19 October 2005

New record low pressure in the Atlantic...

Wilma has very quickly become a storm for the history books.  At 21Z 
yesterday, the winds were 70kts and the MSLP was 970mb.  It then 
intensified at rates never before seen, bottoming out at 882mb early 
this morning, a new record low pressure (beat Gilbert's 888mb in 1988) 
for the Atlantic.  MSLP fell almost 100mb in 24 hours, and over 60mb in 
just 6 hours!  

Since this morning, the central pressure has held steady at 892mb, and 
an eyewall replacement cycle is beginning, which will weaken it a bit, 
but leave room for future strengthening.  You can view a plot of central 
pressures observed by aircraft at 
http://einstein.atmos.colostate.edu/~mcnoldy/tropics/wilma/Wilma_Recon.png 
(it comes with a humor warning).  The environment continues to be 
flawless for it, and the oceanic heat content will actually INCREASE in 
the coming couple of days.  
http://www.aoml.noaa.gov/phod/cyclone/data/ca.html

At 21Z today, the maximum sustained winds are 140kts and the MSLP is 
892mb -- located at 17.7N 83.7W and tracking WNW at 6kts.  The truly 
remarkable feature is the VERY tiny eye.  The diameter has been as small 
as 2 nautical miles, now at about 5.  This pinhole eye is largely 
responsible for allowing the storm to acquire and maintain such a low 
pressure.

The intensity forecast is basically to remain a CAT4/5 storm as it 
heads toward the Yucatan peninsula.  Cancun and Cozumel are in serious 
danger.  Then if it tracks over land it would obviously weaken quite a 
bit, or if it manages to cross through the Yucatan Channel it would 
weaken only slightly owing to increasing shear and decreasing heat 
content.

However, the track forecast is perplexing.  Model agreement is very 
good in taking it through the Yucatan Channel then recurving into the 
FL peninsula.  However, the northward nudge that has been forecast is 
not happening so far, so how much longer will it resist moving 
northward?  The official forecast does recurve it, making landfall near 
Fort Myers, FL Sunday morning as a major hurricane.
Please visit my tropical Atlantic headquarters.

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