WunderBlog Archive » Category 6™

Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.

Rita's eyewall collapsing soon

By: Dr. Jeff Masters, 3:44 PM GMT on September 22, 2005

We continue to live history as this incredible Hurricane Season of 2005 unfolds more stunning surprises. Rita has peaked in intensity as the third strongest hurricane of all time, with a pressure of 897 mb and 175 mph winds. She is on the decline now, as the 11am hurricane hunter mission found a pressure of 913 mb, and increase of 5 mb in just 3 hours. The hurricane hunters also found concentric eyewalls of 17 and 55 nautical miles in diameter. All these signs indicate that Rita will continue to weaken today as her inner eyewall collapses and an eyewall replacement cycle begins. Rita is about to leave the vicinity of a warm eddy of Gulf water called the Loop Current that has been aiding her intensification. In addition, 10 knots of shear has developed on her south side, thanks to the fact that the upper-level high pressure system that was providing such excellent outflow for Rita has now shifted to the southeast of the storm. All these signs point to a substantial weakening trend for Rita that will continue through Friday and probably reduce her to a Category 4 hurricane. The GFDL forecast model and NHC predict that this weakening trend will continue until landfall Saturday, when Rita will be a Category 3 hurricane. Lower heat content water and continued shear are expected to cause this weakening.

While this is cause for some relief, Rita, like Katrina did, will still bring 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. Wind damage will be severe, and Houston can expect a hazardous rain of glass from its high rise building like was experienced during Hurricane Alica in 1983. If the eye passes just west of Galveston Bay, the storm surge will push 1 - 3 of water into some of Houston's eastern suburbs, such as Deer Park.

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 measured sustained winds of 58 mph, gusting to 78 mph, and 34 foot waves at 10am CDT. At the time, the buoy was located 75 miles WNW of Rita. This evening at 5pm CDT, Rita should make a very close pass by this buoy. I expect waves of 50 - 70 feet will impact the buoy, and huge swells from Rita are already starting to pound the Gulf Coast. A time series plot of the wind and pressure from buoy 42001 is worth checking out.

Where will Rita go?
The computer models made a modest shift eastwards this morning, calling for a landfall between Galveston and the Texas/Louisiana border. The Hurricane Center shifted their landfall point as well, and now go with the model consensus. The models have been flip-flopping frequently, and it is not unreasonable to suppose that they will shift the landfall point 50 or so miles further west again this tonight. However, a landfall within 100 miles of Galveston seems to be the the best call. Landfall will still occur sometime Saturday, but this may be afternoon instead of morning, as the storm is moving slower than before.

Most of the models now indicate that steering currents will weaken and Rita will stall and sit in place for several days 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 current get weak, the model forecasts of Rita's motion are highly unreliable. Rita may stall over the Dallas area, or central Louisiana, or Oklahoma or Arkansas. It's too early to tell. Finally, on Tuesday, Rita's remnants are forecast to lift out to the north.

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 is being sheared by the strong upper-level winds flowing south from Hurricane Rita. If this disturbed area still exists on Sunday, it has some potential for development. Development off of the coast of Africa is also possible beginning on Sunday.

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.

Reader Comments

she's blowing up again
Does anyone know if they have shelters in Houston. I know people were in the astrodome from Katrina (and now moved) out but are there any schools and the like for houston people who can't get out of town? I can't seem to find any information on this.
valence micorwave imagery is like radar absicaly. it messaures the microwaves given off by the water in the storm. its a uselfull tool for seeing inside of the storm when she is out of radar range. ir only shows the cloud temps, nothing about the inside of the storm. alos microwave data is recorded in the 37-89 mhz range as it does not get defelected by the ice particles in the upper cloud regions of the storm
And is anyone getting pissed off looking at the parking lots that TX is calling a highway right now?

As much as everyone complained about the slow (and it was) response of the NO leadership, at least they had a plan in place to get everyone out.

Why are they not opening up at lesat a few of the S bound lanes to help people evacuate? And how long before before just start saying F-it and either go home, or just drive on the wrong side of the road?

leftyy, I'm thinking a strong cat 4 at landfall, you agree?
wbp05 - All this obsession with NO is not with a direct hit with the weakened leveys. NO does not need a direct hit to have the same flooding problem that they had during Katrina. I heard that if they get over 6 inches of rain that the leveys could be in danger. With the current track I certainly see where this is possible. Also with the storm making landfall to the west, it puts it on the eastern side of the storm which could subject it to heavy rains along with a storm surge. Thats why so many people are obsessed with NO.
Do you all think it will hit closer to Freeport/Galveston, or around Port Arthur/TX LA border? Probably just guessing at this point, but I'm curious as to what people think.
Bouy 42001

Current Weather/Wave Observations
Updated: 2:50 PM CDT on September 22, 2005
Air Temperature 79 F / 26 C
Humidity 99
Wind direction (W Dir) North (345 - 354 Degrees)
Wind Speed (W Spd) 77.8 kts (89.5 mph / 144.0 km/h)
Dominant Wave Period (DWP) 14 sec
Dominant Wave Height (DWH) 34.45 ft / 10.50 m
Dominant Wave Range (DWR) exactly 34.4 ft / exactly 10.5 m
Wind Wave Period (WWP) 14 sec
Wind Wave Height (WWH) 34.45 ft / 10.50 m
Wind Wave Range (WWR) 33.63 - 35.27 ft / 10.25 - 10.75 m
Atmospheric Pressure (AP) 28.44 in / 963 hPa
Pressure Tendency (PT) -0.70 in / -23.7 hPa
Steady or increasing, then decreasing; or decreasing, then decreasing more rapidly
weatherdude65, she will start weakeing rapidly about this within 12 hours of landfall - there is insufficient heat potential in the coastal waters for a stron cat 4 -
yeah weatherdude. o made a forcast on hookedontropics blog of 140-150 at landfall
18z pkg looks very similar to 12z, but an even greater loss of direction after landfall. Looks like NHC will inch a bit closer to the border, but will stay in TX. IMO, Rita will track to the weakness between the two ridge centers(Cent LA) while regaining strength with a decreasing trend prior to landfall. Wind field will expand however as the eyewall replacement ends. I think she hits Intracoastal City area. If i lived in Galveston or NE TX, i would not bet my or my family's life on that though...
had to post this link for the know it all blog might be something intresting for us here in the Tampa area.
they drove partition piling infront of the levee at 17th. It will leak but it shouldn't break unless this bitch keeps on going nore north.
Lost is all the chatter here and in the media is the fact that New Orleand DID NOT take a direct hit in Katrina.
516. Selu

I've been predicting Port Arthur/Sabine area as a Cat 4 for 4 days now. I still hold that prediction, but I am scared to death that Rita's track may continue to be adjusted eastward, and Louisiana will get the second punch.
water temp at the bouy 22 miles east of Galveston is at 86
518. Selu

Yes, NOLA was on the west side of the eye. I hope everyone here is aware of that.

Still, I live 60 miles north of NOLA, and we had tremendous damage. Katrina was such a hefty storm that you didn't have to be in the eye or on the east side to suffer horrific damage.
leftyy, my prediction on hookeds blog is 145mph
520. wpb05
I am tired of the obsession with Sin city
valence u understand microwave data now?

The energy to sustain a hurricane is not all about Sea Surface Temp. It the temp of the water and depth at which that heat is held. Coast waters are very shallow. This is why cat 5 storms only hit things in the middle of the ocean.

Besides, unless she starts moving faster, the interaction with the land mass is going to knock her down to a 3. Too much sear on the S end of the storm, so the N is where she's getting her power from.

523. Selu

Where do you live? Could the fact that you are located nowhere near "Sin City" be coloring your opinion?

weatherdude65 see the charts I posted earlier showing the heat potential for BLOBBY -
Yes, lefty. And now i understand your fascination with it too :- )

weatherdude65 just click on my name - the charts are posted in my pic section.

here u guys go. this is about 6 houts old but shows the eye wall cycle starting to end. this is a microwave image of inside the storm. should have a new sat pass soon so you can see what she looks like now

Weatherdude, you didnt post the gusts of 97 knots.

Why is it that these eyewall replacment cycles can only been seen by the Microwave?

I used to able to see them just looking at IR or water vapor, but now I wouldn't know one unless you told me!

530. wpb05
location has nothing to do with my opinion, nothing at all...hence the title of the city
weatherdude65 please note the seep blue on the Heat Potential chart that lies about 300 NM off the TX/LA coast. That is not conducive to Cat 4/5.
Thanks weather....was not paying attention to the depth....very shallow
I have been reading this blog for a while... I am from MS, and my area was hit by Katrina at a still strong 3 storm. Our area is devastated, and even more so than NO when it comes to wind damage. (Of course the levees in NO caused flood issues, no denying that) The media hypes everything, and you guys need to remember that. The media will look for any and all reasons to come down on whoever is president, or the local officials if they can. If you really want to know what happened in New Orleans, then you need to keep in mind exactly what is happening in TX. Many people can not leave, or once they leave they turn right back around because they lack money or patience. In the case of NO most of its population is on a fixed income, and money or means of leaving wasn't readily available. Blame doesn't really lie on anyone. Things could have been much better planned, but remember they always can be better! Galveston may have not been out so quickly had they not seen Katrina, and many of their residents have acknowledged that fact. So please, stop with the blame game, its useless.

As far as traffic, people... thats to be expected. In fact, we are along the I59 corridor and expected MORE traffic from NO... which we never saw. And this route has been turned contra several times in the past few years, so plenty of practice. You wont ever be able to plan for the little things, like no gas, car problems, fender benders... each of which throw a kink in the flow.. no matter the perfection of the plan!

And here's a question for you all, anyone notice that the weather channel and such are slow to post anything different from their initial warning areas, no matter the shift of the storm, until the last minute.. when it becomes absolutely necessary? How much of this is scare tactic for the "just in case" and "cover our butts" scenarios?

Just a thought, keep up the interesting posts!
Sorry guys, the woman is home. I guess I have to have some "quality time" with her.

I'll be back later.

some times they are signs of an eye wall replcement in ir imagery but some times in a real intense storm the signs get overshadowed by the deep convection. microwave data is just like radar and u can see the eye wall and any other forming eye walls init. thats its claim to fame,the ability to locate the cenetr of a storm and see the orginisation of the core when they are way out in the open water where we have no radar or recon reports
Hey guys, there is no chance this has a direct hit on galveston? That would go NW of a position south of where she is.. The quesion I have is that good news or bad news..

Galveston is going to be getting beat up on the bay side with nw winds if that happens, giving them a double whammy
That buoy is in for a beating, hopefully it'll give us some good readings before Rita blows it apart. I believe it is only 33 miles to the WNW of the eye at this point.

Buoy: 25.84N 89.66W
Rita: 25.7N 89.2W
538. awnm
tilidarose -
My uneducated guess is Freeport. I just don't see the sharp north shift yet it will take to get to the TX/LA border. The weatherdude on the Houston TV station was talking about the Low over the Great Lakes having great impact on the high over TX/LA. It's movement could allow the high to strengthen again and move Rita west a bit.

Of course, I have no idea what I'm talking about! :)
NHC hasn't updated the landfall forecast?
I have finally found politicians more incompetent than our state "Leaders" How long do they have think about things? We've already had two squalls come through.

"Terrebonne Parish Superintendent Ed Richard said that he has been meeting with the Office of Emergency Preparedness and has not decided whether parish schools will close.

"We are keeping an eye on it, and if it wobbles we will shut the schools down," Richard said.

Richard added that the potential for high tides as a result of the hurricane could also lead to school closures."
on our way to 888.
Anyone have a link to the FSU models? GFDL, GFS etc...
ok guys new vortex out and eye wall cycle is now complete

A. 22/20:20:10Z
B. 25 deg 49 min N
089 deg 22 min W
C. NA mb NA m
D. NA kt
E. NA deg nm
F. 221 deg 111 kt
G. 134 deg 010 nm
H. EXTRAP 913 mb
I. 10 C/ 3658 m
J. 16 C/ 3654 m
K. 11 C/ NA
M. C17
N. 12345/NA
O. 0.02 / 1 nm
P. AF306 WX18A RITA01 OB 05
MAX FL WIND 122 KT NE QUAD 19:19:30 Z

Given the motion today..I could say with certainty its not going south of Galveston..Anyone else agree with this??

New poster here.

As far as storm surge and New Orleans, you're correct that the levees are weakened.

But insofar as rainfall goes, that has little to do with the levee system. The problem with rainfall is that every inch of rain has to be pumped out of the city--true pre or post Katrina-- and the pumps are only operating at less than half capacity.
Link to models.
AWNM....don't worry. Lack of serious knowledge doesn't stop anyone from posting here. At least you admit it. Your opinion is just as valuable as anyone's. Hey...I predicted Katrina's first landfall in Florida to within 1 mile. Based on the Russian name Katrina hittig the most heavily Russian populated part of Florida...North Miami Beach. Even leftyy thought it was a good call at the time......though I've never revealed my reasoning until now.
her motion is nw for 6-8 hrs now. more than a wobble in my opinion at this point. motion is 310-315 degrees. next with this last recon pressure was estimated from flight level to be 913mb. i belive it is likely a lil lower but we will know with the next recon

4:30pm-973mb 23.85n 81.95w
5:56pm-970mb 23.92n 82.18w
6:24pm-969mb 23.93n 82.35w
8:09pm-967mb 24.00n 82.68w
10:04pm-965mb 24.03n 83.07w

11:17am-934mb 24.18n 85.70w
1:02pm-923mb 24.20n 85.93w
1:53pm-920mb 24.28n 86.17w
3:36pm-914mb 24.35n 86.35w
5:16pm-904mb 24.40n 86.53w
7:09pm-898mb 24.52n 86.77w

1:38am-898mb 24.77n 87.57
3:14am-899mb 24.80n 87.77w
5:12am-902mb 24.92n 87.92w
10:49am-913mb 25.30n 88.63w
12:19pm-915mb 25.43n 88.82w
1:45pm-914mb 25.57n 89.02w
3:22pm-914mb 25.73n 89.25w
4:20pm-913mb 25.82n 89.37w
Dr. Masters has a new entry (make sure to read the first comment).
IMO, it'll re-peak in the next 12 hrs at 905 mb, then maintain or slowly weaken to 915 mb at landfall just NE of Galveston.
This is also forecast to turn more northerly before impact.. that is why I say that Galveston will not have an eyewall over it Sat morning
552. awnm
Thanks! I'm not a meteorologist, I don't even play one on TV. But I did stay at a Holiday Inn Express! :)

I'm just going with my gut. I enjoy the varying opinions here and it's been a great education.
553. tessa
Does anyone have a link for a long loop?
Anyone in College Station: I have friends on the road who aren't getting anywhere. Is there a shelter in college station?
new post by dr.masters guys
Continuous Winds TIME
2:50 pm NNW ( 345 deg ) 77.9 kts
2:40 pm NNW ( 344 deg ) 77.3 kts
2:30 pm NNW ( 348 deg ) 74.2 kts
2:20 pm N ( 351 deg ) 69.0 kts
2:10 pm N ( 352 deg ) 64.9 kts
2:00 pm N ( 353 deg ) 63.1 kts

news from the bouy
It seems unlikely to me the eyewall cycle has been completed. First, recon has reported concentric eyewalls all day around 17/45 miles across. An outer eyewall at 45 nm diameter cannot just shrink down to 17 nm in an hour or two. At minimum it would take many hours. Also, the IR satellite pretty clearly shows a double band of cold cloud tops in the CDO, indicative of concentric eyewalls. Third, the latest recon shows only a 6C difference in temp which would also indicate there is an outer eyewall as well. Last, a max flight wind of 122 kts in the 17 nm eyewall is quite low for a 913 mb hurricane with an intense looking core and this also would suggest there is an outer eyewall.
starting western wobble again, looks like, at 20:15.


I know, I know, can't obsess over the wobble, but at this stage in the game each one counts.
559. Remek
B. 25 deg 49 min N
089 deg 22 min W

Might be due to wobble, but that position looks to be slightly W of the last NHC forecast track.
It will be interesting to see if Rita makes it up to 175 mph in this second round of intensification. Of course, I'm referring to the actual wind speed, as opposed to the numbers that are on the NHC site, which have certainly been low with this storm so far, especially last night. If that happens, it will be very bad for whoever is in its path...because at 175 mph, eyewall replacement cycles seem to turn off (still looking for an explanation as to why this is the case--does it have to do with the physics and geometry of a strong stadium effect?), and so with one less possible weakening mechanism, the storm becomes more stable. The dry air entrainment that caused it to weaken this morning (this aside from going over cooler waters) might also not be as much of an issue, as the air ahead of it looks a little more moist than the air ahead of it looked last night.

Of course, if the storm "weakens" by going over slightly cooler water, that will cause it to expand its wind field (that's why I use quotation marks), and New Orleans could have some more trouble potentially, though I think the ideas of levees breaking from too much rain are overblown--as long as the storm surge is low there, it would seem to me that the canals would drain into Lake Pontchatrain, which would drain into the Gulf.
Might be due to wobble, but that position looks to be slightly W of the last NHC forecast track.

I'd say it could be a litle west of the NHC track. It's been moving between WNW to NW (WNWNW?) all day with occasional due west wobbles (I counted 3 since this morning) that lasted about an hour a piece. Not a big development, but certainly better than occasional north wobbles or a full turn to the NW. In the last satellite frame she looked like she may be starting another west jog, but we'll have to wait a half hour for the next 20:45 frame to see. Could be false alarm.

And yes, I realize tracking wobbles is innocuous and petty, but for those of us in, say, Terrebonne, Lafourche, etc. who will soon be almost directly over the storm, these wobbles will keep us on edge until it's a little too west of us to hit us dead on. (if it gets that far...which looks probable)
Eh, just saw the frame, it may have gone a little west but still appears in the same direction, if not slightly more WNW than NW
21:15 west of north
564. db48x
I think they were late getting the contraflow set up, but there are also images of the tail end of the traffic backups entering Houston. Galveston is completely empty (except for the newsies, but you know how that goes,) and a good portion of the people outside of the evacuation zones have evacuated as well.

As for the gas situation, that is unfortunate - that area actually has very few gas stations. However, they're setting up fuel stops at all of the rest stops, and the police have been driving up and down the highway distributing fuel to people who are already out.

http://traffic.houstontranstar.org/ has some good live pictures of empty northbound traffic lanes.
I've been looking a Cameron as ground zero all day but it now looks like it might even be east of there.

See thisLink
. Word is that they're "closed" to everyone EXCEPT stranded motorists.
And also this link too for more BCS shelters...Link
KTRK live stream says a 100 year old building is burning in Galveston, due to an electrical fire.