The global hurricane season of 2007: was it unusual?

By: Dr. Jeff Masters , 10:22 PM GMT on January 31, 2008

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The year 2007 was a fairly normal year for world-wide tropical cyclone activity. The total number of storms world-wide was 84, two less than the average of 86 (Figure 1). The total number of hurricanes was 43, which is six less than the average of 49. Major hurricanes (Category 3 and higher) and extreme hurricanes (Category 4 and higher) were both slightly below average. No records were broken in any ocean basin for number of storms of any particular category, although the South Indian Ocean did tie its record for number of major hurricanes (seven) and the North Indian Ocean tied its record for number of Category 4 and higher storms (two). One of the North Indian storms (Category 5 Cyclone Gonu) was tied for the strongest tropical cyclone ever observed in the North Indian Ocean. Reliable tropical cyclone records for the globe extend back to 1970, the beginning of the satellite era.


Figure 1. Statistics for the global tropical cyclone season of 2007. The three numbers in each box represent the actual number observed in 2007, followed by the averages from the period 1970-2005 (in parentheses), followed by the record (in red).

Only four Category 5 hurricanes were reported globally in 2007: Tropical Cyclone Gonu (160 mph winds), which hit Oman on June 6 as a Category 1 storm; Super Typhoon Sepat (160 mph winds), which hit Taiwan as a Category 4 storm on August 18; Hurricane Felix (165 mph winds), which hit Nicaragua as a Category 5 hurricane on September 4; and Hurricane Dean (175 mph winds, pressure 905 mb), which hit Mexico's Yucatan Peninsula on August 21 at peak intensity. It is remarkable that half of the globe's Category 5 storms in 2007 occurred in the Atlantic basin, which normally has only about 11% of the globe's tropical cyclones. The globe's strongest tropical cyclone was an Atlantic storm (Dean, 175 mph winds), which is also unusual. I'll have a detailed blog summarizing 2007's notable tropical cyclones next week.


Figure 2. Satellite image of 2007's strongest tropical cyclone at maximum intensity: Hurricane Dean. Post analysis of Dean determined that the storm hit the Yucatan with top sustained winds of 150 knots (175 mph), and a central pressure of 905 mb, the third lowest pressure ever recorded in the Atlantic basin for a landfalling storm. Only the 1935 Labor Day Florida Keys storm (892 mb) and Hurricane Gilbert (900 mb) had lower pressures at landfall.

Jeff Masters

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108. Cavin Rawlins
2:32 PM GMT on February 02, 2008
pottery, enjoy ur carnival. I here T and T has the best carnival in the region.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
107. pottery
1:11 PM GMT on February 02, 2008
20 C is 68 F if you didnt know.
Member Since: October 24, 2005 Posts: 0 Comments: 24788
106. pottery
12:56 PM GMT on February 02, 2008
Good Morning. Nice weather here in Trinidad and Tobago, with a brisk breeze out of the South-West all day long yesterday. Not usual at all. Pulled some moist warm air from the Venezuelan mainland, which made last nights minimum temp go up to 24c instead of the 20c we have been having. Chilly man. Looking at the sat. loops, there is a strong jetstream blowing northeast and creating a large counter clockwise flow over the area, pushing the area of ITCZ convection that is in the central tropical Atlantic back toward north Africa.
It is Carnival here, and the place is buzzing until Ash Wednesday morning. I will try to stay out of trouble till then............
Member Since: October 24, 2005 Posts: 0 Comments: 24788
105. davidw221
12:37 PM GMT on February 02, 2008
I would like to throw an interesting twist to weather forcasting today. In the west the experts say western states are still suffering from a drought, here is the map http://www.cpc.noaa.gov/products/expert_assessment/drought_monitor.pdf

I have read the weather history for the month of january for Neveda, looked into the models for the next month, the west is getting more moisture now than the've had in the last 10 years. Lake Powell and Mead are at their lowest points in recent history, but the storms are freight training thourgh the west. The State of Washington is under a state of emergency with all the snow the've had. California is getting the storms too, and there not ending soon, El-nina is strong and this pattern is going to continue for the next two to three weeks. I posted in here just to get some comments on this subject.
104. aspectre
11:58 AM GMT on February 02, 2008
"A decade ago, Chicago winters meant monumental ice hillocks and caves forming along the lakeshore, skirted by interlocking ice sheets like a giant jigsaw puzzle.
Today, it is rare to see more than a thin frozen shelf or a few small ice floes sloshing in Lake Michigan below the city's skyline.
Decreased ice cover on the Great Lakes, probably caused by increasing air and water temperatures and high winds, is a major culprit in lowering water levels,"
by way of evaporation
That evaporation of what was previously frozen-over water plus cold winds leads to lake-effect snowfall on the leeward side of the GreatLakes.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
102. Cavin Rawlins
3:09 AM GMT on February 02, 2008
January highlights at my blog. I gave my opinion on this recent winter and the U.S./China Economy.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
101. hahaguy
1:18 AM GMT on February 02, 2008
i highly doubt that that thing is going to turn into any in feburary
Member Since: August 12, 2007 Posts: 2 Comments: 2838
100. JRRP
1:04 AM GMT on February 02, 2008
what is the route off this sistem
Member Since: August 16, 2007 Posts: 0 Comments: 6209
96. Cavin Rawlins
12:01 AM GMT on February 02, 2008
cch, cool.....looks like its going to be wet the latter part of this weekend for me.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
95. cchsweatherman
11:36 PM GMT on February 01, 2008
I know that 456, but I just like to have support for my data. Wind shear at this time continues to decrease throughout the Caribbean and over the system, but there is a narrow region of increasing shear between the system and the Caribbean. As 456 had made mention to eariler, there is now an apparent upper-ridge developing in the Caribbean. I must agree with 456 that there is not a closed circulation as of yet, but the circulation developing continues to become better defined and may become closed if it encounters some lower shear overnight. Convection is not all that impressive with only some isolated areas of moderate-to-heavy convection to the south. I do not expect development, if any, until it enters the Caribbean where it will be under the influence of the aforementioned upper level ridge. I state if any since there is some deep, abundant dry air encompassing nearly the entire Caribbean. It will have to contend with this dry air in order to see any development. The bottomline is that it just bares watching, although it remains highly unlikely anything will develop.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
94. Cavin Rawlins
11:28 PM GMT on February 01, 2008
92. cchsweatherman 7:05 PM AST on February 01, 2008

u know u can estimate vorticty from satellite imagery and surface obs. and wind shear can be estimated using wv imagery.....lets say the CIMSS site broke down one for month in August 08 (God forbid). Not wishing it....but it would be an advantage if it does occur.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
93. cchsweatherman
11:28 PM GMT on February 01, 2008
Anyone on right now?
Member Since: April 14, 2007 Posts: 8 Comments: 5169
92. cchsweatherman
11:05 PM GMT on February 01, 2008
Here is the latest IR satellite image of the interest area that I've been monitoring all day. I'm waiting for the latest shear and vorticity maps to be publsihed so that I can do further analysis of this area.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
91. MichaelSTL
11:04 PM GMT on February 01, 2008
Also, as far as naming goes, PAGASA (Philippines) actually gives names to tropical depressions. Imagine if the NHC started doing that...
Member Since: February 22, 2006 Posts: 94 Comments: 32744
89. melly
11:02 PM GMT on February 01, 2008
Being in Palm Beach county Florida, my concerns are during hurricane season.I guess that is being selfish, as there is bad weather 12 months a year. I thought I would sign in and post so I wouldn't forget my password.LOL
The weather is beautiful here.Low 80's. But I keep asking myself "Is it worth it". I have been through 3 hurricane in the last 4 years. The beautiful weather makes one forget how terrible it is during a hurricane. I know cold weather. I grew up in Ohio, and my ex was stationed at Eielson AFB Alaska many years ago. I spent 1 1/2 years up there. I saw temps as low as minus 60. I guess I am looking for a happy medium. No hurricanes, and no freezing weather
88. latitude25
11:00 PM GMT on February 01, 2008
83. clwstmchasr 10:19 PM GMT on February 01, 2008
6 of the storms probably should not have been categorized with names. I believe Dr. Sheets commented and agreed.


It's a gray area.

It's great that technology has advanced to the point that we can pretty much now qualify a systems 5 minutes of glory, or 15 minutes, etc

Where I do not like it is comparing it to historical records, when we did not have that technology, or even historical records where if a ship did not literally run into one, no one would have even know it was there.

Saying we had X amount of systems in 2007, comparing that to historical records, to try and establish a trend to prove an agenda,

is a crock.

.
Member Since: August 24, 2007 Posts: 0 Comments: 3654
87. Cavin Rawlins
10:50 PM GMT on February 01, 2008
58W-17.0N....the storm is on the same lat as my Island - St. Kitts
Member Since: July 24, 2005 Posts: 407 Comments: 19076
86. stormdude77
10:43 PM GMT on February 01, 2008
Good evening!

84. cchsweatherman 6:22 PM AST on February 01, 2008

456, where would you place the center for this system?

I'm not W456, but I would place the ''center'' roughly around 17N, 57W... JMO...
85. MichaelSTL
10:34 PM GMT on February 01, 2008
saying that 6 of the storms probably should not have been categorized with names

IMO, they should have been named - after all, you could say the same thing about some of the storms in 2005, as well as just about any other year (some of which were even weaker and shorter-lived and less of a threat than the storms in question). The only storms that shouldn't of been classified are the depressions that fail to develop (and are not forecast to do so) and are in the middle of the Atlantic, like TD 15 last year; if they are near land, then that is different for obvious reasons (recall Humberto - although that was forecast to strengthen into a storm). In addition, there are plenty of examples of such storms in other basins (especially last year; for example, the West Pacific had several storms that lasted for only a day, so it isn't surprising that it had a ACE index 30% below normal - despite also having 8 major hurricnae strength typhoons, the first time that ever happened with such a low ACE index; the Australia region was even worse - near average activity but 3 intense storms and an ACE index 55% below average).
Member Since: February 22, 2006 Posts: 94 Comments: 32744
84. cchsweatherman
10:22 PM GMT on February 01, 2008
456, where would you place the center for this system?
Member Since: April 14, 2007 Posts: 8 Comments: 5169
82. cchsweatherman
10:19 PM GMT on February 01, 2008
Thanks for confirming what I have been watching all day long 456. We may have something interesting afoot, but it is too soon to tell. Here are the facts that I have been able to derive.
1. Shear has been steadily decreasing throughout the day over the system.
2. A broad -what now appears to be surface- circulation has developed and west winds are easily visible on satellite imgaery.
3. There has been some increasing convection around the SE quadrant of the circulation that had not been present during the morning and early afternoon hours.
4. It is heading into the Caribbean where surface water temps remain favorable for tropical/subtropical development.
5. There is a massive abundance of dry air in the Caribbean, quite possibly the limiting factor for development shown by the NOGAPS model.

All in all, we will need to keep watching this area just in case it tries to pull a surprise out of its hat.

Do you all agree with my assessments?
Member Since: April 14, 2007 Posts: 8 Comments: 5169
81. Cavin Rawlins
10:02 PM GMT on February 01, 2008
CCH, I have been wathcing the system throughout the day too. One thing i notice is the circulation is closing off. Some reports out of the islands during the day were from 300 to 360 degrees indicating some northwest/north winds. Also Low level winds at CIMSS showed the circulation becoming define but not totally closed off yet as seen on RGB imagery. This is subtropical in nature with an upper level circulation at 200 hpa and a flat thermal enviroment at 100 hpa. I dont expect much of this in the next 24-48 hrs. Beyond 48 hrs the NAVY NOGAPS showed the system entering the caribbean encountering favorable upper level winds in assciation with an upper ridge but no development...wierd?...not totally...other factors must be considered.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
80. catastropheadjuster
9:45 PM GMT on February 01, 2008
Are you all ready for ground hog day tomorrow? I am I hope winter is over. It's been very cold this year. I already booked marked the page so I can watch it in the morning by 7:30 am we will know. If he says 6 more weeks I am going up the to shot him. LOL
Sheri
Member Since: August 24, 2006 Posts: 21 Comments: 3683
79. cchsweatherman
9:40 PM GMT on February 01, 2008
How's our favorite mother of seven doing? Haven't heard from you in a while. Just keeping an eye on the little disturbance out in the CATL. RAMSDIS has a floater up on it.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
78. CatastrophicDL
9:33 PM GMT on February 01, 2008
Hi CC, Michael, everyone! Michael I thought the prediction for the decrease in La Nina was April to May of 2008? CC, I agree that convection looks to be flaring up a little on that area of interest.

I hope everyone is warm and cozy. I'm heading out to shovel a few inches of snow. Normally I love the snow, but we are above average this year with new snowfall every 2 days or so. I get some good exercise thought! :o)
Member Since: September 3, 2007 Posts: 3 Comments: 1519
77. cchsweatherman
9:11 PM GMT on February 01, 2008
Good evening 456. Could you comment on the area of interest near the Virgin Islands? I have been watching it all day and I have seen what appears to be a broad circulation in the lower-to-mid levels of the atmosphere with some modest convection encircling it to the east. Seems like it is embedded in an upper-level trough since shear maps indicate that shear has dropped off quite dramatically over the area. I'm not expecting development, but could it entirely be possible that we may see an invest? RAMSDIS has a floater over the disturbance. Thanks.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
76. NEwxguy
8:25 PM GMT on February 01, 2008
STL, when this La Nina started,no one expected this strength and the long duration.
Member Since: September 6, 2007 Posts: 887 Comments: 15965
75. NEwxguy
8:24 PM GMT on February 01, 2008
THE PRECIPITATION FORECAST FOR FEBRUARY ALSO LARGELY REFLECTS LA NINA
COMPOSITES, WHICH INDICATE MEAN DRY CONDITIONS ACROSS THE SOUTHERN U.S. AND
MEAN WET CONDITIONS PRIMARILY IN TWO AREAS OF THE NORTHERN U.S.: THE PACIFIC
NORTHWEST AND FROM THE OHIO AND TENNESSEE VALLEY NORTHWARD INTO THE GREAT LAKES
REGION. THE PROBABILITY OF BELOW NORMAL PRECIPITATION IN THE SOUTHEAST HAS BEEN
REDUCED DUE TO RECENT ATMOSPHERIC CIRCULATION AND PRECIPITATION PATTERNS. THE
FLORIDA PENINSULA CONTINUES TO HAVE THE GREATEST PROBABILITY FOR BELOW NORMAL
PRECIPITATION.
Member Since: September 6, 2007 Posts: 887 Comments: 15965
74. MichaelSTL
8:13 PM GMT on February 01, 2008
While I’m enjoying pointing out these uncommon phenomena, I’d also point out that even though both the northern and southern hemispheres have both seen some record cold events in the past 6 months, that doesn’t necessarily equate to “climate change”. Still, something seems afoot as we are seeing more and more events like this. Maybe the massive La Niña now stretching across the Pacific ocean has something to do with this.

I think that is likely; it is even bigger in area than the record 1988 La Nina, and that one also peaked in December, the current one is STILL strengthening - only one other La Nina peaked this late and wasn't anywhere near as strong (-2.2 Nino 3.4 last update):



I also think there is a good chance that it will remain thoughout the year with some weakening and strengthen again next fall, like 1998-2000 (the 1988 La Nina slowly declined to neutral by the end of 1989).
Member Since: February 22, 2006 Posts: 94 Comments: 32744
73. NEwxguy
8:10 PM GMT on February 01, 2008
Looks like we will continue with La Nina conditions for the forseeable future

SSTS IN THE EASTERN EQUATORIAL PACIFIC ARE WELL BELOW NORMAL INDICATING RATHER
STRONG LA NINA CONDITIONS. SSTS IN THE PACIFIC HAVE BEEN CONSISTENTLY BELOW
NORMAL ALONG THE EQUATOR IN THE PAST SEVERAL WEEKS, WITH SST ANOMALIES NOW MORE
THAN 1 DEGREE C BELOW NORMAL FROM AROUND 165E TO THE SOUTH AMERICAN COAST WITH
ANOMALIES OF -2 C FROM THE DATE LINE TO 110W. OCEAN TEMPERATURES IN THE UPPER
200 M OF THE EASTERN PACIFIC REMAIN WELL BELOW NORMAL, SUGGESTING THAT SST
ANOMALIES WILL PERSIST NEAR THEIR CURRENT LEVELS INTO FEBRUARY.
Member Since: September 6, 2007 Posts: 887 Comments: 15965
72. Ivansrvivr
7:53 PM GMT on February 01, 2008
I had no idea it was there, was cruising thru the blogs ahd checked out Dr. Masters and there she is. Looks like it has potential. I'd LOVE to see go south of cuba, then Fl woud get alot of rain.
71. Cavin Rawlins
7:52 PM GMT on February 01, 2008
Good afternoon to all
Member Since: July 24, 2005 Posts: 407 Comments: 19076
70. CaneAddict
7:31 PM GMT on February 01, 2008
FreeWebs.com/JapWeather but it is still being built since about a week ago i had to redo it.
Member Since: October 5, 2007 Posts: 3 Comments: 2151
69. cchsweatherman
7:25 PM GMT on February 01, 2008
CaneAddict, what is your website? I would like to check it out. You can check mine out also. There is a link to it in Comment 63.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
68. CaneAddict
7:15 PM GMT on February 01, 2008
Hello again folks! As you probably notice i only come out to chat when there is something tropical going on or an area with potential. I also have noticed that area in the Atlantic with what appears as a broad mid-level circulation. I think it requires some watching and we may possibly get an investigative area out of it. So i will be keeping my eye on it as well and i will post an summary on it on my website tonight. If convection continues to fire with it then we will likely see a invest soon. Something to watch!
Member Since: October 5, 2007 Posts: 3 Comments: 2151
67. Ivansrvivr
6:43 PM GMT on February 01, 2008
It was actually Northeasterly/southeasterly at surface with strong low level swjet(5000ft). I was able to see it from the ground up.
66. Ivansrvivr
6:41 PM GMT on February 01, 2008
Interesting p3 water restrictions posted.
Thing is the cities aren't going to enforce them. My father is civil engineer, has designed much of the drainage, water plants etc for municipalities from broward to brevard. The mayors, city councils know that our water isn't from L.O., the farmers(lobby money) wanted these restrictions. they are dependent on the lake first. Municipalites are very unhappy about this and are refusing to enforce it. Have you heard about 1 ticket yet???
65. cchsweatherman
6:37 PM GMT on February 01, 2008
I heard that Boynton Beach received 10 inches within a three hour span one evening last week as an easterly sea breeze and a westerly sea breeze converged right over your area. Hope there wasn't any damage there.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
64. Ivansrvivr
6:35 PM GMT on February 01, 2008
We got creamed last week in the boynton flood, 3 inches. had storms next afternoon, not much since.
63. cchsweatherman
6:33 PM GMT on February 01, 2008
61. Ivansrvivr 1:28 PM EST on February 01, 2008
CC, haven't seen u in a bit how you doin?


I've been doing great man. Nice to hear from you again. How's everything been with you? Get affected by the storms yesterday or did they miss you? I've created a much improved website at the same address as my old one at Link if you want to check it out and leave a comment.

Well, I'm glad to hear from you man.

Another note, taking a look at the latest visible imagery of the interest area, it seems like the system has begun to fall apart as convection has begun to die and shear has begun to take firm hold. There still is a broad low to mid level circulation in the area.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
62. Ivansrvivr
6:31 PM GMT on February 01, 2008
With this La Nina, I wouldn't rule anything out. I just jokingly said the other day that if it gets any warmer here, it may trigger a winter hurricane season. Better stop with the jokes.
61. Ivansrvivr
6:28 PM GMT on February 01, 2008
CC, haven't seen u in a bit how you doin?
60. JRRP
6:05 PM GMT on February 01, 2008
un apagon mundial por 5 minutos mmmmmm
cuando seria eso
Member Since: August 16, 2007 Posts: 0 Comments: 6209
59. cchsweatherman
5:10 PM GMT on February 01, 2008
It appears that the broad circulation I had mentioned about half an hour ago has become much better defined in visible imagery with a slight increase in convection.
img src="Photobucket" width="" height="" alt="" />
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58. Smyrick145
4:47 PM GMT on February 01, 2008
Thanks for your input Hurricane 23.
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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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