Record Atlantic SSTs continue in the hurricane Main Development Region

By: Dr. Jeff Masters , 8:03 PM GMT on May 15, 2010

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Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes had their warmest April on record, according to an analysis of historical SST data from the UK Hadley Center. SST data goes back to 1850, though there is much missing data before 1910 and during WWI and WWII. The area between 10°N and 20°N, between the coast of Africa and Central America (20°W - 80°W), is called the Main Development Region (MDR) because virtually all African waves originate in this region. These African waves account for 85% of all Atlantic major hurricanes and 60% of all named storms. When SSTs in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.) SSTs in the Main Development Region (10°N to 20°N and 20°W to 85°W) were an eye-opening 1.46°C above average during April. This is the third straight record warm month, and the warmest anomaly measured for any month--by a remarkable 0.2°C. The previous record warmest anomalies for the Atlantic MDR were set in June 2005 and March 2010, at 1.26°C.


Figure 1. The departure of sea surface temperature (SST) from average for May 13, 2010. Image credit: NOAA/NESDIS.

What is responsible for the high SSTs?
As I explained in detail in a post on record February SSTs in the Atlantic, the Arctic Oscillation (AO) and its close cousin, the North Atlantic Oscillation (NAO), are largely to blame for the record SSTs. The AO and NAO are climate patterns in the North Atlantic Ocean related to fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores-Bermuda High. If the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), this creates a weak Azores-Bermuda High, which reduces the trade winds circulating around the High. During December - February, we had the most negative AO/NAO since records began in 1950, and this caused trade winds between Africa and the Lesser Antilles Islands in the hurricane Main Development Region to slow to 1 - 2 m/s (2.2 - 4.5 mph) below average. Slower trade winds mean less mixing of the surface waters with cooler waters down deep, plus less evaporational cooling of the surface water. As a result, the ocean heated up significantly, relative to normal, over the winter. Negative AO/NAO conditions have been dominant much of this spring as well, resulting in further anomalous heating of the MDR waters. This heating is superimposed on the very warm global SSTs we've been seeing over the past few decades due to global warming. Global and Northern Hemisphere SSTs were the 2nd warmest on record this past December, January, and February, the warmest on record in March, and will likely be classified as the warmest or second warmest on record for April, since NASA just classified April as the warmest April on record for the globe. We are also in the warm phase of a decades-long natural oscillation in Atlantic ocean temperatures called the Atlantic Multi-decadal Oscillation (AMO). This warm phase began in 1995, and has been partially responsible for the high levels of hurricane activity we've seen since 1995.

What does this imply for the coming hurricane season?
The high April SST anomaly does not bode well for the coming hurricane season. The three past seasons with record warm April SST anomalies all had abnormally high numbers of intense hurricanes. Past hurricane seasons that had high March SST anomalies include 1969 (0.90°C anomaly), 2005 (1.19°C anomaly), and 1958 (0.97°C anomaly). These three years had 5, 7, and 5 intense hurricanes, respectively. Just two intense hurricanes occur in an average year. The total averaged activity for the three seasons was 15 named storms, 11 hurricanes, and 6 intense hurricanes (an average hurricane season has 10, 6, and 2.) Both 1958 and 2005 saw neutral El Niño conditions, while 1969 had a weak El Niño.

The SSTs are already as warm as we normally see in July between Africa and the Caribbean, and we have a very July-like tropical wave approaching the Lesser Antilles Islands this weekend. However, wind shear is still seasonably high, and the tropical waves coming off of Africa are still too far south to have much of a chance of developing. The GFS model is indicating that shear will start to drop over the Caribbean the last week of May, so we may have to be on the watch for tropical storms forming in the Caribbean then.

For those of you interested in a more detailed look at the early season tropical weather outlook, consult the excellent wunderblogs of StormW and Weather456. I'll be back with a new post on Monday.

Jeff Masters

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Quoting MiamiHurricanes09:
Nevermind, I was informed by someone. Thanks either way.


That's cool, besides, every time I look at those model runs I have an acid flashback....LOL.
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Quoting wunderkidcayman:
hey guys check out the 12z GFS having our storm to have a twin A.K.A the Fujiwhara effect
look


G = ghost
F = forecast
S = system
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Thanks JRRP
Member Since: September 8, 2005 Posts: 0 Comments: 1385
Quoting taco2me61:

Hi Ya StormSurgeon Good to see ya on....
You staying dry today???

Taco :o)


Heeeeey Taco. Just jumped back in to mix a few days ago. Not raining at the moment here at Cottage Hill and Hillcrest but the t'storms are all around (as you know).
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Quoting StormSurgeon:


Just looked at it......showing no development.
Nevermind, I was informed by someone. Thanks either way.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
764. JRRP
[an error occurred while processing this directive]
Link
Member Since: August 16, 2007 Posts: 0 Comments: 5337
763. JRRP
Quoting MiamiHurricanes09:
Wow! 3 Tropical Stoms, that won't happen, lol.

lol yea
Member Since: August 16, 2007 Posts: 0 Comments: 5337
Quoting StormSurgeon:


Just looked at it......showing no development.

Hi Ya StormSurgeon Good to see ya on....
You staying dry today???

Taco :o)
Member Since: July 7, 2005 Posts: 6 Comments: 3237
Quoting wunderkidcayman:
hey guys check out the 12z GFS having our storm to have a twin A.K.A the Fujiwhara effect
look
Yeah I know, there are 3 TS in that picture. If that happens I will cut my ears off. Lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting MiamiHurricanes09:
Darn, I can't view the 12z GFS on my phone. What is it showing?


Just looked at it......showing no development.
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Quoting JRRP:

this is garbage imo
Wow! 3 Tropical Stoms, that won't happen, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
hey guys check out the 12z GFS having our storm to have a twin A.K.A the Fujiwhara effect
look
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Quoting pottery:

A shame, that. It's quite simple. For instance-
..the bowler runs in from somewhere around mid-off (to the right hander), and sends a return-swing delivery outside off-stump. The batsman attempts to meet it with a dead bat (!!), and is caught by a flying third-man, long and deep.
Simple really........

hahahahahahahahahahaha
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Quoting pottery:

Cricket. Aus vrs England. Final of the World 20/20 games. In Barbados.
No way I can explain, it would take years.......

Lol
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Darn, I can't view the 12z GFS on my phone. What is it showing?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting MiamiHurricanes09:
Oh, well I'm not interested. Lol.

A shame, that. It's quite simple. For instance-
..the bowler runs in from somewhere around mid-off (to the right hander), and sends a return-swing delivery outside off-stump. The batsman attempts to meet it with a dead bat (!!), and is caught by a flying third-man, long and deep.
Simple really........
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting IKE:
Thunderstorm at my house. 72 degrees outside.


Hello IKE. About the same here in Mobile.
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752. JRRP

this is garbage imo
Member Since: August 16, 2007 Posts: 0 Comments: 5337
Quoting pottery:

That's why I changed my post LOL.
Another wicket down. Aussie in BIG trouble.

Bigger trouble now, White is out.
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hey guys

MiamiHurricanes09 I think it is criket or what ever it is called

anyway I think that what the GFS is showing it right us guys over here will be watching that tropical wave but I could do with a TD or TS we will benefit from the rain that we need badly
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Quoting indianrivguy:


I think it's part of the mid Atlantic ridge system that also goes through Iceland..



North Atlantic Ridge or Atlantic Ridge, runs from Iceland then practically down the middle of the Atlantic to almost Antarctica, then around Cape Agulhas, South Africa, then up through the middle of the Indian Ocean then towards Egypt and the Mediterranean Sea.
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Quoting Weather456:
Hurricane Wilma in the Caribbean 2005



Ghost of seasons past. They just kept getting worse that year. I am so not looking forward to this one.
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Quoting KEEPEROFTHEGATE:
we can use 05 as a reference but to say 2010 is going to be greater than 05 just can not be stated for 2005 was a hyper season do i think 2010 will be active yes do i think it will out rank 05 maybe but its hard to forecast an all time record so all i can say is wait watch see and the best advice i can give anyone is be prepare have a plan and a backup plan hopefully the most we will see is 20 systems i figure that will be more than enough for everyone


I agree for sure.... 20 is enough and remember it only takes 1 for it to be a "Bad" Season.

Taco :o)
Member Since: July 7, 2005 Posts: 6 Comments: 3237
745. JRRP
Quoting stormhank:
anyone have a link of an eastern atlantic satelite which shows africa as well? thanks!!

Link
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744. IKE
12Z GFS through 228 hours...
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting stormwatcherCI:
I have been subjected to Cricket for the past 37 years and I still don't understand it. You definitely need more than 24 hours to explain it.

That's why I changed my post LOL.
Another wicket down. Aussie in BIG trouble.
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting stormwatcherCI:
Cricket.
Oh, well I'm not interested. Lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
741. IKE
Thunderstorm at my house. 72 degrees outside.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting pottery:

Cricket. Aus vrs England. Final of the World 20/20 games. In Barbados.
No way I can explain, in less than 24 hrs!
I have been subjected to Cricket for the past 37 years and I still don't understand it. You definitely need more than 24 hours to explain it.
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Quoting MiamiHurricanes09:
What is this game you and Aussie are playing?

Cricket. Aus vrs England. Final of the World 20/20 games. In Barbados.
No way I can explain, it would take years.......
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting MiamiHurricanes09:
What is this game you and Aussie are playing?
Cricket.
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Quoting pottery:
....need to go at 15/over to make a game I think. From here.
What is this game you and Aussie are playing?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
anyone have a link of an eastern atlantic satelite which shows africa as well? thanks!!
Member Since: September 8, 2005 Posts: 0 Comments: 1385
....need to go at 15/over to make a game I think. From here.
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting pottery:
...just starting to go now. Hussey!!

And White
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Quoting KEEPEROFTHEGATE:

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Hello everyone!

My internet is down so I am posting this through my phone. For the meantime I will be lurking. when I get my internet back I will resume posting.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
...just starting to go now. Hussey!!
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting pottery:
YUP!!

needing more luck now.
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Quoting KEEPEROFTHEGATE:
strange place for a shaker


I think it's part of the mid Atlantic ridge system that also goes through Iceland..
Member Since: September 23, 2006 Posts: 1 Comments: 2518
Hello all. Went to Dauphin Island yesterday to check on the activity. Double berms on the south side and a barrier on the north side (west end of the island). Walked about a half mile down the beach and didn't see any tar balls......thankfully.
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727. Skyepony (Mod)
92B gets a floater. Click pic for loop..
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Giant Plumes of Oil Forming Under the Gulf

......Scientists studying video of the gushing oil well have tentatively calculated that it could be flowing at a rate of 25,000 to 80,000 barrels of oil a day. The latter figure would be 3.4 million gallons a day. But the government, working from satellite images of the ocean surface, has calculated a flow rate of only 5,000 barrels a day.

BP has resisted entreaties from scientists that they be allowed to use sophisticated instruments at the ocean floor that would give a far more accurate picture of how much oil is really gushing from the well.

The answer is no to that,” a BP spokesman, Tom Mueller, said on Saturday. “We’re not going to take any extra efforts now to calculate flow there at this point. It’s not relevant to the response effort, and it might even detract from the response effort.” .....


Can you say CYA?
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Im normally on here during hurricane season and I thank you all for your input and giving me different links to use... Im no expert by no means but have been interested in hurricanes since the 1985 season when Elena and Kate affected me here in panhandle..So thank you all !! I have a feeling we're gonna have a busy season and will be on here around the clock..
Member Since: September 8, 2005 Posts: 0 Comments: 1385
strange place for a shaker
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Quoting hurricane23:
Don't buy the GFS...This model is notorious for developing ghost tc's every may.


Lets see if after the upgrade on June 22nd,it gets better.
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Quoting Patrap:
We never look to Africa for a wave to be anything..


Its only May 16th,

..only the Western Caribbean and GOM spit out systems this early.



It's never to early to wishcast.
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AOI

AOI

AOI

AOI
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Saw that LIVE last night in Bed..Laugh for 10 minutes after I bet.
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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.