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 tramp96:
basically yes but we still have to account for the timing of other features that affect steering.

Levi talked about high pressure parking near Hudson Bay. Is that something that is similar to the high that parks over Texas every year and if so what are the consequences?


I know I heard him talked about that. The high that parks over Texas is called a continental ridge and forms from the expansion of heat over the summer landscape. It is tied to the North American Monsoon but that is a story in its self. The high that parks over Texas sometimes protect the state from tropical cyclones.

It has found that anomalous high heights over Eastern Canada during the peak of hurricane season creates a blocking pattern for mid-latitude storms to the north which help recurve cyclones and help steer cyclones into the CONUS from the south.


Unfavorable Years - focus on Eastern Canada

2005



2004



2008



Favorable Years

2006



2009



1998





Member Since: July 24, 2005 Posts: 407 Comments: 19076
Good Afternoon!
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I understand why now 2005 and 2010 are so similar.. 2005 had every single ingredient come together for an insane season.. 2010 has followed the same footprints. Same TCHP, SSTs, dying (now dead) El Nino, same amount of tornadoes in the US, negative NAO. To boot, we have something that if 2005 had, would have been way worse, low dust in the Atlantic.
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Quoting gordydunnot:
Out for awhile. All I can say is that is one helluva wave for this time of year coming at you Pottery. Thank God for the shear.

Yeah. It's Shear Madness.
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Thank you Dr Masters,

That is scary stuff; so funny, our local waters were so much colder than normal due to record breaking cold for Florida, but the tropical Atlantic never got any of that cold weather like we did.. and our water is warming up quickly.

Hi everyone,

appears it is going to be a very busy season so I am sure I will be checking in regularly in a few short weeks.

so until them, enjoy your weekend,

Gams

Oh I officially predicted the first Hurricane will be declared on June 21st (not tropical storm but declared hurricane).. I just hope it is a fish storm.


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Out for awhile. All I can say is that is one helluva wave for this time of year coming at you Pottery. Thank God for the shear.
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The wave is definitely looking more organized than earlier and convection seems to be increasing.
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Quoting gordydunnot:
Hey Pottery the sci/fi channel has a name that movie contest. I detect a winner. 6 Month Mega Cane has a nice ring to it.

Sounds good!
Dont mind me. I am just Hyper-Casting here.
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Quoting GainesvilleGator:
Dr. Masters blogged a few weeks ago that we would get a late start for the 2010 Hurricane Season due to lingering affects of El Nino. He should be making his seasonal forecast within the next two weeks. With the El Nino falling off the cliff in recent weeks, I wonder if he will reverse his late start prediction.


When he made that statement, the shear forecast called for below average shear across much of the Atlantic come season. Right now shear is below average across the basin.
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Hey Pottery the sci/fi channel has a name that movie contest. I detect a winner. 6 Month Mega Cane has a nice ring to it.
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basically yes but we still have to account for the timing of other features that affect steering.

Levi talked about high pressure parking near Hudson Bay. Is that something that is similar to the high that parks over Texas every year and if so what are the consequences?
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Quoting stormwatcherCI:
Not funny. LOL But coming from Africa would have to cross T & T first, right Pottery ?

OOOOPS! I had not thought of that......
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All is good here, gambler.
Sunny, breezy, cool, real nice.
Expecting some rain though.
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I knew what you meant Weather. Like I said "just had to be asked"
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Quoting hurricanejunky:
Cyclone Oz is broadcasting live from Lake Leon, TX and getting ready for a nasty cell heading his way.
Not any more; He gave up and went Off The Air
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Quoting GainesvilleGator:
Dr. Masters blogged a few weeks ago that we would get a late start for the 2010 Hurricane Season due to lingering affects of El Nino. He should be making his seasonal forecast within the next two weeks. With the El Nino falling off the cliff in recent weeks, I wonder if he will reverse his late start prediction.


There are so many things that mix together to create a storm or destory it. While all systems are go for the 2010 hurricane season, there is still no guarantee it will start early

I do feel it will, but there is always a chance we go through a June without a storm
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Quoting pottery:

Sounds about right, for Grand Cayman.
(sorry, irresistable, that one)
Not funny. LOL But coming from Africa would have to cross T & T first, right Pottery ?
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Quoting msgambler:
Good eveing Weather456. The question must be asked!!!!! Favorable for whom? LOL


depends on how you look at....

looks good from a tropical cyclone points of view
looks bad on our point of view
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Good evening Ike, pottery, stormpatrol, Skye. Hope all are well this evening.
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Quoting tramp96:

Does this graphic mean that hurricanes will be steered toward the conus


basically yes but we still have to account for the timing of other features that affect steering.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting pottery:

Sounds about right, for Grand Cayman.
(sorry, irresistable, that one)

LMAO!! Its ok we're in the line of fire most years anyway even if not a direct hit, at least with most hurricanes you have time to be prepared, if we had not been prepared for Ivan 04 I think our official lost of life would have been alot more than 2-3!
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Good eveing Weather456. The question must be asked!!!!! Favorable for whom? LOL
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Quoting Hurricanes101:


2009 being so quiet allowed for the SSTs to jump to record heights. Also the timing of the El Nino dying out could not be any worse


I am still rather in disbelief that we have reached a year hotter than 2005, and so soon.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Dr. Masters blogged a few weeks ago that we would get a late start for the 2010 Hurricane Season due to lingering affects of El Nino. He should be making his seasonal forecast within the next two weeks. With the El Nino falling off the cliff in recent weeks, I wonder if he will reverse his late start prediction.
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44. IKE
The first storm in 2005 formed on June 8th....

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Quoting Weather456:
Thanks for the acknowledgement Dr. Masters.

In other news...this is the type of high we might be seeing often this hurricane season



Does this graphic mean that hurricanes will be steered toward the conus
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Quoting stormpetrol:
37. Weather456, Thanks for the explanation much appreciated!


The other part to the question is that yes....the tracks based on the nature of the NAO takes the system into the most favorable areas.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:
Now we wished that 2009 had not been so quiet as it was. Conditions this year are not good, they are exceptionally good.


2009 being so quiet allowed for the SSTs to jump to record heights. Also the timing of the El Nino dying out could not be any worse
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37. Weather456, Thanks for the explanation much appreciated!
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Now we wished that 2009 had not been so quiet as it was. Conditions this year are not good, they are exceptionally good.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting stormpetrol:
Still sticking with 19 named storms 9 hurricanes and 6 majors with 2 becoming possible cat5s

Sounds about right, for Grand Cayman.
(sorry, irresistable, that one)
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Quoting stormpetrol:

Would that mean that the Caribbean, Central America, Mexico and Gulf coast states are probably at higher risks this season due to southerly and westerly tracks?


The favorable conditions this year are widespread, low than normal pressures, high ssts and wetter conditions are expected basically across the Western Atlantic. The only region that maybe missing some of these conditions is the GOM north of 25N but that is irrelevant since storms don't normally form there, they move there.

MSLP Anomalies - cover basically the entire Western Atlantic



Same as precip



and SSTs



So basically everyone is at risk this season but because the lesser Antilles are the deepest areas in the tropics, they have the highest risk

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Still sticking with 19 named storms 9 hurricanes and 6 majors with 2 becoming possible cat5s
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35. Skyepony (Mod)
Dr Masters~ Great blog & on a Saturday:) I was wundering..Do you think there is still no chance we will ever see another season like 2005 again in our lifetime?
Member Since: August 10, 2005 Posts: 172 Comments: 38121
34. IKE
Quoting pottery:

Or maybe just one continuous, mega-cane that goes on for 6 months....


This looks like the complete opposite of 2009. We may all be wishing it was that slow from what I've read.
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Quoting pottery:

Or maybe just one continuous, mega-cane that goes on for 6 months....


Lol that would be something!
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32. JRRP
Quoting pottery:


OK, seems the math is too difficult, so here you go--
2005 had 28 named systems
Add 50%, =14
Total = 42 named systems for 2010, based on a 50% increase in Trop. Waves to date over 2005.
(I think I will change my prediction on the Competition Blog LOLOL)

jajajajajaja
well my prediction
17 name storm
10 hurricanes
6 mayor
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Quoting IKE:


LOL...42? The entire Atlantic basin would be bombarded.

My prediction was 13-7-4. Probably too low.

Or maybe just one continuous, mega-cane that goes on for 6 months....
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Quoting Weather456:
Thanks for the acknowledgement Dr. Masters.

In other news...this is the type of high we might be seeing often this hurricane season



Would that mean that the Caribbean, Central America, Mexico and Gulf coast states are probably at higher risks this season due to southerly and westerly tracks?
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29. IKE
Quoting pottery:


OK, seems the math is too difficult, so here you go--
2005 had 28 named systems
Add 50%, =14
Total = 42 named systems for 2010, based on a 50% increase in Trop. Waves to date over 2005.
(I think I will change my prediction on the Competition Blog LOLOL)


LOL...42? The entire Atlantic basin would be bombarded.

My prediction was 13-7-4. Probably too low.
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Quoting ryang:


What would that mean for us here in the Lesser Antilles?


The Lesser Antilles is highest risk area of the 2010 Atlantic Hurricane Season. We lie in the warmest waters, lowest pressures, wettest conditions and just south of the subtropical ridge. It seriously does look good for us this year.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting pottery:


OK, seems the math is too difficult, so here you go--
2005 had 28 named systems
Add 50%, =14
Total = 42 named systems for 2010, based on a 50% increase in Trop. Waves to date over 2005.
(I think I will change my prediction on the Competition Blog LOLOL)
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Quoting Weather456:
Thanks for the acknowledgement Dr. Masters.

In other news...this is the type of high we might be seeing often this hurricane season




What would that mean for us here in the Lesser Antilles?
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Quoting IKE:
First try at inserting oil siphon tube failed, BP says...from CNN.

More bad news.


The ACME company will be delivering the latest road runner booby trap soon so Wile E Coyote super genius can fail again...what else is new?
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New York Times
Small Setback in Effort to Cap Oil in Gulf
By LIZ ROBBINS
Published: May 15, 2010

In their latest setback in stopping the flow of crude oil gushing into the Gulf of Mexico, BP officials said on Saturday that they had failed to insert a mile-long tube into the riser of the leaking well on Friday night. But they hoped to reattach the pipe by late Saturday night, said BP’s chief operating officer, Doug Suttles.

“When they attempted to connect to it, the frame shifted, so they were unable to make the connection,” Mr. Suttles said at a news conference in Robert, La. Workers had to pull the device back to the surface to make adjustments, he said. Officials hope that the pipe, when connected, will help siphon oil into a tanker on the surface of the Gulf.The problem in this failed attempt, he said, had little to do with cold temperatures or high pressure that had foiled last week’s effort to cap the flow of leaking oil with a containment dome.

“It was just a mechanical act of taking a 5,000-foot long stream of pipe and connecting it to the tool,” Mr. Suttles said.

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23. IKE
First try at inserting oil siphon tube failed, BP says...from CNN.

More bad news.
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22. IKE
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.
.....

It all starts in...

392 hours...
16 minutes...
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TWDAT says 'weak to moderate convection' in the wave approaching here.
That's cool with me........
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Thanks for the acknowledgement Dr. Masters.

In other news...this is the type of high we might be seeing often this hurricane season


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

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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.