Oct 26, 2011

DAY 147

Hurricane Rina was able to slowly strengthen throughout the day, and is now poised to become a major hurricane. It will likely be able to do that within the next 3 to 6 hours. The NHC is forecasting Rina to top out as a weak Cat 3 with maximum sustained winds of 115 mph. She will likely only be able to sustain herself for 1 more day before conditions deteriorate and begin to break her down. Rina's eye has been wobbling all day and has not been able to tighten a perfect spin yet. 

(Hurricane Rina)
Rina is a very small hurricane. She has built up a wall of storms mostly surrounding her eye now, and has been able to fend off most of the dry air that is leaning up against her north and west flank. That dry air has managed to disrupt her feed from that side though. Her strongest feed is from the south, probably aided by Pacific moisture. She is also benefiting from some of the warmest waters in the Caribbean in that location. Even though she has not moved much over the last day or so, upwelling shouldn't be much of an issue in that location due to the greater depth of warm water there.

(Hurricane Rina Microwave)
It now looks fairly certain that Rina will strike the edge of the Yucatan as a Cat 3 or strong Cat 2 hurricane on Thursday. The NHC's Tropical Analysis and Forecast Branch is calling for 8-16 inches of rain and a dangerous storm surge. This will effect the 700,000 plus residents of the Cancun/Cozumel area. Rina is still headed west slowly but looks like she is ready to make a course adjustment to the northwest.

What happens after she impacts the Yucatan is not yet clear. The NHC has now rounded out their forecast track a bit and guides Rina into the Florida Straights on Sunday. The 18z HWRF model has now joined the GFS in the solution that the incoming trough turns Rina back to the south. While the Navy and and the Canadian model still dissipate Rina over the Yucatan. 

The GFDL is still sticking with a solution that brings Rina to south Florida as a Cat 1 hurricane. If Rina is somehow able to maintain hurricane strength as she moves into the Gulf, this scenario could play out. Maybe not as far north up the Florida Peninsula as the model shows, but maybe a Key West Scenario.

This is the Hurricane Wilma scenario. The water vapor image below is of Wilma making landfall on Cozumel as a Cat 4 in 2005. She then moved across the Yucatan mainland and turned to the northeast towards Florida. Note the same swath of dry air that exists today for Rina. The big difference is the size and intensity of the hurricane. Wilma was not going to be pushed around by a pesky front. The set up is similar though, and climate history should still play a role in creating a forecast. I'm not saying that Rina is going to explode, but I will never forget how surprised I was when I woke up on the morning of October 19th, 2005, and saw that Wilma went from Cat 1 to Cat 5. Wow.

(Hurricane Wilma Water Vapor, 2005)

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