great detective work James, and an excellent composite. This is very revealing to me. Take it for what it is worth, but your nearshore/offshore sonde ratio is exactly equal to the ratio I estimated from composite ratios of hurricane over land gust factors to hurricane over water gust factors, as per the first paragraph in my Andrew Cat 5? report: " Powell shows how this average (the the peak 1-minute average flight level wind) represents a 10-minute average over-water wind at 10 m at a fixed point. To estimate a 10-minute average surface wind over land at 10 m, the average ratio of the 10-min overland (open terrain) wind to the 10-min over water wind first needs to be multiplied. This value is 0.92 ± 0.08 according to Black." So where do we go from here? 145 kt X .92 = 133 kt = CAT 4. My suggestion is to follow the line of thinking I outlined for estimating a 1-min sustained wind over land. That would still result in a CAT 5 conclusion, but maybe another line of thinking needs to be worked out. Congrats to Mark for raising this issue and to sticking to his guns in the face of a withering cross fire. And congrats to James for so quickly digging into the data base and taking an objective look at the evidence. This is the way consensus ought to work. I think everyone will be satisfied that no stone was left unturned, whatever the final decision turns out to be. Regards- Pete. Peter G. Black Hurricane Research Division NOAA/AOML