Need a pro take on a tropical hypothesis...

[CAL]

Hi all! Here is something that this hurricane season inspired me to begining working on back in early september. Would someone mind taking a look at this and giving me some feed? By all means, shoot me down quick if I am off my rocker. Any input at all is more than welcomed. I Sure appreciate it.




Rapid Intensification Tropical Anomaly



Chris Lisauckis
October 2005

The Rapid Intensification Tropical Anomaly or "RITA", named after the fourth strongest Atlantic hurricane, is an experimental formula that uses a simple linear mathematical function to predict Maximum Potential Surface Gusts (MPSG) in association with rapidly deepening hurricanes. It has not yet been determined if this method can be employed in situations where the minimum surface pressure is higher than 975 mb. The function was determined by utilizing a vigorously intensifying 940 MB hurricane with surface gusts to 175 mph as a standard mean. A variant of 1.386 mph was used per millibar deviated from the aforementioned standard. Remember, an Atlantic basin cyclone must be deepening explosively for this to technique to be considered. Explosive deepening is classified as a drop of 2.5 mb/hr for at least 12 hours or 5 mb/hr for at least six hours (National Hurricane Center).


Negative correlation calculations....

Pressure (MB) and MPSG (MPH) {1.386 mph / mb}

975 (MB) - 126 (MPH)
960 - 147
950 - 161
940 - 175
930 - 189
920 - 203
910 - 216
900 - 230
890 - 244
880 - 258
870 - 272


Maximum Potential Surface Gusts in legendary hurricanes using the anomaly....

Hurricane Gilbert - 246 mph
Hurricane Andrew - 201 mph
Hurricane Charley - 174 mph
Hurricane Katrina - 227 mph
Hurricane Rita - 234 mph
Hurricane Wilma - 255 mph

[Derek Ortt]

I do not like using pressure at all. You should use the pressure gradient

[WxGuy1]

I echo the thoughts of Derek. This is a very difficult project, since even pressure gradient doesn't seem to work at times. For example, Wilma was <900mb, had a TINY wind field (hurricane force winds on to 15 miles outside of the eye), and yet "only" had 175mph winds. Heck, there have been other Cat 5s with 175mph that had considerably (20+mb) higher pressure and a larger wind field, both of which should have acted to decrease the pressure gradient. There are PhDs working on this issue, and there remains MUCH that we just don't know. For example, winds changes tend to lag pressure changes. Given past hurricanes, I would have expected ~200mph sustained winds from Wilma, but recon didn't finds winds to support that. Not to discourage you, but there are problems understanding how winds respond to pressure changes in "normal" hurricanes, much less one with rapidly changing intensity.

[P.K.]

Have to agree with Derek here, the PGF is the important factor for the wind.

[CAL]

Thanks for the input!

[tampaflwx]

correlation does not necessarily imply causation! and in these cases, there often isn't even a strong correlation between the pressure and wind speeds among very intense hurricanes.

[Wirbelsturm]

If recon would've made another pass, they would likely have found stronger winds. Not?

[WxGuy1]

If recon would've made another pass, they would likely have found stronger winds. Not?

Perhaps, but they may have found an even lower pressure, in which case one would expect even stronger winds, so we're still back to a poorly understood pressure - wind relationship.