By: Dr. Jeff Masters , 12:33 PM GMT on July 24, 2007

The July 2007 issue of Scientific American has an article called "Warmer Oceans, Stronger Hurricanes" (referred to as "Warmer Water, SUPER HURRICANES" on the cover). The article is written by Dr. Kevin E. Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research, and a lead author on the landmark 2007 climate report issued by the UN's Intergovernmental Panel on Climate Change (IPCC). The article makes the case that "evidence is mounting that global warming enhances a cyclone's damaging winds and flooding rains." The article presents some solid evidence to substantiate that point of view, which I will share below. However, I was disappointed in the general tone of the piece, which was over-hyped and did not paint an objective view of the current scientific thinking on the global warming/hurricane issue.

The hype
First off, the reader is hit with a dramatic full-page artist's depiction of the global super-hurricane of the future--a massive 5000-mile diameter Caribbean storm the size of North America. The storm's 200-mile eye is wider than the Florida Peninsula! Whoa, I said when looking at the whopper "SciAmicane". No doubt many readers perusing the magazine, trying to decide whether to buy it, had the same reaction and plunked down their $5 to read about this grim threat. OK, lets talk reality here. The largest tropical cyclone on record, Supertyphoon Tip of 1979, had a diameter of 1380 miles--less than one third the size of the SciAmicane. A storm like the SciAmicane cannot physically exist on Earth unless the oceans were to super-heat to about 122°F (50°C). Only an asteroid impact or similar calamity could create such a hypercane. Even the most extreme global warming scenarios do not heat the oceans to 122°, so the SciAmicane is there to sell magazines, not to illustrate what global warming might do to hurricanes.

Figure 1. Comparison of sizes: the Earth, the largest tropical cyclone on record (Supertyphoon Tip of 1979, 1380 miles in diameter), and the recently discovered hurricane-like vortex on Saturn (the Saturnicane). The "SciAmicane" is about the same size as the Saturnicane--5000 miles across.

The article also calls attention to 2004, when "an unprecedented four hurricanes hit Florida, and 10 typhoons made landfall in Japan". I've erroneously made this statement, too, but the truth is that Japan was hit by only four typhoons in 2004. Ten tropical cyclones that were of typhoon strength at some point during their life did hit, yes, but six of these had decayed to tropical storm or tropical depression strength by the time they hit Japan. The article then refers to a "consensus explanation" emerging to explain recent hurricane activity patterns, and "that explanation forebodes meteorological trouble over the long term." I'd say that the issue is still very much under dispute. In fact, the consensus statement on hurricanes and climate change adopted by the World Meteorological Organization in December 2006, in response to the recommendations of a panel of 125 hurricane researchers was thus: "Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point." Trenberth's article gives a list of four publications to read in the "more to explore" section, but none of these include the recent articles that call into question the strength of the global warming/stronger hurricane connection. (I apologize for not reviewing the many excellent articles that have appeared on this subject of late!)

The good science
There's quite a bit of good science in the article, which is worth reading if one keeps in mind its biases. In particular, I like the discussion of how global warming has affected precipitation and atmospheric water vapor. The 0.6°C (1.0°F) rise in Sea Surface Temperatures (SSTs) globally since 1970 has increased water vapor in the atmosphere by 4%, thanks to increased evaporation. This in turn has led to an 8% increase in global precipitation. Trenberth makes the point that no given hurricane can be blamed on global warming, but one can say 8% of a given storm's rainfall is due to global warming. There's also a nice discussion about how weaker than normal trade winds over the tropical Atlantic in 2005 caused less evaporational cooling than normal, allowing the ocean to heat to record temperatures. Finally, the conclusion of the article is one I certainly agree with:

We would all be wise to plan for more extreme hurricane threats.

Both theory and computer models predict a 3-5% increase in hurricane winds per degree C increase in tropical SSTs, and there is concern that the actual increase may be much more than this.

Jeff Masters

For a technical treatment of hypercanes, see Dr. Kerry Emanuel's paper, Hypercanes: a possible link in global extinction scenarios.

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2291. MrNiceville
3:29 PM GMT on July 26, 2007
Thanks, SW.

Good info - agree on the GOM blob - 20kts to 25kts shear, correct?
2290. texascanecaster1
3:27 PM GMT on July 26, 2007
okay that blob is not even close to a ts. Hwoever if i was the nhc i would have named it a disturbance numberl. The fact that hasn't been done when it should have been done dissapoints me. So what if it appears it won't develop? when you gte something like this in the tropics at this time of year it has to at least be named a disturbance number even if it is not going to develop.
2288. CaicosRetiredSailor
2:53 PM GMT on July 26, 2007
To read:

WU members discuss evacuation

A compilation of comments WU members left on this Blog concerning evacuation in a more accessible form.
SEE: Link

I have copied these comments, (over 120 comments by about 40 WU members)and it is my first WU blog entry.

Member Since: July 12, 2007 Posts: 0 Comments: 6115
2287. MrNiceville
2:50 PM GMT on July 26, 2007
man - these crickets sure are loud...
2286. MrNiceville
2:40 PM GMT on July 26, 2007
finally at the office - these soccer camps are gonna kill me!

It looks like the convection is deepening in the GOM, but there's 20 - 25kts of shear over it. Hard to make a case for development...

The winds at all levels head N(so are they northerly or southerly?) to NE, so I just can't buy the NW movement - that L is too far west at the moment...

As to rules, I checked in the rear view mirror, guygee - no warts on my nose or face... (grin)

(Edit) Oh yeah - almost forgot - NEW BLOG!
2285. IKE
2:16 PM GMT on July 26, 2007
Member Since: June 9, 2005 Posts: 23 Comments: 37938
2284. moonlightcowboy
2:10 PM GMT on July 26, 2007
LOL, guygee!

For rules...I like an old tune by Tanya Tucker that has a line it..."There's a tree out in the backyard, that never has been broken by the wind...cause it was strong enough to bend!"
Member Since: July 9, 2006 Posts: 184 Comments: 29617
2283. guygee
2:06 PM GMT on July 26, 2007
Posted By: guygee at 12:58 PM GMT on July 26, 2007.
...if you quote me and respond with LOL, without offering any countering evidence or reasoning, then yes, you are a troll. It is not my rule, it is a fallacious argument under the Rules of Informal Logic. It is an Ad Hominem attack. ...
I wish I had never written this, LOL.
I forgot that rules are made to be broken, LOL.
It is the sacred right of every American, it is the American Way! LOL!
(just procrastinating while trying to decide which chore to tackle first, LOL).
Member Since: September 16, 2005 Posts: 0 Comments: 3434
2282. sonofagunn
2:06 PM GMT on July 26, 2007
I guess shear *was* favorable when I posted that link, but it's just been updated with the latest map which shows it less favorable now...
Member Since: June 12, 2006 Posts: 0 Comments: 203
2281. moonlightcowboy
2:05 PM GMT on July 26, 2007
sonofagun, I see 20-30 kts of upper shear in the GOM in the cimss.
Member Since: July 9, 2006 Posts: 184 Comments: 29617
2280. weathers4me
2:01 PM GMT on July 26, 2007
Are the steering currents in the GOM pushing all that convection into TX still?
Member Since: May 24, 2007 Posts: 0 Comments: 118
2279. quante
2:01 PM GMT on July 26, 2007
Anyone have a link testing the accuracy of long range forecasts to actual outcome in predicting formation and location of tropical system? In my wholely unscientific experience they are almost never right past 2 days.
Member Since: August 2, 2006 Posts: 0 Comments: 329
2278. sonofagunn
1:59 PM GMT on July 26, 2007
CIMSS says shear is favorable in the Western GOM.
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2277. Drakoen
1:58 PM GMT on July 26, 2007
TCC if you looked at the cyclone phase diagram its only 2 days...
Member Since: October 28, 2006 Posts: 57 Comments: 32489
1:55 PM GMT on July 26, 2007
The convection is getting intense and widespread in the gulf I dont know if it will hold into Texas or if Texas will even be its destination. The GFS seems to be off on this one. The NAM has been more accurate. um....

er lol.?

Well anywho TCC theres not much circ there - you can tell on the WV when it dissipated earlier but that could change quickly. especially as more stuff moves in (waves moisture etc...) from both the east and west.

It may get invest status just because of the critical situation in Texas.
Member Since: May 22, 2006 Posts: 188 Comments: 24743
2275. MichaelSTL
1:54 PM GMT on July 26, 2007
Regarding the supposedly "slow" start to the season (when in fact it has been the opposite, unless you are referring to the East and/or West Pacific; Cosme was one of the latest first hurricanes on record and the WPAC has had about 1/2 of their normal activity to date), here is a comment that I posted last year (unfortunately, the link I got it from is broken now, and of course the La Nina last year went bust and turned into El Nino - but the principle remains):

Posted By: MichaelSTL at 7:40 PM CDT on July 07, 2006.

Remember that this year started with La Nina conditions? Well, this page is interesting especially in what it says about La Nina year hurricane seasons:

It does seem to make much different to some folks. They hear all about the Hurricane season forecast for various sources then come Mid- August when only 1 or 2 Tropical cyclones have developed they start complaining about busted forecasts and media hysteria. The fact is La Nina hurricane seasons are Notoriously slow starting seasons.

The above can indeed be confirmed by looking at past seasons, and it doesn't really matter much how strong La Nina gets or how fast it develops either (an extreme example is 1969, with 18 storms; the third storm developed in mid-August and made landfall as a 190 mph Cat 5).
Member Since: February 22, 2006 Posts: 94 Comments: 32744
2273. texascanecaster1
1:52 PM GMT on July 26, 2007
ok guys if seen sat. pics and model runs for today. gfs ngp uk all still showing development off of that new wave that is going to leave the african mainland tomorrow about 3 days after it emerges. We got major problems in texas three lighting strikes recently and three houses are on fire in my subdidivision sirens all over the place. In any event the low in the boc look like a full blown tropical storm inf fact it resembles tropical storm allison in appearence. Whil upper level still arent great i think that if this appearence persist during the day today this afternoon the nhc may jump on it like they did with barry. Other than that i do not think that the new wave over africa will develop that quickly after it emerges lik the models are suggesting. I think probably when it reaches the high tchp levels near the antillies it will develop. Also nogap shows a storm forming from a mid atlantic wave that moves near the carrib at the end of 7 days. That is a more liklely developmental scenerio. In any event at anytime time now we could see a system rapidly form from a wave or a trough and become a storm so the tropics need to be watched very carefully. If i was in charge at the nhc i would be more concerned with that gulf blob especially with the circular appearence and the heavy convection at the center.

2272. texascanecaster1
1:41 PM GMT on July 26, 2007
morning all. I see that wee have a lot of convection the gom. also i see that new gfs runs are out. depending on what the situation is i may or may not blog a tropical weather disscussion today. however that thing in the gulf is getting better organized so more problems for me here in texas. I have jsut turned on my computer this morning so i need to see some stuff before i can tell whats going on.
2270. amd
1:38 PM GMT on July 26, 2007
It seems that the slow start to the hurricane season as caused some to once again question the notion of global warming.

Tempest In A Teapot


Posted 7/25/2007

Global Warming: A private firm's downgrade of its hurricane forecast raises an obvious question: If scientists can't get near-future projections in a limited area right, how can they predict the climate decades from now?

Related Topics: Global Warming

A reasonable response is: They can't. But the global warming climate of fear did not blow in on the soft breezes of reason, but by the storm winds of emotion.

Forecaster WSI Corp. said Tuesday that the season ending Nov. 30 will bring 14 named storms, six of which will grow into hurricanes, three of them major. WSI's initial forecast was for 15 named storms, eight hurricanes and four majors.

Why the change? "Because," said WSI forecaster Todd Crawford, "ocean temperatures have not yet rebounded from the significant drop in late spring."

Could it be that the 2007 hurricane season is turning out to be as overrated as 2006? Remember last year's predictions that we were in for a brutal spell of storms? It had been quiet, they said, and we were due for a series of Katrina-like hurricanes. But as we wrote last November, as the much-dreaded '06 season whimpered to a close, the storm year came in like a lamb and went out the same way.

For years, the Greenshirts have told us that emissions of carbon dioxide resulting from man's addiction to fossil fuel-based energy are turning the planet into a sweltering hothouse. The United Nations' Intergovernmental Panel On Climate Change has projected a temperature increase of 2 to 11.5 degrees Fahrenheit for the 21st century due to the greenhouse effect.

As a result, alarmists say, ice caps will melt, glaciers will thaw and sea levels will rise as much as 20 feet, causing floods and death in low-lying areas. Storms are also predicted to increase in both frequency and intensity.

To prevent this coming Category 5 cataclysm, we're supposed to shell out trillions of dollars and gladly adopt Spartan lifestyles. Instead of trying, as their grandparents did, to see how many bodies they can squeeze into a telephone booth, today's college kids are expected to see how many they can get in a Prius.

Yet the fact remains: The local weatherman can't forecast more than about 10 days out, and neither can the experts tell us how warm, or cool, the planet is going to be in 2100, 2075 or even 2050.

Even short-term predictions have been off. James Hansen, NASA scientist, predicted a 0.45-degree Celsius (0.81-degree Fahrenheit) rise in global temperature from 1988 to 1997. But in reality (a place environmental activists rarely visit) the increase was a mere 0.11-degree Celsius.

We hope no one in Hansen's neighborhood relies on him to tell them when it's going to rain or when they'll need a coat and hat.

Setting aside the hubristic notion that alarmists know what the right temperature is, too many other factors besides the greenhouse effect influence climate for them to declare they know exactly, or even approximately, what's coming. Solar activity, for instance, is among the most powerful, as are the El Nino and La Nina phenomena.

We also question the concept of a "global" temperature. How could such a thing be measured when weather stations dot rather than blanket the Earth? Danish physicist Bjarne Andresen, a professor at the University of Copenhagen, made sense earlier this year when he said it's "impossible to talk about a single temperature for something as complicated as the climate of Earth.

"A temperature can be defined only for a homogeneous system (and) climate is not governed by a single temperature," he said. "Rather, differences of temperatures drive the processes and create the storms, sea currents, thunder, etc. , which make up the climate."

The formula for a climate of fear, though, requires nothing more than a lot of thunder and a bit of heat generated by political activists.
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2267. Drakoen
1:35 PM GMT on July 26, 2007
lol jp.
whats with the italics?
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2266. MichaelSTL
1:34 PM GMT on July 26, 2007
It is better to use the image from SSD, which goes further east:

Member Since: February 22, 2006 Posts: 94 Comments: 32744
2264. Drakoen
1:30 PM GMT on July 26, 2007
we have to keep track of it from the EUMETSAT for now.
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2263. ryang
1:29 PM GMT on July 26, 2007
SAL is fairly weak and moving west, and the wave isn't on water yet.
Member Since: August 25, 2006 Posts: 329 Comments: 12479
2262. weatherguy03
1:29 PM GMT on July 26, 2007
Hey I dont take you to the woodshed GR!..LOL
Member Since: July 5, 2005 Posts: 592 Comments: 29708
2261. ryang
1:28 PM GMT on July 26, 2007
It looks healthy and fairly strong/large...

Member Since: August 25, 2006 Posts: 329 Comments: 12479
2260. weatherguy03
1:28 PM GMT on July 26, 2007
03 - for those of us who are Wx amateurs, what's a line of convergence?

Winds of opposite directions conveging to produce T-storms. SW winds ahead of that trough, winds from the South coming out of S to SE. This will cause lift and produce T-storms, especially over the warm GOM.
Member Since: July 5, 2005 Posts: 592 Comments: 29708
2259. GetReal
1:27 PM GMT on July 26, 2007
OK thanks for the clarification (lesson) Bob...
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2258. Drakoen
1:27 PM GMT on July 26, 2007
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2257. weatherguy03
1:26 PM GMT on July 26, 2007
GR. It would be very hard GR, epsecially the way the Upper Level winds are right now. And something I mentioned yesterday with this area. Its moving at a good clip to the NNW, while the trough isnt going anywhere. Its in a no win situation.
Member Since: July 5, 2005 Posts: 592 Comments: 29708
2256. drusierDMD
1:21 PM GMT on July 26, 2007
an additional frame can be seen on the loop 12Z (that you cant see one the single image 6Z)

probably will be fixed before any1 can confirm

2255. TropicalNonsense
1:21 PM GMT on July 26, 2007
Member Since: July 3, 2007 Posts: 0 Comments: 524
2254. Drakoen
1:20 PM GMT on July 26, 2007
According to the GFS we should see some action on Saturday.
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2252. GetReal
1:19 PM GMT on July 26, 2007
Posted By: weatherguy03 at 1:07 PM GMT on July 26, 2007.

those t-storms have blown up due to convergence. You can see the convergence line move north and then there is the blowup of storms. Thats all it is, just like yesterday.

Bob I know that I may regret this, and I'm sure you will take me out to the WU wood shed, but here it goes... Bob so what you are saying is that it is impossible, or highly unlikely, for a low pressure area to spinup out of a convergence zone?
Member Since: July 4, 2005 Posts: 204 Comments: 8972
2251. Drakoen
1:17 PM GMT on July 26, 2007
yea ryang its very large and it probably what the GFS is picking up on.
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2250. ryang
1:17 PM GMT on July 26, 2007
The GFS model forecasts that this wave will be a strong tropical cyclone near 15 North, 48 West by next Thursday.
Member Since: August 25, 2006 Posts: 329 Comments: 12479
2248. ryang
1:16 PM GMT on July 26, 2007
Guys, the next wave about to exit, is a real threat.
Member Since: August 25, 2006 Posts: 329 Comments: 12479
2247. Drakoen
1:15 PM GMT on July 26, 2007
I see. I would think because of the time frame that it would be associated with the wave coming of Africa. Its fairly large in size. we will see.
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2246. hurricane23
1:13 PM GMT on July 26, 2007
Posted By: Drakoen at 09:09 EDT le 26 juillet 2007.

morning everyone. The GFS still forecasting development?

LOL look up in the blog...I posted a pic for some entertainment.
Member Since: May 14, 2006 Posts: 8 Comments: 13857
2245. guygee
1:13 PM GMT on July 26, 2007
MrNiceville- Thanks for clarifying. Civility seems to be an ancient art these days, it is really a step beyond logical rules and would make the blog much more enjoyable if everyone practiced it. I am afraid sometimes I have lost the art and come off stone cold, but that is not my intent.

LOL, I guess I can be a bit humor-impaired at times too. I wouldn't presume to make up personal rules for this blog, but Roberts Rules of Order is probably a step above the simple rules of logic in helping people get along.

BBL, have a good one!
Member Since: September 16, 2005 Posts: 0 Comments: 3434
2244. IKE
1:12 PM GMT on July 26, 2007
Rain headed for New Orleans....

Member Since: June 9, 2005 Posts: 23 Comments: 37938
2243. Drakoen
1:12 PM GMT on July 26, 2007
yea hurricane23 thats the problem when its gets on water it they loose some of the convection.
Member Since: October 28, 2006 Posts: 57 Comments: 32489
2242. hurricane23
1:11 PM GMT on July 26, 2007
Lets keep an eye on the wave about to exit africa as the GFS is picking up on it and really cranking it for the first time this year.As we move into august next week our chances for development continues to go up.

Lets see if it can maintains its thunderstorm activity once it moves of the african coast.
Member Since: May 14, 2006 Posts: 8 Comments: 13857
2241. MrNiceville
1:10 PM GMT on July 26, 2007
03 - for those of us who are Wx amateurs, what's a line of convergence?

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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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