Hurricane Dean--9th strongest hurricane on record

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

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 (http://www.ipr365.com). 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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

Sign In or Register Sign In or Register

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 168 - 118

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

168. ClearH2OFla
1:00 PM EDT on August 21, 2007
bswigg i think that is possible. Not probable. I did notice the southeast jog towards tampa after it forms.
Member Since: Posts: Comments:
167. bswigg
4:57 PM GMT on August 21, 2007
What do you guys think about the CMC developing 92L once it hits the gulf side?? Looks like a TD on the east then it blows up in the gulf...
Member Since: Posts: Comments:
166. Cregnebaa
4:50 PM GMT on August 21, 2007

My bad, 150mph sustained winds recorded , and gust over 170, high Cat 4. Man and I spent the last 3 years thinking I lived through a Cat 5.

From NHC archive:
Although Ivan was weakening while the center passed south of Grand Cayman on 12 September, the hurricane still brought sustained winds just below category 5 strength (Table 3) to the island. This resulted in widespread wind damage, and a storm surge that completely over swept the island except for the extreme northeastern portion.
Member Since: Posts: Comments:
165. pottery2
12:53 PM AST on August 21, 2007
Caymanite, good to hear that things are OK. You guys dodged the bullet there man. How were the sea conditions ??
Member Since: Posts: Comments:
164. WXMongrel
4:53 PM GMT on August 21, 2007
Africa image 21/1600UTC



Link
Member Since: Posts: Comments:
163. Bonedog
12:54 PM EDT on August 21, 2007
pottery dont rub it in :) LOL Waiting for a nice fish storm to blow some swell up my window. Getting kinda late in the season to enjoy it without the rubbers on.
Member Since: Posts: Comments:
162. SCEM
4:53 PM GMT on August 21, 2007
Does anyone know where I could find a list of letters for Invests? I understand "L" is the Atlantic Ocean, but what are the other ocean basin letters? Thanks for your help!
Member Since: Posts: Comments:
161. russm1
4:52 PM GMT on August 21, 2007
Posted By: extreme236 at 4:50 PM GMT on August 21, 2007.

Posted By: hosweather at 4:46 PM GMT on August 21, 2007.

Has anyone looked at this recently?

Well, it looks like that is developing ex-92L. Maybe there is still a little tiny tiny chance for development, but development isnt likely


Same thing CMC is showing but none of the reliable models are picking up on it.
Member Since: Posts: Comments:
160. pottery2
12:44 PM AST on August 21, 2007
Bonedog, Groundswell, you guys missed the break here in Trinidad, on Friday. From my sons reports, it was good.
Member Since: Posts: Comments:
159. boiredfish
4:50 PM GMT on August 21, 2007
Depends on if you're talking storm relative vs. earth relative...
Member Since: Posts: Comments:
158. StormJunkie
4:52 PM GMT on August 21, 2007
Guygee, the ADT (dvorak) values are on the CIMSS page on that link I just posted.
Member Since: August 17, 2005 Posts: 26 Comments: 17144
157. littlefish
4:52 PM GMT on August 21, 2007
92L likely to thread the Fla straits or thereabouts. I don't see it anywhere near as north as projection runs have it. Lots of shear and no convection though. Could thread into GOM.
Member Since: Posts: Comments:
156. Bonedog
12:51 PM EDT on August 21, 2007
guygee they dont do Dorvak overland unfortunatley we will have to wait till it remerges and they resume HH recon. I suspect it will be a strong cat 1 at reemergence. Figure about 4 more hours till it does
Member Since: Posts: Comments:
155. gsueagle07
4:49 PM GMT on August 21, 2007
So much for 92L....it won't be Felix....no models are forming it....appears Dr. Lyons comments last night on TWC were correct about conditons not all that favorable for developement.....
154. floridagrrl
4:48 PM GMT on August 21, 2007
Thanks, bonedog and extreme236. Very helpful. And I apologize for snapping at what's his name. I usually have a better sense of humor and judgment, but the 2004 season is still a touchy subject around here. But, alas, good did come from my momentary loss of politeness: I learned the wonders of the ignore function. And life goes on even more beautifully than before. Cheers.
Member Since: Posts: Comments:
153. StormJunkie
4:49 PM GMT on August 21, 2007
Afternoon all. Just on another fly by. Pretty busy today.

CH20Fla, look under the weather links on the
Quick Links page.
Member Since: August 17, 2005 Posts: 26 Comments: 17144
152. Bonedog
12:51 PM EDT on August 21, 2007
np LL
Member Since: Posts: Comments:
151. AEApresident
4:47 PM GMT on August 21, 2007
Does anybody know anything about the storm surge at landfall? Can't find anything in the news.
Member Since: Posts: Comments:
150. guygee
4:44 PM GMT on August 21, 2007
The big hope is that Dean will totally lose its inner structure over land, but right now it look like it still has part of it eye intact, cloud filled and open to the N and NW, but still there.

Anyone have the current Dvorak estimates on Dean?
If Dean hadn't been a CAT 5 12 hours ago I would guess CAT 1, but I don' think it that it has spun down that far yet.
Member Since: Posts: Comments:
149. Bonedog
12:48 PM EDT on August 21, 2007
Ivan didnt make landfall on Grand Caymen its eye passed 30 miles south.

After passing Jamaica, it resumed its more northerly track, and regained Category 5 strength. Ivan's strength continued to fluctuate as it moved west on September 11 and attained its highest winds of 170 mph (275 km/h) as it passed within 30 miles (45 km) of Grand Cayman
Member Since: Posts: Comments:
148. LondonLurker
4:50 PM GMT on August 21, 2007
Thx Bonedog
Member Since: Posts: Comments:
146. extreme236
4:48 PM GMT on August 21, 2007
Posted By: hosweather at 4:46 PM GMT on August 21, 2007.

Has anyone looked at this recently?


Well, it looks like that is developing ex-92L. Maybe there is still a little tiny tiny chance for development, but development isnt likely
Member Since: Posts: Comments:
145. Bonedog
12:46 PM EDT on August 21, 2007
London that is correct. Its not an exact scale. We have seen storms bomb out in pressure but the windfield didnt have time to catch up. Other times winds have been stronger then what is expected for a given MB reading.
Member Since: Posts: Comments:
144. ClearH2OFla
11:59 AM EDT on August 21, 2007
Does any one have the Google earth tropic add ons that you can post. Thanks.
Member Since: Posts: Comments:
143. extreme236
4:45 PM GMT on August 21, 2007
Posted By: floridagrrl at 4:37 PM GMT on August 21, 2007.

extreme236, you've mentioned anticyclones a couple of times today. Can you explain the effect that has on formation? I researched a little before bothering you with the question, but need a little help putting info together. Thanks for your time.


an anticyclone provides favorable winds and good outflow for a system. anticyclones help aid development
Member Since: Posts: Comments:
142. Cregnebaa
4:42 PM GMT on August 21, 2007
"Dean is also the first Category 5 hurricane to make landfall in the Atlantic Basin since Andrew of 1992."

What about Ivan in Grand Cayman in 2004?
Cat 5 sustained winds were recorded
Member Since: Posts: Comments:
141. hosweather
4:45 PM GMT on August 21, 2007
Has anyone looked at this recently?
Member Since: Posts: Comments:
139. LondonLurker
4:41 PM GMT on August 21, 2007
Posted By: guygee at 4:28 PM GMT on August 21, 2007.

The funny thing is that is not the principle at all. The principle is "the stronger the pressure gradient, the stronger the winds".


Cool - so being the 9th lowest pressure hurricane doesn't necessarily = being the 9th strongest (windiest) hurricane?
Member Since: Posts: Comments:
138. SarahFromFLA
4:43 PM GMT on August 21, 2007
That's great news, Cayman!
Member Since: Posts: Comments:
137. Weather456
4:42 PM GMT on August 21, 2007
Taz, see a pic here from 1430 UTC

Member Since: Posts: Comments:
136. Bonedog
12:42 PM EDT on August 21, 2007
Dean was less

Dean was 906 Gilbert was 900
Member Since: Posts: Comments:
135. HopquickSteve
4:40 PM GMT on August 21, 2007
As for predictions for this year...

I don't know what the future holds, we may even be in for only a few more storms...

HOWEVER, 2004 and 2005 taught us that the first big one can be followed by even bigger big ones...

ie Katrina, Rita, Wilma...

Member Since: Posts: Comments:
134. PascagoulaGal
4:41 PM GMT on August 21, 2007
Hi Cayman. So glad everything is ok. TC
Member Since: Posts: Comments:
132. HopquickSteve
4:39 PM GMT on August 21, 2007
Did anyone confirm whether Dean > Gilbert at landfall?
Member Since: Posts: Comments:
131. Tazmanian
4:39 PM GMT on August 21, 2007
it has?
Member Since: Posts: Comments:
130. tillou
4:39 PM GMT on August 21, 2007
Well since I've look around, I would have to agree with the NHC. Nothing developing in the next 48hrs.

See ya'll Thurs.

By NO MEANS do I think this season is over. The month of Sept. could very well be a rough one.
Member Since: Posts: Comments:
129. boiredfish
4:38 PM GMT on August 21, 2007
you sure?
Member Since: Posts: Comments:
128. Inyo
4:34 PM GMT on August 21, 2007
Dean won't survive the crossing of Mexico but the moisture and possibly the upper air circulation will.. some models believe it could bring some rain to drought-stricken California.

It would be nice to see at least some good come out of a storm that has caused harm to so many people.
Member Since: Posts: Comments:
127. Bonedog
12:37 PM EDT on August 21, 2007
floridagrrl an anticyclone is basically a High pressure system. With one above a possible tropical cyclone aids in alowing the thunderstorms to build and grow thus aiding in development. An anticyclone above a storm is what it allows it to vent.

If you look at pictures of dean at its stronger days those wispy high cloudes blowing off the top is what it looks like with an anticyclone above a cyclone
Member Since: Posts: Comments:
126. Weather456
4:37 PM GMT on August 21, 2007
Tazmanian, that wv imagery is from 2am this morning the wave has chnage alot since then.
Member Since: Posts: Comments:
122. floridagrrl
4:34 PM GMT on August 21, 2007
extreme236, you've mentioned anticyclones a couple of times today. Can you explain the effect that has on formation? I researched a little before bothering you with the question, but need a little help putting info together. Thanks for your time.
Member Since: Posts: Comments:
121. Caymanite
4:29 PM GMT on August 21, 2007
Hi all, everyone here busy getting things put back together and getting the businesses up and running.All should be back to normal in a day or 2.Thanks to all on WU who offered prayers and wished us well.Very little damage occured here and for that we are grateful.
Member Since: Posts: Comments:
119. Tazmanian
4:34 PM GMT on August 21, 2007
wow

Member Since: Posts: Comments:
118. groundswell
4:29 PM GMT on August 21, 2007
Bonedog-Ponce Inlet, not much but there was a pressure gradient wind, with a hint of swell, but rideable. You're right, it was not in the swell window for Florida-but had the angle been a little more north, we would have had a larger pulse.
Member Since: Posts: Comments:

Viewing: 168 - 118

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

Top of Page

Dr. Jeff Masters' WunderBlog

About

Dr. Masters (r) co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

Local Weather

Mostly Cloudy
48 °F
Mostly Cloudy

JeffMasters's Recent Photos

Afternoon clouds over Southwest Puerto Rico
Storm clouds gathering over Half Dome
Sierra snow
snowman at Yosemite Falls