Pressure question...

[nickd]

I have looked at a few recent major hurricane strikes on our US coastlines. For example, Hurricane Andrew was a Cat 5 and the pressure at landfall was 922mb. Hurricane Charlie was a Cat 4 with pressure of 941mb. Hurricane Ivan was a Cat 3 with pressure of 931 mb. Hurricane Katrina has a pressure of 919 mb with winds of 145 mph. Is it possible that these wind estimates could be 10-15 mph off? I would think that with a pressure this low the winds would be higher. I realize it was a weakening storm but the winds dont match with the pressure reported. I would like an experienced met to explain this discrepency to me. I am confident that there is a sound explanation to this.

[gtalum]

Wind speed is a function of both pressure and the size of the storm. A bigger storm requires a lower pressure to reach the same velocity as a smaller storm.

[P.K.]

So for instance to achieve the same wind speed within Tropical Cyclone Tracey (217kph gusts with gales extending out 40km) a system say as large as Typhoon Tip would require a much lower pressure. Although the background pressures would also play a part in this strength.

Image comparing Tracey and Tip