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Rita a Category 2 hurricane

By: Dr. Jeff Masters, 4:54 PM GMT on September 20, 2005

Rita was upgraded to a hurricane this morning at 9:15 am, and is already a Category 2 hurricane after just four hours. The 4:00 pm EDT hurricane hunter mission found winds at 10,000 feet of 89 knots (102 mph), which corresponds to surface winds of 92 mph. The SFMR instrument on the NOAA hurricane hunter aircraft found surface winds of 100 mph, making Rita a Category 2 hurricane. The central pressure was 973 mb, down 12 mb in the past 9 hours. At this rate of intensification, Rita will be a Category 3 hurricane tomorrow. The Key West radar loop is most impressive the past three hours, showing a rapidly intensifying hurricane with strong spiral banding, and a solid eyewall forming.


Here are the peak wind gusts as of 4:30 pm EDT from Rita:

53 mph at Marathon Airport
60 mph at Key West International Airport
58 mph at Molasses Reef light
48 mph at Long Key light
78 mph at Sombrero Key light
92 mph at Sand Key light (60 mph sustained)
50 mph at Dry Tortugas light
65 mph at Fowey Rocks

The northern eyewall passed just south of the lower Keys and Key West between 1 pm and 3 pm today, sparing the lower Keys the brunt of the storm's fury. The Lower Keys escaped with sustained winds of 40 - 50 mph and gusts to 60 mph. A storm surge of 4 - 6 feet did accompany the arrival of the eyewall. The Florida Highway patrol has reported water and
wave action over the Overseas Highway in a number of areas. The Overseas Highway at 73.5 mile marker is impassable and has been barricaded to all traffic. It looks like Key West's hurricane grotto protected the city again! If Rita had tracked just 50 miles further north and started its intensification cycle 24 hours earlier, much of Key West might have been serioussly damaged with some loss of life.

Rita in the Gulf
As Rita continues on into the Gulf of Mexico tonight, continued strengthening is expected. The shear over her has dropped below 5 knots, and may decrease further. The upper level outflow has improved considerably today, and Rita now has a more circular and symmetric appearance with excellent outflow on all sides. The water under Rita will remain in the 30 - 31C range until Wednesday morning, then cool off to 29 - 30C over the middle of the Gulf of Mexico, where the cooler waters stirred up to the surface by Hurricane Katrina still remain. These cooler waters should keep Rita in the strong Category 2 to strong Category 3 range as she moves across the central Gulf. Once Rita approaches the coast of Texas, the cold water wake of Katrina ends and water temperatures warm up to about 30C, which may allow some intensification. Rita will be a Category 2, 3, or 4 hurricane by landfall in Texas on Saturday. The 8am of the GFS model indicates Rita may be a Category 4 at landfall.


Figure 2.Sea Surface temperatures for Monday, September 19. Note the cooler wake in the center of the Gulf left by Katrina.

Threat to Louisiana fades
Last night, the NOAA jet flew its first mission into Rita, and collected high-density data used to initialize last night's computer model runs. The models are more tightly clustered than before, and now all the models point to a landfall in Texas Saturday, somewhere between Brownsville and Galveston. NHC thinks that their current projected landfall point near Matagorda, TX is more reliable than usual. If we take the average NHC 4-day forecast track error of 200 miles and knock it down by 50 miles or so since we're assuming NHC is correct about their more reliable than usual forecast, this gives a probable landfall point somewhere between Corpus Christi and the Texas/Louisiana border. So, western Louisiana is still at considerable risk, but New Orleans will miss this hurricane.

Hurricane Philippe
Stong westerly winds have started to tear Philippe apart, and he is now a tropical storm. Philippe is not expected to affect any land areas, including Bermuda, as he heads north and then northeast, out to sea.

Wave between Africa and the Antilles
The large low pressure system halfway between Africa and the Antilles islands has been absorbed by Philippe and is no longer a threat. Later in the week, the shear over the central Atlantic is expected to decrease, and we could see another tropical storm form in this region.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.