Warmer Water, SUPER HURRICANES

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

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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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240. Patrap
1:35 PM CDT on July 24, 2007
GOES IR loop GOM Link
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239. Drakoen
6:32 PM GMT on July 24, 2007
Posted By: sporteguy03 at 6:31 PM GMT on July 24, 2007.

Isn't the Nogaps and UKMet quiet models and not as aggressive with development?


right. They are not like the CMC or sometimes the GFS. They are considered "reliable".
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238. IKE
1:31 PM CDT on July 24, 2007
Buoy 42055 in the Bay of Campeche.....

"5-day plot - Wind Direction Wind Direction (WDIR): SE ( 130 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 11.7 kts
5-day plot - Wind Gust Wind Gust (GST): 15.5 kts
5-day plot - Wave Height Wave Height (WVHT): 1.6 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 5 sec
5-day plot - Average Period Average Period (APD): 3.4 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.96 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): +0.00 in ( Steady )
5-day plot - Air Temperature Air Temperature (ATMP): 84.7 F
5-day plot - Water Temperature Water Temperature (WTMP): 85.5 F
5-day plot - Dew Point Dew Point (DEWP): 75.6 F
5-day plot - Heat Index Heat Index (HEAT): 93.6 F"
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237. Drakoen
6:31 PM GMT on July 24, 2007
if you look at this graphic most of the ITCZ is on or above 10N. The UKMET might be on to something.
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236. sporteguy03
6:30 PM GMT on July 24, 2007
Isn't the Nogaps and UKMet quiet models and not as aggressive with development?
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235. sporteguy03
6:28 PM GMT on July 24, 2007
JP,
Severe weather in FL again! No Tropics!
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234. seabreeze97
6:23 PM GMT on July 24, 2007
tcc, read your blog...things sure does seem to be cranking up.

Is the blob in the boc the real thing?
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233. Drakoen
6:27 PM GMT on July 24, 2007
that may be the area to watch if you look at the UKMET 12z model run it starts something in that general area.
UKMET
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229. seabreeze97
5:56 PM GMT on July 24, 2007
sorry,

I didn't mean it that way.

I just meant people should try to get out of harms way. Why stay, then cry out for help when no one is there...hello



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228. Drakoen
6:18 PM GMT on July 24, 2007
Posted By: stoormfury at 6:04 PM GMT on July 24, 2007.

I might be wrong and subject to correction. To me there seems to be an area of suspicion between 10-15 N 35-40W. I will continue to monitor this area


RAMSDIS is watching that area as well.
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227. hurricane23
2:18 PM EDT on July 24, 2007
If you live in the southflorida area meaning miami dade and broward counties be careful as a severe thunder storm warning is now in affect for our area.

Storm is moving SW with rotation indicated by doppler radar.

ffff
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223. EdMahmoud
6:09 PM GMT on July 24, 2007
Moon Light- official word from the governor's office in Texas after the Rita fiasco- in the Houston area, there are designated evacuation zones, the people in the zones closest to the coast are now supposed to leave first, and people in the inland zones, depending on storm intensity, are staged sequentially by zone. A new contra-flow plan has been set up on the highways out of Houston to get people out. But part of the plan is, unles sthey live in a flood plain or a mobile home, people not in a designated evacuation zone, and the Cat 5 zone gets as far inland as Pasadena and the SE parts of the I-610 loop, people are supposed to stay put and prepare to ride out the storm, including provisions for several days without electricity, at home, so the people who really do need to leave, can.
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222. quante
5:51 PM GMT on July 24, 2007
It must have been 2004, but I remember an incredible satellite photo of three or four active systems, lined up between US and Africa. Can anyone find and post that pic?
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221. Drakoen
6:10 PM GMT on July 24, 2007
UKMET 12z 144 hours out. Still hinting something...
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217. stoormfury
5:59 PM GMT on July 24, 2007
I might be wrong and subject to correction. To me there seems to be an area of suspicion between 10-15 N 35-40W. I will continue to monitor this area
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216. moonlightcowboy
5:56 PM GMT on July 24, 2007
Posted By: EdMahmoud at 5:55 PM GMT on July 24, 2007.
I don't know why people keep acting like I recommended staying put for a Cat 1 on the coast. What I said, for most places, a Cat 1 or 2 will not do significant damage to a well built home, but if one were near the coast, leave anyway, because every now and then, and I gave the example of Charley, a Cat 2 can become a Cat 4 fairly quickly.


...lol, Ed, take it easy. I think we understood what you meant. Your intentions were noble. Remember, there are people trying to learn (myself included for sure) about what to do.

I know one family that lived nearly 70 miles inland and were without power alone for nearly two weeks. They say they will evac and never subject themselves to those kind of conditions again.

The rule is (Patrap has a good one); but, basically it means be prepared and have a good plan(maybe an alternate plan even); but mostly, "listen" to your local authorities and act accordingly.

I like what Stormy2 said earlier, and it sounds like his planning is thorough!
Member Since: July 9, 2006 Posts: 184 Comments: 29610
215. EdMahmoud
5:58 PM GMT on July 24, 2007
leftovers,
to make a long story short...tell it to the neighbor who couldn't leave after the storm because of live electrical wires all over the place. He had to stay put with very little to survive on...Not to mention the absence of gasoline. A real mess...

So anyone who is talking the stay behind stuff is full of air...



Well, a Cat 3 landing near Galveston could knock out electricity as far inland as La Grange and College Station. So you'd recommend the entire Houston area, including the most distant suburbs, should take to the roads to avoid it.


For that matter, we went about 12 hours without electricity after Hurricane Rita, people 15 miles away in Harris County (towards Humble) that were served by Entergy went up to two weeks, and I didn't see any evidence of winds even reaching hurricane force anywhere in Harris County.

So, everyone within 50 miles of the coast should jam up the interstates and flee inland because they might lose power in a Cat 1?
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214. hurricane23
2:03 PM EDT on July 24, 2007
No thats some serious convection!!!

ggg
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212. EdMahmoud
5:56 PM GMT on July 24, 2007
I could edit my last post, I meant F-0 and F-1 tornadoes.

An F-2 tornado would be rather dangerous, but I believe tornadoes over F-1 intensity are rare during landfalling tropical cyclones.


The tornado that broke all the windows in the 30 floor buildings in downtown Ft Worth back in 2000 was an F-2.
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210. seabreeze97
5:36 PM GMT on July 24, 2007
leftovers,
to make a long story short...tell it to the neighbor who couldn't leave after the storm because of live electrical wires all over the place. He had to stay put with very little to survive on...Not to mention the absence of gasoline. A real mess...

So anyone who is talking the stay behind stuff is full of air...
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209. weatherguy03
1:55 PM EDT on July 24, 2007
Yep, very normal JP.
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207. EdMahmoud
5:49 PM GMT on July 24, 2007
I don't know why people keep acting like I recommended staying put for a Cat 1 on the coast. What I said, for most places, a Cat 1 or 2 will not do significant damage to a well built home, but if one were near the coast, leave anyway, because every now and then, and I gave the example of Charley, a Cat 2 can become a Cat 4 fairly quickly.


I will say, if one is 30 miles inland, spending hours in traffic fleeing a Cat 1 because it might spawn a tornado seems foolish, as, IIRC, Alicia spawned tornadoes as far inland as Tyler, TX, 200 miles inland, and, as the bus fire with multiple deaths during the Rita evacuation (from a nursing home 40 miles inland near Bellaire, TX) shows, at some point the risks of being on the highway surpass the risk that the generally weak F-1 or F-2 tornadoes that are most common in landfalling tropical cyclones, and will affect no more than a few hundred square years each, would pose.
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206. Chicklit
5:53 PM GMT on July 24, 2007

Why are dogs so scared of thunder?
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204. Weather456
5:46 PM GMT on July 24, 2007
Tropical Cyclone Report Subtropical Storm Andrea
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202. gthsii
5:38 PM GMT on July 24, 2007
hey tcc: you have a comment in your blog
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197. seabreeze97
5:29 PM GMT on July 24, 2007
EdMahmoud,
Even with the cat1 cat2, they all spin tornados.

And if the water don't get you, a tornado will.

Katrina spun tornados all up and down Mississippi. And from what I hear, It wiped out a million or so trees, damaged thousands of roof tops all the way up to Jackson...
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196. weatherguy03
1:33 PM EDT on July 24, 2007
Too much dust and too early. Nothing will form off the African coast anytime soon.
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194. seabreeze97
5:27 PM GMT on July 24, 2007
moonlightcowboy

you're right...some people never learn, or is it, some people tend to quickly forget.
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193. MTJax
5:14 PM GMT on July 24, 2007
IN BOTH THE 06Z/12Z NAM RUNS...A SMALL VORT/COLD LOW INITIATED BY
CONVECTION OVER THE YUCATAN DRIFTS NORTHWEST TWD THE NERN MEX/SRN
TX COAST THE NEXT FEW DAYS. COMPARED TO THE 00Z RUN...THIS SYSTEM
HAS TRENDED WEAKER AND SLOWER/FARTHER SOUTH. OWED TO THE WEAKER
NATURE OF THIS SYSTEM IN THE LASTEST RUNS...SFC PRESSURES FROM THE
CTRL TO THE NWRN GULF OF MEXICO ARE HIGHER COMPARED TO THOSE IN
THE 00Z NAM.

KIMBERLAIN

MODEL BIASES AT WWW.HPC.NCEP.NOAA.GOV
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192. hurricane23
1:08 PM EDT on July 24, 2007
Lots of convection of the african coast but no real organization in the near term as the SAL looks to keep things in check.
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191. Drakoen
5:04 PM GMT on July 24, 2007
Thanks...
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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.