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:
Yeah and it's 11:15 PM, you would think the blog would be dead.
i got a funny feeling the blogs will be far from dead from here till about early oct
Member Since: July 15, 2006 Posts: 169 Comments: 53296
...and in the meantime, the wave east of here just cannot get past the wind-wall.
Plus, it's losing convection.
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting Weather456:


correct.

Remember a normal season, above average season, below average season, 2005 being anomaly, 2009 being inactive...all this is based on 160 years of records and understanding and hurricanes were recorded as far back as the days of Columbus.

We we do a forecast and we say well above average...we are going on the basis of what we know...10 named storms.

I think this was why forecasters and general public alike were taken so off guard by 2005. It was so genuinely unprecedented. [I can't IMAGINE what forecasters in 1933 were thinking - end of the world? LOL] With 05 in recent memory, we aren't as likely to be shocked with well above average numbers, especially since we have a precedent now on which to base our expectations. IOW, we have a data set which describes conditions under which the ATL is likely to produce 25+ named storms. To be honest, I can't think of anything right now, if conditions are as favorable as we expect, to prevent pottery's 41 storms from forming. Problem is, I can't think of what WOULD cause them to form, either....
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365. xcool
EAST PACIFIC HURRICANE SEASON BEGINS TODAY- AND ALL IS QUIET

May 15 is the official beginning to the east Pacific hurricane season. Conditions are typically a little more favorable on that side of Central America at this time of year, thus the two week head start on the Atlantic Basin. The NHC reports that there are an average of 15 named storms in the east Pacific each year with nine of them becoming hurricanes. We might see four major (category 3 or higher) hurricanes form in this region, depending on how busy the Atlantic is.

Most east Pacific hurricanes will form and track westward towards the cooler waters of the open ocean, well away from Mexico and Central America. Some, however, will get caught by a weakness in the large high pressure that reigns over the eastern North Pacific and turn northward in to land. The resort areas of Mexico, including the Baja Peninsula, are at risk of being hit by hurricanes, sometimes intense ones, in any year. As with the Atlantic, there is no way to know with any degree of certainty how much risk there is for a specific area.

I will post regular updates on any development potential for the east Pacific and will link to tracking maps when there is a named storm. Also, beginning May 31 with the new Weekly Hurricane Outlook video broadcast, I will provide a more detailed discussion for that region. Anyone with vacation, fishing or diving plans along the west coast of Mexico up through the Baja will want to keep up with the latest info. That being said, there is no indication of any tropical storm formation in the east Pacific in the near future. I would not expect to see development until probably the last week of May when a more favorable upward motion pattern emerges. I'll have more here on Monday


by Mark Sudduth
Member Since: September 26, 2009 Posts: 2 Comments: 15625


15 days remain
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting KEEPEROFTHEGATE:
good info on the blogs tonight

got a good crowd here

Yeah, this is good stuff.
Thanks to all...
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting KEEPEROFTHEGATE:
good info on the blogs tonight

got a good crowd here
Yeah and it's 11:15 PM, you would think the blog would be dead.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting altesticstorm10:

Very true but DEFINITELY not track wise. 1995 was out to sea
Absolutely not, I'm thinking more 1964/2004 hurricane tracks.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
good info on the blogs tonight

got a good crowd here
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting altesticstorm10:
100% chance of an above-average season. One doesn't have to do much to get 11 freaken' named storms and 6 hurricanes.

80% chance of a well-above average season (2004, 2008 range)

50% chance of a HYPER active season (1995, 1933 range)

15% chance of a SUPER HYPER ACTIVE season (Greek letters, dragon territory, 2005, etc).

it's never 100%. all it would take was a nuclear war, massive volcanic eruption, big meteorite .... any number of unlikely, but possible things from the crazy to the mundane.
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Quoting Weather456:


Hit the nail on the head. And when we say experiment, we cannot use 2005 since that is one year. We would have to use years where SSTs were at this level and how do we do that when 2010 has the highest? All other selected years will fall short.

Probabilities may help solve the problem but it seems there is a 80% of an above average season.

I agree, I havent put much thought into real probability here, and you are probably right in suggesting 80% above average (or greater given the analogs that we do have, even tossing out outliers) the numbers I gave were an illustration. I think what we need to do is just know the possibility of a hyper season is on the table. In many years the odds of that are below 5%, to say it could approach .. 20%?? should be enough to put the fear in anyone, even if a "forecast" calls for a significantly lesser number
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"The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given."


naaaahhhh...y'think?
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Quoting altesticstorm10:
100% chance of an above-average season. One doesn't have to do much to get 11 freaken' named storms and 6 hurricanes.

80% chance of a well-above average season

50% chance of a HYPER active season (1995, 1993 range)

15% chance of a SUPER HYPER ACTIVE season (Greek letters, dragon territory, 2005, etc).
I think 1995 is the best analog season, named storm wise.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting BahaHurican:
I think 20 is about the outside of what most wx scientists would reasonably expect. I also think we [general public, bloggers] wouldn't even be thinking 20 if we didn't have 2005 in our recent memory. And with good reason, imo. How many seasons, before or after 1950, have exceeded that 20 storm "limit"? To forecast 25 or 30, wouldn't one need to have a greater statistical basis?


correct.

Remember a normal season, above average season, below average season, 2005 being anomaly, 2009 being inactive...all this is based on 160 years of records and understanding and hurricanes were recorded as far back as the days of Columbus.

When we do a forecast and we say well above average...we are going on the basis of what we know...10 named storms.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
in order for 2010 to beat 2005 it would have to have 33 named systems before dec 31
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting Stormchaser2007:


Man Im glad that ECM is freeing up some of their products to the public. The ECMWF (and its ensembles) have been pretty good this year and it looks like we'll need them a lot for this upcoming Hurricane season.

Thanks for the links Adrian!


Hey no problem... 850mb T and anomalies have also been added to the regular site which is also great. graphics will now be out to 240 regularly.
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350. xcool
hey Adrian!
Member Since: September 26, 2009 Posts: 2 Comments: 15625
Quoting lickitysplit:
NYT:

Scientists Find Giant Plumes of Oil Forming Under the Gulf

"Scientists are finding enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick. The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given."


That is REALLY scary. But I was wondering about that today when I was looking at Gulf currents.
The currents are so mixed up in there, and there are currents and counter-currents and the dam place where the oil is leaking is nearly a MILE deep.
There are bound to be oil-layers moving around under there.
Maybe not as much as that quote said, but who knows?
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting BahaHurican:
I think 20 is about the outside of what most wx scientists would reasonably expect. I also think we [general public, bloggers] wouldn't even be thinking 20 if we didn't have 2005 in our recent memory. And with good reason, imo. How many seasons, before or after 1950, have exceeded that 20 storm "limit"? To forecast 25 or 30, wouldn't one need to have a greater statistical basis?


these are the numbers i believe could be possible

TOTAL STORMS 21 TO 23
TOTAL HURRICANES 11 TO 14
TOTAL MAJORS 5 TO 7
TOTAL CAT 5's 1 TO 3
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting SouthALWX:
456, basically you are saying the science can't quantify the data without a previous "experiment" with very similar conditions? If that's so then I agree 100%. On the other hand, If we were to pose the question in probability form, I feel a greater percentage of possible outcomes has to be estimated at super hyper active than super sub-active would you not agree?

Let's try this:
super sub active 5%
below average 10%
average 20%
above average 50%
super hyper active 15%


Hit the nail on the head. And when we say experiment, we cannot use 2005 since that is one year. We would have to use years where SSTs were at this level and how do we do that when 2010 has the highest? All other selected years will fall short.

Probabilities may help solve the problem but it seems there is a 80% of an above average season.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting hurricane23:
Almost forgot see THIS.


Man Im glad that ECM is freeing up some of their products to the public. The ECMWF (and its ensembles) have been pretty good this year and it looks like we'll need them a lot for this upcoming Hurricane season.

Thanks for the links Adrian!
Member Since: June 9, 2007 Posts: 4 Comments: 15790
Quoting Weather456:


As Baha rightfully said, I cannot conceptualized such numbers. That is super hyper active. Our limit of understand is the hurricane season of 1933. 2005 to us is an anomaly. We are not saying that we cannot have 25+ storms, but how do you make a forecast for such numbers? thats the big question.

I think 20 is about the outside of what most wx scientists would reasonably expect. I also think we [general public, bloggers] wouldn't even be thinking 20 if we didn't have 2005 in our recent memory. And with good reason, imo. How many seasons, before or after 1950, have exceeded that 20 storm "limit"? To forecast 25 or 30, wouldn't one need to have a greater statistical basis?
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Almost forgot see THIS.
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Quoting BahaHurican:
This is my big concern. I think Haiti symbolizes for us the very real concern the entire Caribbean basin should have this season. While our individual situations are not as dire as Haiti's in a literal sense, metaphorically we are all as vulnerable to the aftermath of a hurricane, especially a major hurricane, or, even worse, a series of hurricanes. Economies which are already very fragile because of the economic "earthquake" of the recession may very well go under if forced to endure the negative effects on tourism and agriculture typically associated with a hurricane strike...

And that, is the reality of the thing.
Very Well said, Baha.
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting hurricane23:
Doesn't get any better then this.


I love Allan Huffman's site. Thats the only site I use now for accessing computer models since his site offers pretty much all the models available and so many different products from each model. Now with the ECMWF images, its gonna be even better. I like to call it one stop model surfing.
Member Since: Posts: Comments:
456, basically you are saying the science can't quantify the data without a previous "experiment" with very similar conditions? If that's so then I agree 100%. On the other hand, If we were to pose the question in probability form, I feel a greater percentage of possible outcomes has to be estimated at super hyper active than super sub-active would you not agree?

Let's try this:
super sub active 5%
below average 10%
average 20%
above average 50%
super hyper active 15%
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Quoting aquak9:


stormchaser, I believe it's already there, just not visibly, errr, on the surface.

this is a short article but I'd love some intelligent points of view here.

Link


still hoping for a comment? could this be correct?
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For example, on May 16 2005, NOAA predicted 12–15 named storms with full understanding that SSTs were near record levels. At this point, 1933 was the most active, followed by 1995. Because of our understanding at the time of normal and above normal seasons, we could not foresee 28 named storms.

It is the same with 2010.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


As Baha rightfully said, I cannot conceptualized such numbers. That is super hyper active. Our limit of understand is the hurricane season of 1933. 2005 to us is an anomaly. We are not saying that we cannot have 25+ storms, but how do you make a forecast for such numbers? thats the big question.


Thanks.. Understood.
I am still going with my 19 for the season (total storms)
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Doesn't get any better then this.
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Quoting Weather456:


As Baha rightfully said, I cannot conceptualized such numbers. That is super hyper active. Our limit of understand is the hurricane season of 1933. 2005 to us is an anomaly. We are not saying that we cannot have 25+ storms, but how do you make a forecast for such numbers? thats the big question.

I believe 1933 had far more hurricanes than 2005 because back then they didn't have the technology to go east of 50˚W.

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Weather456:
The most we can do at this point is pray and hope that by season ends we all come out with a sign of relief and thankfulness. Caribbean economies will suffer if forecasts verify and I dont think that would help haiti rebuilding efforts and people who are still trying to stand on their feet after 2004, 2005, 2007, and 2008.

This is my big concern. I think Haiti symbolizes for us the very real concern the entire Caribbean basin should have this season. While our individual situations are not as dire as Haiti's in a literal sense, metaphorically we are all as vulnerable to the aftermath of a hurricane, especially a major hurricane, or, even worse, a series of hurricanes. Economies which are already very fragile because of the economic "earthquake" of the recession may very well go under if forced to endure the negative effects on tourism and agriculture typically associated with a hurricane strike...
Member Since: Posts: Comments:
NYT:

Scientists Find Giant Plumes of Oil Forming Under the Gulf

"Scientists are finding enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick. The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given."

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I'm probably in the extreme minority here, but I don't see any real use for numerical predictions before any hurricane season since numbers, at least in my opinion, don't matter when it comes to evaluating a hurricane season. The most important things when it comes to hurricane season are when and where storms make landfall and what impact do they have on those areas. Sure numbers may show that a hurricane season has above average activity, but in the end, its the toll on life that really counts.
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Quoting Weather456:
The most we can do at this point is pray and hope that by season ends we all come out with a sign of relief and thankfulness. Caribbean economies will suffer if forecasts verify and I dont think that would help haiti rebuilding efforts and people who are still trying to stand on their feet after 2004, 2005, 2007, and 2008.


A big AMEN to that.
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting pottery:

But the reality is, there were more than 30 storms in the Atl. in 2005.
What is the problem with 40?


As Baha rightfully said, I cannot conceptualized such numbers. That is super hyper active. Our limit of understand is the hurricane season of 1933. 2005 to us is an anomaly. We are not saying that we cannot have 25+ storms, but how do you make a forecast for such numbers? thats the big question.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting pottery:

Interesting. On what basis are you saying that 2010 will be lower than 2005?
What existed in 05 that caused the high numbers, that dont exist now?
there is always a possiblity i guess it can exceed 05 season but i hesitate in calling that because

The 2005 Atlantic hurricane season was the most active Atlantic hurricane season in recorded history

and hopefully 2010 don't have in its mind to become the greatest season ever cause if it does then it will be an all time record just like the infamous 2005 season
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting StormChaser81:
Getting very close to the Loop Current.


stormchaser, I believe it's already there, just not visibly, errr, on the surface.

this is a short article but I'd love some intelligent points of view here.

Link
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Quoting wunderkidcayman:
hey guy's can you get me all the info of the "E" volcaino because my sister is coming from the UK tomrrow evening please I have not see her in over a few years


It's going to be close. Like Bord said, they need to call the airline.

Officials have warned the ash from volcanic eruptions in Iceland could disrupt air travel in both Britain and Germany in the next few days.

The British Department of Transport on Saturday stated a possible closure of parts of British airspace on the weekend, saying those problems could persist through Tuesday.

The department said different parts of British airspace could close at different times in the next few days, which would include England's southeast -- home to Europe's busiest airport at Heathrow as well as Gatwick, Stansted and other major airports.
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This model is warming things up really quickly.

Current


72 hours
Member Since: September 2, 2009 Posts: 130 Comments: 21091
The most we can do at this point is pray and hope that by season ends we all come out with a sign of relief and thankfulness. Caribbean economies will suffer if forecasts verify and I dont think that would help haiti rebuilding efforts and people who are still trying to stand on their feet after 2004, 2005, 2007, and 2008.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:
Also remember that most forecasters predict around 15-18 named storms. What is interesting is that all other conditions resemble 2005 but because we see 2005 as an anomaly I believe most of these numbers were under constraint. We cannot go beyond a certain limit because of our understanding. These numbers appear to be the limit of said understanding.


Very well stated there man.
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Quoting Weather456:
Also remember that most forecasters predict around 15-18 named storms. What is interesting is that all other conditions resemble 2005 but because we see 2005 as an anomaly I believe most of these numbers were under constraint. We cannot go beyond a certain limit because of our understanding. These numbers appear to be the limit of said understanding.

But the reality is, there were more than 30 storms in the Atl. in 2005.
What is the problem with 40?
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Quoting BahaHurican:
I think we have a hard time conceptualizing that much energy in the ATL. Nobody bats an eye at 25 storms in the WPac....

Very good point.
Member Since: October 24, 2005 Posts: 0 Comments: 24059
Post 315. OK, I think you answered me there.
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Quoting pottery:

Interesting. On what basis are you saying that 2010 will be lower than 2005?
What existed in 05 that caused the high numbers, that dont exist now?


See post 315
Member Since: July 24, 2005 Posts: 407 Comments: 19076
I think we have a hard time conceptualizing that much energy in the ATL. Nobody bats an eye at 25 storms in the WPac....
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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.