Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 2:41 AM GMT on October 20, 2005
Just a quick update on the latest model runs: The 18Z (2 pm EDT) runs of the GFS and GFDL models have swung back towards Florida, and predict that the Yucatan may only get a quick (but severe) blow. The amount of weakening that might happen with Wilma over the Yucatan for just 12 hours or so is difficult to gauge. Also, there is the possibility of a threat to New England--the latest GFDL model run has Wilma hitting the Cape Cod area as a Category 2 hurricane on Monday night. I'll wait for the 00Z (8pm EDT) runs of the models that will be available in the morning before commenting more. The degree of uncertainty in both the track and intensity forecast of Wilma remains very high. The remainder of my blog from 5pm is below, unchanged.
Hurricane Wilma continues across the western Caribbean towards Mexico as a Category 5 hurricane. The Hurricane Hunters reached the storm at 2:06 pm EDT, and reported a pressure of 892 mb, ten mb higher than the Atlantic record lowest pressure of 882 mb set this morning. The 3:56 pm EDT hurricane eye report showed the same pressure, 892 mb. Peak winds measured at flight level were 141 knots in the southern eyewall, compared to 162 knots measured this morning. Infrared satellite imagery shows that the cloud tops have warmed a bit since this morning, and Wilma is a weaker storm--but still a Category 5 capable of catastrophic damage. The eye diameter measured by the hurricane hunters was still a very tiny 5 nm, and an second concentric eyewall with diameter 10 nm has formed. This indicates that Wilma may soon undergo an eyewall replacement cycle, and will weaken to a Category 4 storm.
Figure 1. Computer model tracks for Hurricane Wilma.
Where will Wilma go?
There is now a high degree of uncertainty in the forecast for Wilma. NHC has not adjusted the official forecast much with the 5 pm advisory, other than to slow down Wilma a bit. However, a major shift in the model guidance occurred with the just completed 12Z (8 am) runs, that may force NHC to make major modifications to the official forecast if further model runs continue to show this shift. Three of the top models--the GFS, GFDL, and UKMET models--now show that the trough of low pressure that was expected to pull Wilma sharply northwards and then northeast across Florida is progressing slower than expected, and will not dig as far south. If this forecast verifies, it would be very bad news for Mexico. Wilma may not pass east of Mexico through the Yucatan Channel as originally thought, and may instead make a landfall on the Yucatan Peninsula near Cozumel or Cancun Island on Thursday night or Friday morning, probably as a Category 4 hurricane.
However, this would be very good news for Florida. A long encounter with the Yucatan Peninsula would cause a serious disruption of the hurricane, and make it unlikely that Wilma could affect Florida as a major hurricane. A hit on southwest Florida as a Category 1 or 2 hurricane would be more likely, and the arrival of the hurricane would be delayed until Sunday. So, if I lived in Florida and was thinking about evacuating today, I would wait another day and see what the forecast tomorrow brings. Keep in mind, though, that the NOGAPS model, which is one of the top four models for tracking hurricanes, is still showing that Wilma will pass through the Yucatan Channel and a make landfall in southwest Florida as a major hurricane. The Canadian model is showing this as well. And the worst possible scenario, where Wilma makes a direct hit on Cancun but only spends a few short hours over the Yucatan and does not significantly weaken, is also a possibility.
Conditions on the Yucatan
Here's an email I received from wunderphotographer cleo85 , who is in the Yucatan and took the photo shown below. She has promised to post photos and send reports as her situation permits:
"Here is the Paamul [Yucatan Peninsula] update. After a very cloudy morning we did have some blue sky around 11:00am CDT. Now at 2:00pm CDT the Sky is almost overcast with picturesque clouds. There are a few light showers. We have a light breeze from north with winds what feel more and more warmer. The morning [5am CDT] showed 76 Fahrenheit now we have 88. Paamul is boarding up and will evacuate tomorrow. There is a confusion were to go since some of the newest computer models showing landfall on the Yucatan with a turn around and going back to the Caribbean. I was told the mood in the city of Playa del Carmen changed from almost ignorance two days ago to panic right now. There is no gasoline or diesel anywhere between Cancun and Tulum. Groceries seams to be tight. Batteries are out. There is price poaching going on. The Newspapers do their best to bring the panic up."
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