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 BahaHurican:
This is a very interesting hypothesis. I hope u are going to document as u go along - never know where that might lead research-wise. I for one would like to see what u find out. Certainly seems to bear out what we were saying earlier about N Antilles / Bahamas / FL tracks....


Yeah. What he said...
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Quoting KEEPEROFTHEGATE:
cchs for some reason haiti is a storm magnet and for sure one will get them if not more
I keep hoping that if this is going to be an anomalous year, it will be anomalous in that Haiti will not be hit by even one tropical system..... Just pray they stay east and west.....
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Quoting Weather456:


I have a hypothesis to test this year. that MSLP anomalies may also affect storm tracks. For example, a tropical cyclone would easier flow through a region of anomalous low pressures than anomalous high pressures. This and other variables help me propose that the Lesser Antilles, particularly the NE Caribbean is at highest risk this year. If you want to follow the pressure anomalies, it takes across the Greater Antilles and GOM.

Exclude the WCARIB because that is already a TC breeding ground.


I didn't know that was supposed to be something new. That seems like a basic forecasting technique to me. When I see that swath of low pressures on the European model, I think to myself that tracks will likely follow the middle to southern portion of the swath the most. The middle for the reason you mentioned, that the path of lowest pressure is the easiest and supports the most upward motion, and the southern part because that's where trade winds are reduced in the deep tropics supporting more formations and tracks in that area.
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Quoting KEEPEROFTHEGATE:
cchs for some reason haiti is a storm magnet and for sure one will get them if not more


Unfortunately so considering that they're pretty much located along several different typical paths that storms take during a hurricane season.
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Quoting TheCname:


Also notice the wetter than normal is in a cone from the Carb. into the Gulf Coast AL/FL panhandel. Maybe the model is trying to tell us where it thinks the "cone" will be this year or "the line of fire". The whole SE is wetter than normal on this model. Even the Carolinas/Virginia area. So I think this model is trying to tell us something.

I was thinking roughly the same thing. what else would cause a precip pattern like that? not saying it is right (and being in the bullseye this far out is always comforting, you know!) but it certainly is eye catching
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"E" has gone mad, look at this recent pic from 10:46PM CDT. The Mulakot web-cam is about 6 miles from the summit:
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Keep going with those upgrades, hopefully you won't need them this season.
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thank you, pottery. I appreciate that.

Ya'll behave- don't nobody go pokin' nobody with a stick, ya hear?

sleep and peace, friends
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Quoting Weather456:


I have a hypothesis to test this year. that MSLP anomalies may also affect storm tracks. For example, a tropical cyclone would easier flow through a region of anomalous low pressures than anomalous high pressures. This and other variables help me propose that the Lesser Antilles, particularly the NE Caribbean is at highest risk this year. If you want to follow the pressure anomalies, it takes across the Greater Antilles and GOM.

Exclude the WCARIB because that is already a TC breeding ground.
This is a very interesting hypothesis. I hope u are going to document as u go along - never know where that might lead research-wise. I for one would like to see what u find out. Certainly seems to bear out what we were saying earlier about N Antilles / Bahamas / FL tracks....

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Quoting pottery:

Sorry to seem uninterested. I am not.
This is pretty ghastly. But hopefully the stuff will sink again before it washes up somewhere. At least then, it wont be visible.
Oh Dear...

As much as I hate it for wildlife and fisheries, I have to think that is on the backburner for now. The stuff on top coming on our shores is top priority. Living in mobile right next to the stuff, I can tell you I fear for the safety of the people ... That stuff is toxic, of course.
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Quoting Stormchaser2007:
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:


Also notice the wetter than normal is in a cone from the Carb. into the Gulf Coast AL/FL panhandel. Maybe the model is trying to tell us where it thinks the "cone" will be this year or "the line of fire". The whole SE is wetter than normal on this model. Even the Carolinas/Virginia area. So I think this model is trying to tell us something.
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Quoting ftpiercecane:
Pottery a 160 years in your location has to say something about a well built house.

True. Not many left. It has been a maintenance challenge to me, for 23 years. Love it!
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Quoting cchsweatherman:
Given the record SSTs at the moment, now neutral ENSO conditions, and above normal moisture over Africa and the Atlantic, I don't see much stopping this upcoming hurricane season from being a very active and potentially devastating season. Considering all that Haiti has been through, I'm really praying for them more than anybody else this season to be spared since the picture painted by the long-range ECMWF and CFS looks quite ominous for the Caribbean region.
cchs for some reason haiti is a storm magnet and for sure one will get them if not more
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Quoting aquak9:
HouGalv...I've been trying tonite, but not getting any response.

Here goes:

NEW ORLEANS — The underwater plume of oil billowing from a renegade wellhead in the Gulf of Mexico is headed away from the coast and back out to sea, according to federally-funded scientists studying the spill.

In the first on-site measurements of the oil spreading below the surface, researchers found the plume of crude stretches 15 to 20 miles southwest from the site of the damaged wellhead and is about 5 miles wide, said Vernon Asper, a University of Southern Mississippi marine scientist leading the research.

The plume is compact, much thicker than the lighter remnants reaching the surface and suspended in about 3,000 feet of ocean, he said. A deepwater current is dragging it out to sea. The underwater oil cloud is not connected to the surface slick — now the size of Delaware and Rhode Island combined.

"This [underwater] plume is some of the heavier products of the oil that won't reach the surface," Asper said in a radio-telephone interview from aboard the R/V Pelican, a 116-foot research ship at the site of the spill. "We think this oil is going to stay down there. It doesn't look like it's coming to the surface."


Sorry to seem uninterested. I am not.
This is pretty ghastly. But hopefully the stuff will sink again before it washes up somewhere. At least then, it wont be visible.
Oh Dear...
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Quoting altesticstorm10:
To me 2007 was the year of the coulda shoulda woulda wannabe storm that never happened/unfortunate little invest that died a merciless little death. I'll never forget...that first "93L" (near Africa) "96L" (in the CATL) and "99L" (in the CATL and then Caribbean)...there was a "96L" behind Felix and a "97L" in the Caribbean later that year that everyone hyped to death that never developed...was the story of the season to me. To me many storms that should have developed which would have led to a hyperactive 2007 season didn't form because of the dry air and dust in the CATL due to the strong subtropical ridge which enforced trade winds and dry air (and steered Dean/Felix south, south and more south) and the strong La Nina which cooled the water temps a small bit. 2007 was the least efficient year ever for tropical entities.


2007's La Nina was offset by the effects of a +NAO.

Still the it was able to spit out 15 named storms.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
402. Skyepony (Mod)
The ripe conditions in the Arabian Sea is only fueling the wave train. That is 93A on the right. Most likely a wave stepping off on the left.

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Pottery a 160 years in your location has to say something about a well built house.
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Given the record SSTs at the moment, now neutral ENSO conditions, and above normal moisture over Africa and the Atlantic, I don't see much stopping this upcoming hurricane season from being a very active and potentially devastating season. Considering all that Haiti has been through, I'm really praying for them more than anybody else this season to be spared since the picture painted by the long-range ECMWF and CFS looks quite ominous for the Caribbean region.
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SRQfl- post 392- you can't post guns here or you'll get banned. Please remove the post or face the wrath of Admin!
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SRQfl that post could cause ya to be banned with a picture of a weapon in it if ya don't want to become empty space ya might want to take it down

but it may be too late already
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HouGalv...I've been trying tonite, but not getting any response.

Here goes:

NEW ORLEANS — The underwater plume of oil billowing from a renegade wellhead in the Gulf of Mexico is headed away from the coast and back out to sea, according to federally-funded scientists studying the spill.

In the first on-site measurements of the oil spreading below the surface, researchers found the plume of crude stretches 15 to 20 miles southwest from the site of the damaged wellhead and is about 5 miles wide, said Vernon Asper, a University of Southern Mississippi marine scientist leading the research.

The plume is compact, much thicker than the lighter remnants reaching the surface and suspended in about 3,000 feet of ocean, he said. A deepwater current is dragging it out to sea. The underwater oil cloud is not connected to the surface slick — now the size of Delaware and Rhode Island combined.

"This [underwater] plume is some of the heavier products of the oil that won't reach the surface," Asper said in a radio-telephone interview from aboard the R/V Pelican, a 116-foot research ship at the site of the spill. "We think this oil is going to stay down there. It doesn't look like it's coming to the surface."

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Quoting Stormchaser2007:
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:
Geez. That precipitation forecast map looks like the two major track patterns one would expect in a neutral season....
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Quoting BahaHurican:
So in the final analysis track matters as much as anything. If 2005 was good for nothing else, I'm convinced it was the catalyst for the improved forecasts of 2007 onward. We're still looking for intensity accuracy, but track accuracy, and early confidence in that accuracy, is going to be key to minimizing loss of life and damage to property in affected areas.

I wish I could feel there would be no affected areas this year.... :o(


I have a hypothesis to test this year. that MSLP anomalies may also affect storm tracks. For example, a tropical cyclone would easier flow through a region of anomalous low pressures than anomalous high pressures. This and other variables help me propose that the Lesser Antilles, particularly the NE Caribbean is at highest risk this year. If you want to follow the pressure anomalies, it takes across the Greater Antilles and GOM.

Exclude the WCARIB because that is already a TC breeding ground.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting altesticstorm10:
Hey, Fred finally found Wilma...in the Atlantic after 4 long years they were reunited. So anything can happen. And I predict at least 2-3 significant hurricanes impacting the Lesser Antilles where you live my friend. Evacuate when they tell you...
Gee, Thanks LOL.
Dam thing is, I live on the top of a small ridge. West of me is flat land to the sea (6 miles). Any storm passing just North of here is going to give me westerly wind.
I have no wind protection, and live in a 2 storey house, made of wood, 160 years old.
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If this doesn't make you angry, then I don't know what could, but this is just disgusting:
Scientists find giant oil plumes under Gulf
One is about 10 miles long, 3 miles wide and 300 feet thick
---and heres the link to read the article:
http://www.msnbc.msn.com/id/37171468/ns/us_news-the_new_york_times/
I was so angry after reading this, I coulda spit fire. Guess it's the feeling of helplessness that makes me so D&%NED angry!
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Quoting pottery:

Seems to me, that just about every post around here keeps adding fuel to the fire. You notice that?


lol

Yeah it does seem that way.
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Quoting Weather456:
La Nina generated storm numbers in 1995, while SSTs were found to be the main generator of 2005, all other conditions equal.

There is a 35% chance that La Nina develops this summer which would prove disastrous.

But why storm numbers?

2005 had nearly twice as much storms as 2004 and 2008, yet all three years prove to be disastrous. Fatalities in 2004 and 2005 both exceeded 3000 lives while Mitch of 1998 was very deadly.

So in the final analysis track matters as much as anything. If 2005 was good for nothing else, I'm convinced it was the catalyst for the improved forecasts of 2007 onward. We're still looking for intensity accuracy, but track accuracy, and early confidence in that accuracy, is going to be key to minimizing loss of life and damage to property in affected areas.

I wish I could feel there would be no affected areas this year.... :o(
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Quoting Stormchaser2007:
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:


that 2.5 millibar anomaly in the Gulf is significant since tropical cyclones find it easier to deepen in an environment where pressures are below the climatological mean. That anomaly equals major hurricanes.
Member Since: July 24, 2005 Posts: 407 Comments: 19076


latest nw atl.basin WV image
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Quoting KEEPEROFTHEGATE:
later MH09
Later.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting altesticstorm10:

And then you'll be sleeping most the day missing some of the real fun as my circadian cycle was in shambles all 2005 summer/autumn. I'd usually fall asleep downstairs in the tent with the weather channel on.
LOL
Quoting Stormchaser2007:
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:
That's pretty freaky, especially all that precipitation over SFLA.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Stormchaser2007:
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:

Seems to me, that just about every post around here keeps adding fuel to the fire. You notice that?
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later MH09
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Well I'm off to bed. I'll see you all tomorrow. Good Night and God bless!
Member Since: September 2, 2009 Posts: 130 Comments: 21091
I found this interesting and somewhat disturbing.

CFS
August MSLP Anomaly forecast:



August Precip Anomaly forecast:
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LOLOLOL--Hurricane Walter!!
I would never be able to take a "Walter" storm seriously.
What a HOOT!
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Quoting KEEPEROFTHEGATE:
i got a funny feeling the blogs will be far from dead from here till about early oct
Me too, but I'm thinking more towards November. And you know I'll be up the entire night when there are major hurricanes roaming.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Do not want any 2004 tracks here in Florida and I hope Haiti can some how avoid the bad season coming. God bless them.
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Quoting BahaHurican:
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....

Another great analysis.
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Quoting MiamiHurricanes09:
Yeah and it's 11:15 PM, you would think the blog would be dead.
C'mon, it's May 15th. AEW season is open.... lol
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La Nina generated storm numbers in 1995, while SSTs were found to be the main generator of 2005, all other conditions equal.

There is a 35% chance that La Nina develops this summer which would prove disastrous.

But why storm numbers?

2005 had nearly twice as much storms as 2004 and 2008, yet all three years prove to be disastrous. Fatalities in 2004 and 2005 both exceeded 3000 lives while Mitch of 1998 was very deadly.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting pottery:
...and in the meantime, the wave east of here just cannot get past the wind-wall.
Plus, it's losing convection.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
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
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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.