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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491. Murko
12:39 AM GMT on July 25, 2007
Posted By: HIEXPRESS at 12:03 AM GMT on July 25, 2007.
...Now we add bigger drops (with a higher terminal velocity)...


Wouldn't larger drops have a lower terminal velocity, due to increased wind resistance?
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490. MrNiceville
12:30 AM GMT on July 25, 2007
What is it with those little convective blobs that pop off the YP into the BoC?

Is this what was bothering the NAM?

Looks like the shear forecast is for decrease in the SW GOM over the next 72 hours...

Lots of moisture down there...

Wave after wave terminating in the BoC...

Should we be interested in this activity?
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489. Patrap
7:40 PM CDT on July 24, 2007
Quickscat stuff for all Link
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488. sporteguy03
12:41 AM GMT on July 25, 2007
Photo Sharing and Video Hosting at Photobucket
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487. Patrap
7:39 PM CDT on July 24, 2007
GOES IR GOM loop Link
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485. Patrap
7:38 PM CDT on July 24, 2007
Signs of things a changing seems
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484. RL3AO
7:36 PM CDT on July 24, 2007
I haven't been following much all day. How is the CV wave looking?
483. CaicosRetiredSailor
8:33 PM EDT on July 24, 2007
SW
Thanks...... much swearing needed to get this pc to make one last post tonite
CRS ...off to the rumb locker
Member Since: July 12, 2007 Posts: 0 Comments: 6069
482. sporteguy03
12:36 AM GMT on July 25, 2007
Evening Patrap
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480. Patrap
7:35 PM CDT on July 24, 2007
Evening all..
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478. sporteguy03
12:31 AM GMT on July 25, 2007
JP,
Quicskat hit that area StormW, JP, Storm Junkie Interpolate?
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476. JLPR
12:27 AM GMT on Julio 25, 2007
wOoOo i spot my first little rotation
:D i hope it doesn't die to quickly
:D
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475. Tazmanian
5:23 PM PDT on July 24, 2007
whats the forcast mode forcasting today any thing new?
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474. CaicosRetiredSailor
8:25 PM EDT on July 24, 2007
SW, did you see my earlier question?

StormW

But, when preparing with the forecasts (this is from a power point presentation I have on Hurricane Charley), they recommend preparing for one category higher and landfall six hours sooner.


In that sentence, "they recommend preparing" who is the "they" and how is that recommendation promugated?

....I am involved with emergency mgmnt, and always looking for ways to raise the awareness of people here...

I am using backup pc this evening and may not be able to post easily, so do not be surprised if I don't reply quickly... I WILL be back.... soon if I can.
Thanks CRS
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472. sporteguy03
12:26 AM GMT on July 25, 2007
JP,
Time to ask Tom Terry what he thinks
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471. RL3AO
7:23 PM CDT on July 24, 2007
T numbers support a tropical storm from the remnants of Cosme. I guess we will see what the JMA and JWTC does with it.
468. KoritheMan
7:21 PM CDT on July 24, 2007
wow dalila sure looks better compared with
yesterdays appearance


I was thinking the same thing when I saw it at 55 mph a few minutes ago.
Member Since: March 7, 2007 Posts: 602 Comments: 21231
467. JLPR
12:16 AM GMT on Julio 25, 2007
wow dalila sure looks better compared with
yesterdays appearance
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466. GRDRATNAVARRE
12:11 AM GMT on July 25, 2007
HIEXPRESS - It's the inertia, total area and run off rate of the roof that would matter. I don't think that it would matter much if it were 1 inch per hour heavier rainfall as far as the roof goes. It's always the wind that gets the roof. If it finds a way under it will lift it. The extra down force of the rain would probably help to keep the roof on, but not much.
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464. sporteguy03
12:16 AM GMT on July 25, 2007
Tropical Wave development possible?
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463. CaicosRetiredSailor
8:14 PM EDT on July 24, 2007
good night all,
this pc is just making it too hard to stay on line
CRS
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462. Tazmanian
5:16 PM PDT on July 24, 2007
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 24 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 36W S OF 16N MOVING W AT 15 KT. THERE
IS A WELL DEFINED REGION OF LOW TO MID LEVEL CYCLONIC TURNING
NOTED FROM 10N-16N BETWEEN 30W-42W. DEEP CONVECTION IS MINIMAL
AND CONFINED TO THE ITCZ. SCATTERED MODERATE CONVECTION IS FROM
6N-9N BETWEEN 32W-40W.

TROPICAL WAVE IS ALONG 52W S OF 20N MOVING W 20-25 KT. A BROAD
INVERTED V SHAPE REMAINS EVIDENT IN THE SURROUNDING BROKEN
STRATOCUMULUS FIELD. NO DEEP CONVECTION IS FOUND. SCATTERED
SHOWERS ARE FROM 14N-20N BETWEEN 48W-55W...AND ALONG THE ITCZ
FROM 10N-12N BETWEEN 50W-56W.

CARIBBEAN TROPICAL WAVE IS ALONG 80W/81W S OF 20N MOVING W NEAR
20 KT. SOME CYCLONIC TURNING IS NOTED IN THE LOWER CLOUD FIELD
JUST S OF THE CAYMAN ISLANDS. SCATTERED MODERATE TO STRONG
CONVECTION IS ALONG THE COAST OF E CUBA FROM 18N-21N BETWEEN
76W-79W. SCATTERED SHOWERS ARE FROM 14N-18N BETWEEN 77W-85W.

TROPICAL WAVE IS OVER THE BAY OF CAMPECHE ALONG 95W/96W S OF 21N
MOVING W 10-15 KT. WIDELY SCATTERED MODERATE CONVECTION IS
INLAND OVER S MEXICO FROM 15N-17N BETWEEN 93W-97W. SCATTERED
SHOWERS REMAIN OVER THE BAY OF CAMPECHE FROM 18N-22N BETWEEN
91W-95W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N16W 10N40W 8N60W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS ALONG THE COAST OF W
AFRICA FROM 10N-14N BETWEEN 12W-18W. ISOLATED MODERATE
CONVECTION IS FROM 8N-14N BETWEEN 18W-30W. SCATTERED MODERATE
CONVECTION IS FROM 6N-9N BETWEEN 32W-40W.

...DISCUSSION...
GULF OF MEXICO...
A 1014 MB LOW IS CENTERED INLAND OVER SE LOUISIANA NEAR
31N90W. A SURFACE TROUGH EXTENDS W FROM THE LOW TO THE TEXAS
COAST ALONG 28N91W 28N96W. WIDELY SCATTERED MODERATE CONVECTION
IS FROM 26N-28N BETWEEN 87W-93W. ANOTHER SURFACE TROUGH
EXTENDS E FROM THE LOW TO FLORIDA NEAR 30N81W. CLUSTERS OF
WIDELY SCATTERED MODERATE CONVECTION ARE OVER THE NE GULF OF
MEXICO AND FLORIDA FROM 28N-32N BETWEEN 81W-88W. ELSEWHERE...
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE
INLAND OVER THE YUCATAN PENINSULA FROM 16N-21N BETWEEN 88W-91W.
SCATTERED MODERATE CONVECTION IS OVER S FLORIDA FROM 25N-28N
BETWEEN 79W-82W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS
CENTERED OVER CENTRAL TEXAS NEAR 31N99W PRODUCING DIFFLUENCE
WITH SCATTERED MODERATE CONVECTION OVER INLAND S TEXAS FROM
27N-30N BETWEEN 95W-100W. THE GULF OF MEXICO HAS MOSTLY SWLY
UPPER LEVEL FLOW WITH A CONSIDERABLE AMOUNT OF MOISTURE. EXPECT
AIRMASS THUNDERSTORMS THROUGHOUT THE GULF OF MEXICO AND
SURROUNDING LAND MASSES DURING THE NEXT 24 HOURS.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE CARIBBEAN SEA PRODUCING
CONVECTION. SEE ABOVE. THE PRESSURE GRADIENT OVER THE
CARIBBEAN SEA HAS SLACKENED THUS TRADEWINDS HAVE LIGHTENED.
15-20 KT WINDS REMAIN ALONG THE COAST OF N COLOMBIA HOWEVER.
OUTSIDE OF THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS
INLAND OVER HISPANIOLA FROM 18N-20N BETWEEN 70W-73W. ELSEWHERE
...SCATTERED MODERATE TO STRONG CONVECTION IS OVER N COLOMBIA
AND NW VENEZUELA FROM 9N-12N BETWEEN 70W-76W. SCATTERED
MODERATE CONVECTION IS INLAND OVER COSTA RICA AND NICARAGUA FROM
9N-13N BETWEEN 84W-87W. IN THE UPPER LEVELS...AN UPPER LEVEL
HIGH IS CENTERED NEAR THE CAYMAN ISLANDS AT 19N82W. EXPECT
CONTINUED CONVECTION OVER THE WRN CARIBBEAN SEA AND CENTRAL
AMERICA W OF 77W MOSTLY DUE TO THE TROPICAL WAVE DURING THE
NEXT 24 HOURS.

ATLANTIC OCEAN...
A SURFACE TROUGH IS OVER THE WRN ATLANTIC AND BAHAMAS ALONG
31N74W 25N79W. CLUSTERS OF WIDELY SCATTERED MODERATE CONVECTION
IS S OF THE TROUGH FROM 23N-30N BETWEEN 72W-78W. SCATTERED
MODERATE CONVECTION IS OVER S FLORIDA FROM 25N-28N BETWEEN
79W-82W. ONE DOMINATE 1028 MB HIGH IS OVER THE CENTRAL ATLANTIC
NEAR 37N44N PRODUCING MAINLY FAIR WEATHER. IN THE UPPER
LEVELS... A RIDGE IS OVER THE W ATLANTIC N OF 20N AND W OF 65W.
AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLANTIC NEAR
28N52W. AN UPPER LEVEL HIGH IS CENTERED FURTHER E NEAR 20N38W.
ANOTHER RIDGE IS OVER W AFRICA AND THE E ATLANTIC N OF 15N E OF
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461. AndyN
12:08 AM GMT on July 25, 2007
Great show on NOVA on Alabama Public Television about the Hurricane PAM exercise in NOLA and the days leading up to Katrina.
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460. HIEXPRESS
11:53 PM GMT on July 24, 2007
Dr. Masters:...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....

Any idea what this does to rainfall rates in tropical systems?

Say a building is designed to withstand Cat # winds horizontally, and the roof is designed to withstand a certain amount of load from wind & rain. Now we add bigger drops (with a higher terminal velocity) closer together & embed them in a downdraft (microburst). What is the velocity now? How much more energy does that all deliver Straight Down on to your roof? If it is a big, flat roof.... More than you planned for - It's toast.
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458. JLPR
12:01 AM GMT on Julio 25, 2007
lol yeah Chris passed north of me and it was so small all that i saw were one or two clouds
:D
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457. GRDRATNAVARRE
11:54 PM GMT on July 24, 2007
Hello all, good to see a few of the old timers here, SJ, Ike, StSimm, SW and the like. Been away for awhile, but lurking when I could till it started firing up. Looks like it's about too. It certainly appears the SAL is retreating in the face of all those waves. I think it's gonna be an interesting season.
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456. hurricaneman23
11:58 PM GMT on July 24, 2007
i remember last year with chris. some people were saying its gonna be a cat 3 and hit fla.
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455. JLPR
11:59 PM GMT on Julio 24, 2007
it looks kind of interesting and it can at least entertain us until something develops
lol :D
men i need something maybe a little depresion
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453. CaicosRetiredSailor
7:54 PM EDT on July 24, 2007
SJ
Thanks right back to you... I think that Safe and Well site is very much worth promoting, and making a part of ones individual plan... and let your relatives know that if all else fails, you will get a message posted there.
CRS
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452. StormJunkie
11:56 PM GMT on July 24, 2007
Just think it could use to get away from the ITCZ a little jp, not that it couldn't develop there. Although I still think development will be from something that is now E of 35.
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450. StormJunkie
11:55 PM GMT on July 24, 2007
Doing good, how's island life?
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448. StormJunkie
11:53 PM GMT on July 24, 2007
jl, I think it is more likely something would develop a little further E and N. If something were to start to develop around 8n it would have to break a little further away from the ITCZ by moving N some.
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446. HurrMichaelOrl
11:54 PM GMT on July 24, 2007
So July isn't actually less active than June, it just seems that way since we expect more storms as time goes by. Thanks for the correction.
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444. scwindsaloft
11:51 PM GMT on July 24, 2007
June averages .5 per month (named storms)
Link
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443. StormJunkie
11:50 PM GMT on July 24, 2007
Evening SSIG and CRS

Red Cross Safe and Well List now on the Quick Links page. Thanks CRS ☺

jp, 18z Ukmet still shows a system developing. It does appear the 18z GFS dropped it, but I would not be surprised to see it pick it back up on the 00z run.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
442. Dakster
11:36 PM GMT on July 24, 2007
It's hard to believe that ANY long time resident of the State of Florida is NOT prepared for Hurricane season. This has been driven into us year after year. Even with decades long inactivity and no TS hits. I remember preparing in Elementary school. I have a plan and so does my immediate family, I put my kit together every June and I use the supplies up (except candles) after Dec.1. We know where we are going and with who and how, where we will meet in case of total disaster, etc. etc...

Everyone by now should know that Hurricanes are UNPREDICTABLE in nature and have a tendency to all of a sudden change course and intensity, which is why there is a "cone of death/destruction" and not just a straight black line. Forecasters are good and amatuer forecasters here are good too, but the bottom line is NO ONE can predict a direct hit a day or two out with 100% accuracy and precision.

If you know of a new resident it is your civic duty to educate them of what can happen during a hurricane and to get prepared. Every area of the country has a potential natural disaster that you must prepare for. I have educated my neighbor who just moved here (miami, fl) from Nevada...

Not that us Miamians are the example to follow, since 1 hour after the storm there were lines miles long for ice, water, fuel, and food.... All of which we had stockpiled to last my family a week. My neighbors either left Florida or had the same provisions.

To blame TWC or the NEWS for YOU NOT BEING PREPARED is B.S. You should've been prepared by June 1. It doesn't cost you any more $$, because at the end of the season you use up your perishables to restock next year and the non-perishables you just keep on hand after initial investment. This costs less than a set of snow tires our nothern bretheren have to buy for thier cars. If a hurricane is dancing along the coast that you live off of, then you should have your shutters up (if you have them).

-- Off my soapbox --
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441. JLPR
11:50 PM GMT on Julio 24, 2007
hey guys what do u think?
if a little low were to develop around 35w 8n could it develop?
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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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