Hurricane Wilma: Category 1 and strengthening

By: Dr. Jeff Masters , 9:06 PM GMT on October 18, 2005

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Wilma became a hurricane today, tying the record of 12 hurricanes in a season set in 1969. In that year, the last two hurricanes formed after October 30, so 2005 has a decent chance of breaking that record. I expect 2005 will also break the record of 21 total storms, which it now shares with the 1933 hurricane season.

Wilma continues to intensify as a modest pace. The Hurricane Hunters at 4 pm EDT found a central pressure of 970 mb and flight level winds on the weaker (north) side of the hurricane that correspond to winds of 70 - 75 mph at the surface. Stronger winds probably exist elsewhere in the storm, but all indications are that this is a medium strength Category 1 hurricane. An eye has popped in and out of visible satellite imagery this afternoon, but is not yet evident as a warm spot on infrared satellite imagery. Spiral banding and upper-level outflow continue to improve and cover a larger area.

The upper level environment looks excellent but not perfect for intensification, with low wind shear and two good outflow channels, one on the north side, and one on the southwest side. About five knots of wind shear is degrading the outflow pattern and symmetry on the northwest side, and there is still some dry air there for Wilma to contend with. Continued intensification into a Category 3 hurricane by Wednesday looks reasonable, and I'd give it a 40% chance Wilma makes it to Category 4 status by Friday. The GFDL is calling for a 922 mb Category 4 storm by Friday, but this forecast is probably overdone, as the GFDL has been consistently too aggressive with its intensity forecasts for Wilma. By Saturday, Wilma will be far enough north that wind shear from an upper-level trough of low pressure will reduce Wilma's winds by perhaps 20 mph.

Wilma is currently traversing an area of high oceanic heat content (see Figure 1), and this heat content will not significantly fall unless Wilma passes north of the Florida Keys. I would expect an additional 10 mph reduction in Wilma's winds if she makes landfall in Florida north of the Keys, due to the lower heat content of the water. So, expect landfall as a strong Category 2 hurricane if Wilma moves through the Keys, or as a weak Category 2 hurricane further north. Remember that hurricane intensity forecasts are poor, especially 3 - 5 days out, so Wilma's intensity could easily be a full Category higher or lower than this.


Figure 1. Total heat content of the ocean is high over the northwest Caribbean and the southern Gulf of Mexico south of 25 N latitude. Images credit: NOAA/AOML.

Jamaica continues to take a pounding from Wilma, but this should end tomorrow night as Wilma pulls away. The next area of concern is northern Honduras and Nicaragua, where rains of up to 12 inches are expected. However, the portions of these countries that will receive the heaviest rains are relatively flat, so I do not expect massive loss of life from flooding in the mountains.

Next on Wilma's list will be the Cayman Islands, but flooding is generally not life-threatening in that nation. Mexico and Cuba may escape serious damage if Wilma passes through the Yucatan Channel as forecast.


Figures 1. Computer model forecasts for Wilma.

Wilma started moving WNW at 8 mph today, as all the computer models predicted she would. The models are pretty unified, bringing Wilma through the Yucatan Channel or across the western tip of Cuba, and then northeastward into the Florida Keys or the west coast of Florida by the weekend. Two models (the UKMET and GFS) predict that Wilma will pass just south of the Keys. The furthest north model is the Canadian, which picks Sarasota for its landfall. The GFDL, NOGAPS, and the official NHC forecast are in the middle, with a landfall over the Everglades of Southwest Florida. The NOAA jet is scheduled to makes its first flight tonight, and tomorrow morning we should have a better idea of which part of Florida is at most risk. Climatology favors a more southern track, and I expect that we'll see the models converge on a more southerly track through the Keys in the runs we see Wednesday morning.

Elsewhere in the tropics, there is a large area of disturbed weather midway between Africa and the Leeward Islands. Upper level winds are not favorable for development of this area, which is also too close to the Equator. I'll be back with a update in the morning.

Jeff Masters

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60. mybahamas
10:51 PM GMT on October 18, 2005
I am concerned here if storm goes through the Straits ... some of our islands still have damage from Floyd :(
59. keeywester
10:35 PM GMT on October 18, 2005
Here we go again.....we are getting really good at this drill here in Key West. Nobody is going to evacuate this time because they don't have the time or the money with Fantasy Fest coming next week....between gas prices, hotel rooms, and lost wages, these stupid things are expensive to run from. If Wilma were to actually be the one to really clober us this season, she would have plenty of victims. We are getting really good at doing the Hurricane dance ......the shutters will go up in record time.

That's all from Key West......time to go visit the Grotto once again.
58. CrazyC83
10:25 PM GMT on October 18, 2005
Yeah, if this is bad, only God knows what Fred will be like in 2009, especially considering that would more likely be an August or early September storm! (BTW, Frederic was the original name in that sequence in 1979, then Fabian in 1985, 1991, 1997 and 2003 and Fred in 2009).
Member Since: September 19, 2005 Posts: 0 Comments: 142
57. MIAWX
10:25 PM GMT on October 18, 2005
I've heard some talk in Miami of people saying that since it's coming in from the gulf, our affect will be minimal. NOT THE CASE. For one, it could be a Cat2 or maybe 3 at landfall and the forward speed will increase significantly, allowing for hurricane force winds to sweep easily across the peninsula (especially if the landfall is where it is projected to be as of the latest advisory. the everglades is nothing but warm water right now.) So Miami really needs to be concerned!
56. sngalla
10:24 PM GMT on October 18, 2005
Oops, SWLA, I mean.
Member Since: February 18, 2003 Posts: 57 Comments: 5363
55. Skyepony (Mod)
10:24 PM GMT on October 18, 2005
Jeff's got a new blog up. She's strenthin quick!
Member Since: August 10, 2005 Posts: 175 Comments: 38201
54. sngalla
10:23 PM GMT on October 18, 2005
Lol SWFL.
Member Since: February 18, 2003 Posts: 57 Comments: 5363
53. SWLAStormFanatic
10:23 PM GMT on October 18, 2005
When Wilma explodes, I just hope she doesn't go "Bam Bam" and leave lots of "Rubble". Sorry, I couldn't resist.
52. primez
10:18 PM GMT on October 18, 2005
I think Wilma is containig her anger towards Fred. Sooner or later, she's going to explode.

Just so everyone knows, Fred will be used in 2009 as a replacement for Fabian.
Member Since: September 18, 2005 Posts: 0 Comments: 195
51. ralphfurley
10:15 PM GMT on October 18, 2005
Max Mayfield was with Bryan Norcross(CBS/MIAMI)...both seemed very concerned about the Keys. Talk of having enough time to prepare.

Norcross stated that "news isnt good: for south FL;dont be fooled because storm isnt coming in from the Atlantic.

ABC and NBC have backup weather crews. I do believe they will abdanon the "poo pooing/it could hit Mexico mode" to the "we go live to home depot/publix mode"

Stay classy.FURLEY OUT!
Member Since: September 18, 2005 Posts: 0 Comments: 117
50. primez
10:14 PM GMT on October 18, 2005
Wow. Wilma is beginning to remind me a lot of Rita. 7 mb in just a little over an hour... Wow.
Member Since: September 18, 2005 Posts: 0 Comments: 195
49. rwdobson
10:14 PM GMT on October 18, 2005
Crazy, that's a pretty hard right turn you have there. i guess if wilma follows that path she could hit cat 4 or 5.

i think if Wilma gets caught up in the trough and races NE, which models are predicting, this will limit the strength when/if it hits Fla.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
48. BwanaDogSWFLA
10:14 PM GMT on October 18, 2005
Bwana,

Live in Bradenton, about 1/4 mile from Sarasota Bay. I'm not really concerned at this point...more just watching and waiting.


Yeah, you seem to be good to go at this point. I am in Cape Coral. So we're not out of the woods. Charley sucked. Plywood and kit restock tomorrow. People aren't freaking out yet, but tomorrow is a different story.
47. Buhdog
10:14 PM GMT on October 18, 2005
I agree lefty...if she makes it as far north as me(cape coral) she will be between 110- 120-- shear and water temps should knock her down a tad...however---I do not know what to think with some of her early behavoir problems---(pressure to wind) ( sw jog ) (quck nw jump) she seems to want to be one step ahead of our analysis. That being said---the models are in VERY good agreement. Chazz is a good example of how timing will be the key to where she goes If train "a" goes one way at 25 mph and train "b" goes in another direction at 20 mph when will A meet B? I was never good at those questions!
Member Since: July 30, 2005 Posts: 1 Comments: 960
46. leftyy420
10:13 PM GMT on October 18, 2005
wannabe thats on you. i have not said or done anything to you sicne i started my own blog. ur moe than welcome to pop in a add ur knowledge oir thoughts. its open to anyone all i ask is we keep it positive

lefty's blog
Member Since: August 24, 2005 Posts: 35 Comments: 1987
45. matilda101
10:12 PM GMT on October 18, 2005
Because this is such a large cirulation field it will a longer time to spin up. In small hurricane can spin up faster and spin down just as fast. In Wilma's case because she is going to be unsualy large it will take quite some time to spin down later on. I read somewhere that this reminds them of a west Pacific typhoon.
Member Since: August 28, 2005 Posts: 0 Comments: 301
44. weatherwannabe
10:11 PM GMT on October 18, 2005
hey lefty lets be buddies - bury the hatchet you know
43. weatherwannabe
10:09 PM GMT on October 18, 2005
2 hours, 7mb. That is some rapid intensification.

Lefty - OK you meant US landfall, that seems reasonable.

42. leftyy420
10:08 PM GMT on October 18, 2005
quick not. the temp diff inside and outside the eye is only 3 degrees c. so when that increases u will see ehr winds really pick up
Member Since: August 24, 2005 Posts: 35 Comments: 1987
41. SWFLdrob
10:08 PM GMT on October 18, 2005
Bwana,

Live in Bradenton, about 1/4 mile from Sarasota Bay. I'm not really concerned at this point...more just watching and waiting.
40. weatherwannabe
10:08 PM GMT on October 18, 2005
OLD

000
URNT12 KNHC 182009
VORTEX DATA MESSAGE
A. 18/19:54:00Z
B. 16 deg 36 min N
081 deg 25 min W
C. 850 mb 1169 m
D. 55 kt
E. 335 deg 020 nm
F. 080 deg 075 kt
G. 348 deg 010 nm
H. 970 mb
I. 16 C/ 1526 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. RAGGED
M. C10
N. 12345/ 8
O. 0.02 / 2 nm
P. AF302 0524A WILMA OB 06
MAX FL WIND 75 KT N QUAD 19:50:40 Z
VERY SMALL WIND CENTER

NEW

URNT12 KNHC 182158
VORTEX DATA MESSAGE
A. 18/21:42:20Z
B. 16 deg 36 min N
081 deg 32 min W
C. 850 mb 1112 m
D. 55 kt
E. 34 deg 051 nm
F. 111 deg 082 kt
G. 024 deg 009 nm
H. 963 mb
I. 17 C/ 1524 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. CLOSED
M. C7
N. 12345/ 8
O. 0.02 / 1 nm
P. AF302 0524A WILMA OB 13
MAX FL WIND 82 KT NE QUAD 21:39:30 Z
39. leftyy420
10:07 PM GMT on October 18, 2005
wannabe, i am talking about florida penninsula landfall. cat3 115mph.


anyone want to stop by my blog tons of info and gopod links stop by

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
38. CrazyC83
10:06 PM GMT on October 18, 2005
82 knots and 963 mb? That would be a borderline Cat 1/2 storm (95 mph), although with a pressure more typical of a 110 mph storm...
Member Since: September 19, 2005 Posts: 0 Comments: 142
37. weatherwannabe
10:06 PM GMT on October 18, 2005
pressure dropped 7mb from the last vortex?

is that possible?
36. matilda101
10:05 PM GMT on October 18, 2005
963 wow!
In normal season this would be quite a feat, but in this season we've seen it so many times. A cat 4 is very possible!
Member Since: August 28, 2005 Posts: 0 Comments: 301
35. CrazyC83
10:05 PM GMT on October 18, 2005
First landfall: 160mph - Cat 5 (Cuba)
Closest approach to FL: 135 mph - Cat 4 (about 60 miles SE of Miami)
Second landfall: 135 mph - Cat 4 (NC Outer Banks)
Final landfall: 115 mph - Cat 3 (Delaware Bay area)
Member Since: September 19, 2005 Posts: 0 Comments: 142
34. BwanaDogSWFLA
10:03 PM GMT on October 18, 2005
SWFLdrob:

I can't answer your question, but where are you in SWFLA? I am too, and I am very nervous about this one.
33. matilda101
10:02 PM GMT on October 18, 2005
The very latest sat shows a the first pic of a small eye.
Member Since: August 28, 2005 Posts: 0 Comments: 301
32. leftyy420
10:02 PM GMT on October 18, 2005
URNT12 KNHC 182158
VORTEX DATA MESSAGE
A. 18/21:42:20Z
B. 16 deg 36 min N
081 deg 32 min W
C. 850 mb 1112 m
D. 55 kt
E. 34 deg 051 nm
F. 111 deg 082 kt
G. 024 deg 009 nm
H. 963 mb
I. 17 C/ 1524 m
J. 20 C/ 1526 m
K. 20 C/ NA
L. CLOSED
M. C7
N. 12345/ 8
O. 0.02 / 1 nm
P. AF302 0524A WILMA OB 13
MAX FL WIND 82 KT NE QUAD 21:39:30 Z

Member Since: August 24, 2005 Posts: 35 Comments: 1987
31. SWFLdrob
10:01 PM GMT on October 18, 2005
Just stumbled upon this blog. Wondering if anyone has taken into account that it seems like most of the storms that have made US landfall this year has done so slightly to the right of the NHC Forecast track...even the tracks made just prior to landfall. Understanding there is always margin of error, no matter how close to landfall...seems like the models or NHC have been pretty close, but always just left of the final landfall. Anyone else notice this? And is this something to consider when thinking about Wilma? (Seems like it's predicted to take a pretty hard right turn already.)
30. weatherwannabe
10:00 PM GMT on October 18, 2005
lefty you are way off, at first landfall it will be cat 4.

29. weatherwannabe
9:59 PM GMT on October 18, 2005
windnwaves maybe you should think before you post?
28. leftyy420
9:59 PM GMT on October 18, 2005
cat3 115mph at landfall
Member Since: August 24, 2005 Posts: 35 Comments: 1987
27. sweeper
9:58 PM GMT on October 18, 2005
I'm headed to Orlando tomorrow for a national conference.
Scheduled to leave on Sunday am?

How's it look? Too early to tell?
Member Since: September 21, 2005 Posts: 0 Comments: 6
26. caneman
9:58 PM GMT on October 18, 2005
Anyone with another prediction on windspeed at landfall?
Member Since: May 27, 2003 Posts: 14 Comments: 100
25. BwanaDogSWFLA
9:55 PM GMT on October 18, 2005
If Wilma is a US landfalling hurricane, it's probably going to be retired...

I hope they don't. I am right in the bullseye, so if it does hit, I think the chances of another Wilma hitting the same place in 6,12,18 years or whatever their cycle is, would be low. But then again, I think I am going to win the Florida Lottery some day too, and I don't even play. :)
24. weatherwannabe
9:54 PM GMT on October 18, 2005
don't even stary with me. i will be monitoring your posts, and if you slip up with any of that "i'm a hardworking barrister bully!" i will mock you the likes of which the blogosphere has never seen. you have been condemned, did you know that?

OK - I will watch it.
23. CrazyC83
9:54 PM GMT on October 18, 2005
This is my gut instinct based on the prevailing conditions - I'm predicting that the ridges will move east to open up the eastern route (which keeps most of Florida clear of the worst of the storm) but gives central Cuba a catastrophic pounding...

If Wilma is retired, that would be at least the sixth storm to be retired in 2005 (most likely) and who knows what will happen when we go Greek...
Member Since: September 19, 2005 Posts: 0 Comments: 142
22. weatherwannabe
9:52 PM GMT on October 18, 2005
windnwaves good luck with that.
20. rwdobson
9:50 PM GMT on October 18, 2005
crazy, what exactly are you basing this forecast on, anyway?
Member Since: June 12, 2002 Posts: 0 Comments: 1589
19. weatherwannabe
9:48 PM GMT on October 18, 2005
windnwaves , not bad. Of course when you are the boss you can take time off whenever you want, like when a hurricane forms. If you work really hard you might have the same chance someday.

Share you analysis with the blog - let's see what an expert like yourself has to say.
18. mybahamas
9:46 PM GMT on October 18, 2005
Hiya from The Bahamas :)
Things are really not looking good for us and Freeport, Grand Bahama :(
They really took a pound from Frances and Jeanne last year :(

17. primez
9:45 PM GMT on October 18, 2005
If Wilma is a US landfalling hurricane, it's probably going to be retired...
Member Since: September 18, 2005 Posts: 0 Comments: 195
16. caneman
9:42 PM GMT on October 18, 2005
Anyone with another prediction on windspeed at landfall?
Member Since: May 27, 2003 Posts: 14 Comments: 100
15. FLCrackerGirl
9:41 PM GMT on October 18, 2005
Thanks CaymanGal for Update. Stay Safe.
Member Since: August 12, 2004 Posts: 47 Comments: 597
13. 8888888889gg
9:37 PM GMT on October 18, 2005
CrazyC83 3 cat 5 in a row that a little cool i do not think that we had 3 cat 5 in a row in one hurricane year so this is new
12. turtlehurricane
9:36 PM GMT on October 18, 2005
i hav updated my blog with my updated wilma forecast.
Member Since: July 22, 2005 Posts: 227 Comments: 469
11. 8888888889gg
9:35 PM GMT on October 18, 2005
CrazyC83 like that one there 175 mph cat 5 3 in a row i think that we nevere been done be LOL
10. caneman
9:28 PM GMT on October 18, 2005
Maybe the wind shear and cooler SST will take some of the starch out of this thing.
Maybe.
Member Since: May 27, 2003 Posts: 14 Comments: 100

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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