(This is another double post between my weather blog WX-Man.com and Brendan’s)

Dr. Jeff Masters showed this Microwave satellite image of Hurricane Dean from around 7 AM EDT, or as Dr. Masters described it as “Think of this as a weather radar in space.” Like in the enhanced infrared satellite that has been shown here the red areas indicate the thunderstorm convection in the spiral bands and the eyewall. He then points out the the “incomplete double ring of echoes around the dark blue eye. Dean has two eyewalls, concentric around each other.”

This is very interesting to me and I will be the first to admit when I learn something new. I am a meteorologist, but I will be the first to admit that my weakest area in meteorology is Tropical Weather. He has a great discussion on what this “Double Eye” means for Jamaica and the Cayman Islands:

Jamaica is already receiving high winds and heavy rain from an outer spiral band. How bad will it get? The big question is if the eyewall will move over the island. Unfortunately for Jamaica, Dean has two eyewalls, forming concentric rings (Figure 1). The inner eyewall is 15 miles in diameter, and the outer eyewall is 37 miles in diameter. Winds of Category 3 and 4 strength are blowing in both eyewalls, as seen in the latest data from the SFMR surface winds taken by the Hurricane Hunters. So, Dean’s center has to pass more than 25 miles south of Jamaica for the island to be spared the worst of the hurricane. The nation’s capital, Kingston, lies on the southern portion of the island, and will be the hardest-hit major city. The tourist city of Montego Bay is on the northern part of Jamaica, and will fare much better.

The same story holds true for the Cayman Islands. Grand Cayman, the southernmost of the islands, it at greatest risk. If Dean passes more than 30 miles south of the island, they will miss seeing the outer eyewall of Dean and will fare relatively well. It’s going to be a close call, but it appears that both Jamaica and the Cayman will miss seeing the eyewall of Dean.

At the end of this post he gives his thoughts on Dean’s hits on the Yucatan near Cozumel and then south of the Texas/Mexico boarder and how this could be similar to Hurricane Emily.

Also this morning Eric Berger (SciGuy) isn’t ready to clear Texas from being threatened by Dean, but seems to agree a lot with Dr. Jeff Masters:

I’m also not ready to clear Texas yet as possibly being threatened by Dean, although all of the models, at a minimum, now bring the storm in for a final landfall nearly 200 miles south of the border. The models also are beginning to predict some weakening for this final landfall as Dean spends more time over the Yucatan.