Hurricane Dean--9th strongest hurricane on record

By: Dr. Jeff Masters , 2:46 PM GMT on August 21, 2007

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Hurricane Dean powered ashore in Mexico's Yucatan Peninsula this morning as a Category 5 hurricane with 165 mph winds. The pressure of 906 mb measured by the Hurricane Hunters shortly before landfall at 4:30am EDT makes Dean the ninth strongest hurricane on record in the Atlantic. This is the third lowest pressure at landfall behind the 1935 Labor Day hurricane in the Florida Keys and Hurricane Gilbert of 1988 in Cancun Mexico. Dean is also the first Category 5 hurricane to make landfall in the Atlantic Basin since Andrew of 1992.

Figure 1. Dean at landfall, as seen by the Cancun radar. Image credit: Meteorological Service of Mexico.

Radar images at landfall (Figure 1) show that Dean came ashore just north of Chetumal, Mexico, a city of 130,000 people. Dean's center passed about 15 miles north of the city, and Chetumal missed the strongest Category 5 winds of the storm. The strongest winds from Dean were in the right front quadrant on the northern side, since the forward speed of the storm adds to the rotational speed of the winds there. It appears Chetumal was just at the edge of the southern eyewall, and probably experienced sustained winds of Category 3 strength, 115 mph. We don't know, since the weather station stopped reporting data long before the storm arrived. However, a wind analysis done by NOAA's Hurricane Research Division (Figure 2) supports this estimate. The coastal area north of Chetumal where Dean's greatest fury was unleashed has a cruise ship port and a stretch of beach front development, and this region probably suffered near-total destruction.

Figure 2. Dean's winds one hour before landfall. Winds are in knots, multiply by 1.15 to convert to mph. Locations of Chetumal and the Costa Maya Cruise Ship Port are marked. Winds of Category 1 strength (65 kt) are colored yellow, and winds of minimal Category 3 strength (100 knots) are colored pink. Image credit: NOAA/Hurricane Research Division.

Further north, it appears that Cozumel probably got sustained winds near tropical storm force, 39 mph. The weather station there stopped transmitting data before the storm arrived. Cancun's winds topped out at 29 mph, gusting to 54 mph. To the south, Belize City has had top winds of 23 mph, gusting to 35 mph, so far this morning. On the western side of the Yucatan Peninsula, the winds are starting to rise at Campeche. Dean's center will pass south of Campeche, and bring tropical storm or Category 1 hurricane-force winds to the city.

Dean is powerful enough to survive the crossing of the Yucatan as a hurricane, and I expect it will be a Category 2 hurricane with 100 mph winds when it pops out into the Gulf of Mexico later today. Hurricane Janet of 1955, which hit near Chetumal as a Category 5 storm with 170 mph winds, weakened to a Category 2 storm with 105 mph winds when it popped out into the Gulf of Mexico south of Campeche. Janet was moving at about the same speed Dean is, so I expect Dean will behave similarly. Once out over the warm waters of the Gulf of Mexico, Dean has time to intensify by perhaps 15 mph before it makes a second landfall near Poza Rica. Dean will finally dissipate in the mountains about 100 miles north of Mexico City, and could bring heavy rains to the Mexican capital. No hurricane has ever survived the crossing from the Gulf of Mexico to the Pacific over the wide, mountainous portion of Mexico.

Links to follow today:
Campeche, Mexico observations.
Radar from Cancun, Mexico.
Belize City observations.
Morphed microwave animation.

Disturbance 92L
An area of disturbed weather associated with a tropical wave, 92L, is a few hundred miles north of Puerto Rico. This disturbance is less organized than yesterday, despite some rather favorable upper-level winds. There is some dry air to the north that may be interfering with organization, and there is probably not enough turning motion available from this tropical wave to get 92L spinning. I don't expect significant development today given its current state of disorganization, but 92L deserves close scrutiny over the next few days. None of the reliable computer models develop the system.

My live appearance tonight on Internet Partnership Radio
I'll be the guest tonight on the Internet Partnership Radio ( Tonight's show is called "Center of Circulation", and consists of global severe, winter, and tropical weather news/topics with up to the minute advisories, watches and warnings, safety & preparedness info, and periodic special guests. The host is Charlie Wilson. I hope you can listen in!

I may do a short update this afternoon, and the next full update will be Wednesday morning around 10am EDT.

Jeff Masters

Dean 2007 (nickmini)
A roof dumped atop another house
Dean 2007

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718. NeverPanic
12:19 AM GMT on August 22, 2007
Havent been on this blog for a day or so and from the sound of things you would think Dean is drawing his last breath.
He's still out there and going to cause more trouble to those in his path.
Not trying to be a a$%h*le but instead of arguing about who is better or done more or seen more then the other......FOCUS on whats in front of you or others. Dean is still a threat to some and I'm sure some are here to do what you do best. Warn those in the path.

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715. presslord
12:17 AM GMT on August 22, 2007
yo nailed's the hand-rubbing "Oh goodie!!!! I'm gonna make a killin!!!!" anticipation I find's more a matter of minset , I suppose
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714. bswigg
12:13 AM GMT on August 22, 2007
Thank you SW...I only look at those...will start learning to read the other features to the models...just interested since I live a mile from the water in south florida delray beach...
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713. StormJunkie
12:12 AM GMT on August 22, 2007
Evening press ☺

I'm up to play devils advocate....

So, what is the deal with funeral parlors? And how about psychiatrists? Or, how about disaster relief folks, you know the ones that clean up after floods and fires?

Just saying, just because your business profits from tropical systems does not make it inherently bad. Now, if you are praying and wishing for disaster so you can make a buck, that is a little different.
Member Since: August 17, 2005 Posts: 26 Comments: 16970
710. ovrrxn
12:05 AM GMT on August 22, 2007
I must agree with eyewall. This is my first time on this site, and I have learned that I "troll" for entertainment purposes only. The only scientific data provided is regurgitated from NHC, and there is a competition on who can copy and paste this information first into this blog. Not very useful. So, since I do need to know this information based on my demographic location, I will visit more reliable sites and steer clear from the amateur speculators.
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708. Skyepony (Mod)
12:11 AM GMT on August 22, 2007
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 21st day of the month at 23:50Z
Aircraft: Air Force Aircraft (Last digit of aircraft registration number is 306)
Storm Number: 04
Storm Name: Dean (in the North Atlantic basin)
Mission Number: 16
Observation Number: 03

Mandatory Data...

Observation Time: Tuesday, 23:48Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 25.2N 89.8W
Map this location:
Location: 331 miles (532 km) to the S (177) from New Orleans, LA, USA.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 7,320 meters
Flight Level Wind: From 110 at 35 knots (From the ESE at ~ 40.2 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: -16C
Flight Level Dew Point: -46C
Weather (within 30 nautical miles): Broken clouds (5/8 to 7/8 cloud coverage)
400 mb Surface Altitude: 7,630 geopotential meters

Remarks: SWS 026KTS
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704. presslord
12:06 AM GMT on August 22, 2007
I'm a real estate developer...hardly a profession generally held in high esteem....but anybody who sees these kind of natural disasters as "Business opportunities' is disgraceful...
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702. WPBHurricane05
8:06 PM EDT on August 21, 2007
EWR I've been through the same storms as you, except for Andrew and Katrina where I got the outer rain bands.
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701. Inyo
12:02 AM GMT on August 22, 2007
Dean's eye is reemerging!

bad news for Mexico.

also look what that GDFL run does to the storm after it crosses mexico... strengthens it to a Cat 3 in the Gulf of California... that seems pretty unfeasable but imagine if it happened...

it might put out the fires in California to say the least.
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699. Bishop99
12:03 AM GMT on August 22, 2007
Posted By: EyeWallReplacement at 11:50 PM GMT on August 21, 2007.
DoverDan, you are GOD !!!

Nailed it right on the head.

I, by the way do have a meteorology degree, have been living in South FL for 19 years, and endured DIRECT hits from Andrew, Iris (1995), Frances, Jeanne, Wilma, and Katrina, and I am a coastal engineer.

Not bad for a smart dork...

Did you mean Irene (1999)?
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698. WPBHurricane05
8:02 PM EDT on August 21, 2007
Im not in the disaster field, just the building field. Huge building field.. lol... cant say what.. im under the wrong handle.. lol...anyway, thank goodness for jeanne and frances which lifted us up. ok im done.. lol

Idiot. If you know the damage people went through in both of those storms, you wouldnt be saying that. 3,000 people in Haiti alone died in Jeanne.
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697. ProfGoose
12:03 AM GMT on August 22, 2007
Here's Chuck Watson's model of Cantarell and KMZ damage/infra and his projection:

Watson Dean

NHC has dropped their intensity more in line with our estimates. I'm sticking with the earlier damage forecast - Southwestern about 10 days, Northwestern (Cantarell etc) 15 to 18 days, unless something unlucky happens like a critical component failure. So our total shut in forecast from this event is around 30 million BBL, which was at the low end of my earlier model. The storm decayed more than the NHC estimates.

So, if you all have any insights or hear any reports, here's our thread at The Oil Drum to report them: Link to TOD discussion

Thanks for all of your help and answers on our questions. You guys were great.
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696. CaptnDan142
11:56 PM GMT on August 21, 2007
I'm still not a wannabe!

I agree StormW.

I consider you a "be", not wanna-be. With a healthy dose of 'been there, done that' thrown in.

I appreciate your synopsis... um, OK, what's the plural of that word?? Well, I appreciate it anyway. lol
Member Since: August 21, 2007 Posts: 0 Comments: 856
695. StormJunkie
12:00 AM GMT on August 22, 2007
Posted By: EyeWallReplacement at 11:50 PM GMT on August 21, 2007. (hide)
DoverDan, you are GOD !!!

Nailed it right on the head.

I, by the way do have a meteorology degree,

LOL :~)

As I stated earlier. There are two types of mets...

The ones that are jealous that us "ordinary joe's" can learn so much about the weather for free because OUR tax dollars pay for it and the ones that are happy to have more folks interested and learning in the field!
Member Since: August 17, 2005 Posts: 26 Comments: 16970
693. bswigg
11:59 PM GMT on August 21, 2007
I am seeing about 90hrs out...that is a fish storm just curious that all the models have it...
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692. StormJunkie
11:55 PM GMT on August 21, 2007
So Dover, do you trust the TWC prior to taking a trip to the Bahamas? Do you trust your 6:00 news guy? Hell, many of them are "broadcast mets"...They are all trying to sell you something. Ever seen all the vacation commercials on TWC?

With the wealth of field specific information available in this day and age, our educational institutions are outdated. Matter of fact, most folks can not find work in the field they are degreed in.
Member Since: August 17, 2005 Posts: 26 Comments: 16970
687. Bobbyweather
7:53 PM EDT on August 21, 2007
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686. KRL
11:49 PM GMT on August 21, 2007
Posted By: IAmRooot at 11:31 PM GMT on August 21, 2007. paleotempestology or paleohurricanes for a geological history. but as far as ancient civilizations documenting hurricanes, i remember learning about a civilization that would record weather events on the pottery they made. since i've slept ALOT since then, the time and place escapes me. i'll see if i can find it.

Thanks IAmRoot, found some interesting reading already searching those terms. Hadn't heard of those before.

From what I've found so far, the Mayans did keep records of the Hurricanes and also scientists are developing a way to study oxygen isotopes corrolated in geological spots where storm surges could have occured and indicated a major inflow of ocean water.
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684. katadman
11:52 PM GMT on August 21, 2007
Hey guys, I'm a little confused. The NHC advisory gave the coordinates of Dean as of &;00 CDT. I am in CDT and it's not &;00 yet. Explanations?
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683. bswigg
11:54 PM GMT on August 21, 2007
SW 40N 40W on the CMC and I believe most of the other models form somthing there 3 others I looked at...
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681. StormJunkie
11:45 PM GMT on August 21, 2007
EWR, you can go to many blogs and pick out mistakes and foolish statements, but when you generalize it shows your true colors...

The other side of your view is the majority and what folks come here to read. Myself included. Examples follow....

Posted By: Weather456 at 11:22 PM GMT on August 21, 2007.

Most active weather in the Caribbean is over the southwest portion where strong upper winds assoicated with the complex upper pattern over the Caribbean today and low level lift from the Colobian low and the tropical wave is enhancing showers and thunderstorms from 15N to 5N between 65W and 90W ( activity near 90W is also enhanced by the EPAC monsoon trough/ITCZ). This mess of showers is expected to drop between 20-40 mm of rain over portions of NW South America and Lower central America and thats according to TRMM rain accumulations imagery.

The lesser antilles with relatively drier but could see chances of passing showers. Trades continue to deviate from the norm due to the tropical wave and Dean's circulation but that should change as both features moves westward away from the Caribbean.

by W456

More good stuff here

Posted By: KShurricane at 5:23 PM GMT on August 21, 2007.
Cool - so being the 9th lowest pressure hurricane doesn't necessarily = being the 9th strongest (windiest) hurricane?

Official hurricane intensity or strength is measured by minimum central pressure ONLY. Winds have nothing to do with it. The SS scale only uses windspeed because the average person watching hurricane updates on the news can't relate to pressure changes. So, if you have hurricane A with 140 mph winds and 912 mb pressure and hurricane B had 170 mph winds and 927 mb pressure, hurricane A would be officially the more intense storm.

Posted By: atmoaggie at 4:21 PM GMT on August 21, 2007.
CIMMS is odd, though when you look at the shear tendency. It also displays shear, but on that map, there is greater than 30 knots shear(yellow colors and warmer) from 10N to 45N at about 25W. This map usually shows more shear than the 'shear' map. They are both good products, just bugs me that they do not show the same shear. Also, shear is on an increasing trend for the same area (white lines).

Now, that was just a quick glance of a little bit of the info that the folks here bring to the table. What I would really like to know is how brilliant you can be if you are wasting your time here?

I would also be interested in knowing what your knowledge of weather is?
Member Since: August 17, 2005 Posts: 26 Comments: 16970
680. Swells22
11:50 PM GMT on August 21, 2007
"Storm dorks," that was a funny think to say. :)
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678. WPBHurricane05
7:51 PM EDT on August 21, 2007
DoverDan, you are GOD !!!

Nailed it right on the head.

I, by the way do have a meteorology degree, have been living in South FL for 19 years, and endured DIRECT hits from Andrew, Iris (1995), Frances, Jeanne, Wilma, and Katrina, and I am a coastal engineer.

Not bad for a smart dork...

Iris didn't come near Florida.
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677. bswigg
11:48 PM GMT on August 21, 2007
Hey SW looks like most of the models have something forming very north in the ATL can that be 92L because the BAMD and LBAR have it curving up north...most of the models have somehing forming at about the 90hr or it 92L or another wave??
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11:46 PM GMT on August 21, 2007
Talking bout CAT 6's.

They wont go over a CAT 5 because it will destroy everything anyway.
Well, look at mexico. Yeah, CAT 6 would be very rare,


what if Dean went into GOM, a CAT 6 may have happened.
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673. Bishop99
11:44 PM GMT on August 21, 2007
Posted By: HurricaneMyles at 11:43 PM GMT on August 21, 2007.
wederwatcher555...Using 2006 as the only year in comparision isn't correct. 2006 probably isn't even a good analog year. El Nino squashed the end of the season last year and this year it's going to be neutral or La Nina. I wouldn't expect this season to just die out after Sept like last year did.

True, with the possible development of a weak La Nina it is possible that there could be a little more activity in Oct. and Nov. than normal.
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672. LandLubbers
11:40 PM GMT on August 21, 2007
There is a new NHC bulletin on Dean. They are updating the heading:


Exactly WNW would be a heading of 292.5

My eyeball measurement was giving me 300, which would also be called "WNW" -- within reasonable approximation.

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671. KRL
11:43 PM GMT on August 21, 2007
Posted By: NOTSTLN at 11:29 PM GMT on August 21, 2007.
(con'd) Several strong and vigorous waves are exiting the African coast with good convection and low pressure. Several computer models are hinting at development around the 150 hr mark.

Otherwise, Dean is the most exciting thing happening so far this season...

Have you ever experienced a major hurricane?

The last thing a Cat 5 is "Exciting" for the poor souls in its path.

Man, show at least a little compassion and respect for the unfortunate during the storm.


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11:41 PM GMT on August 21, 2007
Preseason forcasts at least get the emergency managers spun up, after 05 the've been hyper-sensitve, local, State and Federal. I'd rather they be ready than not.
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668. Stoopid1
11:42 PM GMT on August 21, 2007
DOOM would be a funny name...

Lol, I could see it now; Hurricane Doom makes landfall in Florida as the first Category 6 storm in history. A BFG(Big freaking gust) of 291 mph was recorded and all hell literally broke loose...
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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