Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 8:29 PM GMT on September 22, 2005
Reconnaissance flights this afternoon indicate that the weakening phase Rita went through has ceased. Her central presure has held steady between 913 and 915 mb between noon and 4 pm, and the surface winds are steady at about 145 - 150 mph. Rita is a strong Category 4 hurricane. She appears to be going through a collapse of the inner eyewall, which the hurricane hunters have noted has a large gap in it. It may take 12 - 24 hours for Rita to rebuild her eyewall. During that time, some fluctuations in strength may occur, but weakening is most likely. This would occur as a result of 10 knots of shear on her south side from an upper-level high pressure system, and from passage over ocean waters with less heat content. By landfall time on Saturday afternoon, it is expected that Rita will be a Category 3 or 4 hurricane, but still carry to the coast a storm surge characteristic of a much stronger hurricane. A Category 4 or 5 level storm surge is likely along a 60 - 80 miles stretch of coast to the right of where the storm makes landfall on Saturday. Storm surge heights will peak at 15 - 20 feet in some bays, and bring the ocean inland up to 50 miles from the coast. Large sections of I-10 between Houston and Beaumont could be inundated, and the flood waters may reach the cities of Beaumont, Orange, and Lake Charles.
Figure 1. Expected inland penetration of a Category 5 level hurricane storm surge. Only areas along and to the right of Rita's landfall point may get a Category 5 storm surge. If Rita makes landfall east of Galveston, Houston and Galveston will not see the storm surge flooding shown here.
Current buoy measurements
NOAA buoy 42001 in Rita's western eyewall measured sustained winds of 90 mph, gusting to 112 mph, and 34 foot waves at 2:50 pm CDT. A time series plot of the wind and pressure from buoy 42001 is worth checking out.
Where will Rita go?
The 12Z (8am EDT) computer models in general show a shift a bit more to the east, making a landfall near the Texas/Louisiana border more likely. Keep in mind that the average error in landfall location for a 48 hour forecast is 125 miles, which means the landfall point could be anywhere from the Central Texas coast near Matagorda to the central Louisiana coast near New Iberia.
The models runs are now pretty much agreed that steering currents will weaken and Rita will stall and drift westward or southwestward once it moves inland. This will result in severe flooding problems for wherever Rita stalls, as 10 - 30 inches of rain could fall in the affected region. As is usually the case when steering currents get weak, the model forecasts of Rita's motion are highly unreliable. Rita may stall over the notheast Texas, or western or central Louisiana. Oklahoma and Arkansas are looking less likely. It's too early to tell with much reliability. It may not be until next Wednesday when the remnants of Rita finally are gone.
Elsewhere in the tropics
Tropical Storm Philippe is a minimal tropical storm heading out to sea, and is not a threat to any land areas. An area of disturbed weather off of the coast of Honduras has diminished and is no longer a threat. Development off of the coast of Africa is possible beginning on Sunday.
A new blog called TheDiscussionBlog has been set up by tornadoty to serve as an alternate discussion forum for those who want to pose questions. I will read it and respond to questions there if I get the time, which hasn't been too plentiful of late, unfortunately.
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