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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669. tornadodude
2:57 PM GMT on May 16, 2010
Quoting atmoaggie:

Sry, I'd be in your position if I ever tried...new territory.

back, L8R


oh ok, thanks tho
Member Since: June 28, 2006 Posts: 25 Comments: 8360
668. MiamiHurricanes09
2:57 PM GMT on May 16, 2010
Quoting doabarrelroll:


it already exists.

http://www.sun-sentinel.com/broadband/theedge/sfl-edge-t-canemaker,0,4142989.flash
That's a pretty bad game.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
667. atmoaggie
2:54 PM GMT on May 16, 2010
Quoting tornadodude:
hey Atmo, any help for me with tethering my blackberry? link

Sry, I'd be in your position if I ever tried...new territory.

back, L8R
Member Since: August 16, 2007 Posts: 6 Comments: 12463
665. hydrus
2:53 PM GMT on May 16, 2010
Quoting MiamiHurricanes09:
All you need is a hypercane, a wishcaster, and Florida. LMAO.

It almost looks like Mr Bill from Saturday Night Live. OH no, not Mr cyclone, he,ll be mean to me. ooohhh nooooo!....
Member Since: September 27, 2007 Posts: 1 Comments: 22314
664. MiamiHurricanes09
2:51 PM GMT on May 16, 2010
Time to go until June 1st.

15 Days
372 Hours
Member Since: September 2, 2009 Posts: 130 Comments: 21194
663. MiamiHurricanes09
2:48 PM GMT on May 16, 2010
Quoting TampaSpin:


Not at all.....i just posted with Graphics why i thought so as the Shear is droppping there is Voricity at 850mb and there is nice Convergence and Divergence already there.

Not moody just making my point!
I posted a graph yesterday, let me see if I can find it, showing where I think it'll develop and go.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
662. MiamiHurricanes09
2:47 PM GMT on May 16, 2010
Quoting TampaSpin:


Not at all.....i just posted with Graphics why i thought so as the Shear is droppping there is Voricity at 850mb and there is nice Convergence and Divergence already there.

Not moody just making my point!
Ok ok, lol, no hard feelings.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
661. MiamiHurricanes09
2:47 PM GMT on May 16, 2010
Quoting Patrap:
Someone should market a Board Game.

"Lets Build a Tropical Cyclone".. in 4 ez steps..by Milton Bradley.

All you need is a hypercane, a wishcaster, and Florida. LMAO.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
660. Patrap
2:46 PM GMT on May 16, 2010
Member Since: July 3, 2005 Posts: 427 Comments: 129444
659. Patrap
2:45 PM GMT on May 16, 2010
Member Since: July 3, 2005 Posts: 427 Comments: 129444
658. Patrap
2:43 PM GMT on May 16, 2010
ESL by LSU

Cosmo Skymed3 Image from CSTARS, May 14, 2010
Member Since: July 3, 2005 Posts: 427 Comments: 129444
657. TampaSpin
2:43 PM GMT on May 16, 2010
Quoting MiamiHurricanes09:
Tampaspin is a moody man huh?


Not at all.....i just posted with Graphics why i thought so as the Shear is droppping there is Voricity at 850mb and there is nice Convergence and Divergence already there.

Not moody just making my point!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
656. tornadodude
2:42 PM GMT on May 16, 2010
hey Atmo, any help for me with tethering my blackberry? link
Member Since: June 28, 2006 Posts: 25 Comments: 8360
655. TampaSpin
2:41 PM GMT on May 16, 2010
Quoting MiamiHurricanes09:
I said it yesterday, ECMWF is showing ridging along the eastern seaboard on the 24th or so, if you match that with an upward motion MJO, you are bound to breeding tropical activity.


It will be the GOM just off the Yucatan.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
654. Patrap
2:40 PM GMT on May 16, 2010
Someone should market a Board Game.

"Lets Build a Tropical Cyclone".. in 4 ez steps..by Milton Bradley.

Member Since: July 3, 2005 Posts: 427 Comments: 129444
653. MiamiHurricanes09
2:39 PM GMT on May 16, 2010
Tampaspin is a moody man huh?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
652. TampaSpin
2:38 PM GMT on May 16, 2010
One other thing...before i zipp out.....this Oil spill is truly much worse than BP has been leading everyone to believe for sure. Is't that just great to hide the evidence underwater by putting chemicals on the oil to make it less bouant. NICE! This is really getting out of hand and with a storm looming soon....this will be a Disater coming beyond what we could have thought at this point. JUST MY OPINION!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
651. bappit
2:37 PM GMT on May 16, 2010
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.
Member Since: May 18, 2006 Posts: 10 Comments: 6147
Member Since: September 2, 2009 Posts: 130 Comments: 21194


Threatened by spill, La. looks for its oil revenue share sooner

For Gulf Coast states now threatened by a major oil spill, more than a billion dollars are at stake.
Member Since: July 3, 2005 Posts: 427 Comments: 129444
www.deepwaterhorizonresponse.com
Member Since: July 3, 2005 Posts: 427 Comments: 129444
Quoting TampaSpin:


I doubt it.
I said it yesterday, ECMWF is showing ridging along the eastern seaboard on the 24th or so, if you match that with an upward motion MJO, you are bound to breeding tropical activity.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
That was a close one. Back to traffic school? lol..thanx everyone.
Member Since: September 27, 2007 Posts: 1 Comments: 22314
Gonna try to be productive today......everyone have a good one and NO FIGHTING KIDS!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Member Since: July 3, 2005 Posts: 427 Comments: 129444
Quoting BahaHurican:
I can understand the outrage at potential coverup of subsurface oil, but I think pple are forgetting that in many ways this oil leak is unprecedented. I wouldn't jump to accuse the government of a coverup just yet (though I wouldn't put it past BP) mainly because even the most experienced gov't officials have never had to deal with this situation before. Some of these developments are likely to be as surprising to them as they are to us. Even the oil "experts" are likely finding some unexpected difficulties here.

To me this means that journalists and the wider public need to be ever more vigilant about monitoring what happens with the leak. If ever there IS a potential for cover-up, it's definitely here, where "new" things are happening and pple don't automatically know what to expect.....


To each their own.. the less oil reported leaking, the less liable BP is... as they have refused to show us the video feed of the leaks, and have tried to take advantage of the fishermen help, I see no reason to trust them, or their numbers. They are in this for profit, and that is the bottom line. They immediately made the rounds in Washington when this happened to remind our elected officials HOW they got elected..

Everyone is entitled to an opinion, and to trust whom they choose. I find no reason to trust BP, they do not care about you, me or the Gulf of Mexico excepting how it affects their profit line. Tell me.. where is the 7 hours of missing data? The data that would be incriminating? They are an oil company.. how much has Exxon paid out from the Valdez spill? They have litigated it down to near nothing and delayed payment..
Member Since: September 23, 2006 Posts: 1 Comments: 2614
Quoting HaboobsRsweet:


It was, he had the video on here the other day.


Yeah I talked to him yesterday and he sold it to CBS and CNN, I think
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting MiamiHurricanes09:
I see development taking place in the NW Caribbean on May 22-May 24.


I doubt it.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting Patrap:
Was just going to move da cars and truck to Higher ground..when a lull has appeared here.

Been Bumpy am ..the last 2 hours here.

A little bump here, too. Now in stratiform territory. (Good thing, I think the dog needs to go :P )
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting HaboobsRsweet:


It was, he had the video on here the other day.


I dont know..but OZ has a really well,..inspired way of finding trouble on da road.

Member Since: July 3, 2005 Posts: 427 Comments: 129444
Quoting HaboobsRsweet:
Just because you have lower shear and warm SSTs, that does not automatically mean a system will gen up next week. The synoptic pattern is still pushing too far south. Need the fronts to lift a little farther to the north and the STJ is not in good position for Tropical activity. I expect over the next two to three weeks we see more and more trop waves that can not survive opening up a highly active mid June. I think once we get through the first storm we will see a few back to back.
I see development taking place in the NW Caribbean on May 22-May 24.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting hydrus:
Good Morning Pat. I saw a storm chaser almost have a car wreck on the news last night. They said his name was Brian Ozberg. Could that have been CycloneOz?


It was, he had the video on here the other day.
Member Since: May 20, 2009 Posts: 0 Comments: 1640
Quoting TampaSpin:
We need to start watching the GOM......Freaking Shear is starting to Drop and conditions are becoming more favorable for something to pop up there.

The LAST THING WE NEED TO HAPPEN! Geesh











I expect something to develop in this area possibly middle of this week.



I doubt it.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Was just going to move da cars and truck to Higher ground..when a lull has appeared here.

Been Bumpy am ..the last 2 hours here.
Member Since: July 3, 2005 Posts: 427 Comments: 129444
Just because you have lower shear and warm SSTs, that does not automatically mean a system will gen up next week. The synoptic pattern is still pushing too far south. Need the fronts to lift a little farther to the north and the STJ is not in good position for Tropical activity. I expect over the next two to three weeks we see more and more trop waves that can not survive opening up a highly active mid June. I think once we get through the first storm we will see a few back to back.
Member Since: May 20, 2009 Posts: 0 Comments: 1640
Quoting Patrap:
Good Morning Pat. I saw a storm chaser almost have a car wreck on the news last night. They said his name was Brian Ozberg. Could that have been CycloneOz?
Member Since: September 27, 2007 Posts: 1 Comments: 22314
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.

Correct Patrap.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting eddye:
why is it not developing miami hurricane
African waves don't develop this time of year because of:

High shear
High SAL
Cold SSTs
Embedded in the ITCZ
Member Since: September 2, 2009 Posts: 130 Comments: 21194
We need to start watching the GOM......Freaking Shear is starting to Drop and conditions are becoming more favorable for something to pop up there.

The LAST THING WE NEED TO HAPPEN! Geesh











I expect something to develop in this area possibly middle of this week.



Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting Patrap:

I see the threat has basically passed for NOLA-proper...
Member Since: August 16, 2007 Posts: 6 Comments: 12463
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.

Member Since: July 3, 2005 Posts: 427 Comments: 129444
Member Since: July 3, 2005 Posts: 427 Comments: 129444
5/16/10


5/16/08
Member Since: September 2, 2009 Posts: 130 Comments: 21194
...And besides, nothing is going to form in 55 knot shear.
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624. eddye
why is it not developing miami hurricane
Member Since: Posts: Comments:
Quoting beell:


That's a good question, t'dude. The area SW of Abilene has been active for 2-3 days. Usually a combination of the stalled boundary intersecting with an outflow boundary. The old cold front boundary is getting pretty weak/difuse but it's possible. But there may be a little bit of a ridge building into the area that may put a damper on deeper convection.

I see you have the Day 1 posted. Both areas mentioned. If you're on a budget, it might pay to wait and see if the Big Bend activity leaves a boundary or two for later this afternoon. Like you said earlier. The whole thing is marginal.

Good Luck and be safe!

WHILE FLOW IN MOST AREAS WILL REMAIN FAIRLY WEAK...A 30-40 KT WLY
MID LVL JET WILL PERSIST TODAY OVER OK AND N TX ON SRN SIDE OF
SLOWLY-PROGRESSIVE CNTRL PLNS UPR LOW. THIS FEATURE WILL BE
ACCOMPANIED BY SEASONABLY COOL MID LVL TEMPS /AROUND MINUS 15 C AT
500 MB/. COUPLED WITH PWS OF 1.00-1.25 INCHES AND MODERATE TO
STRONG SFC HEATING...SETUP SHOULD FOSTER THE DEVELOPMENT NUMEROUS
DIURNALLY-ENHANCED STORMS ALONG AND S OF AFOREMENTIONED FRONT


FARTHER S...OTHER
STORMS...INCLUDING SUPERCELLS...MAY REDEVELOP/EVOLVE FROM ONGOING
CLUSTER NOW NEAR THE TX BIG BEND. AVAILABILITY OF RICH MOISTURE IN
THIS REGION MAY COMPENSATE FOR MORE LIMITED DEEP SHEAR TO YIELD A
THREAT FOR LARGE HAIL AND POSSIBLY A TORNADO


I'll probably just hang in this area for the day then, thanks!

anyone know how to guide me through this? I cant figure it out. link
Member Since: June 28, 2006 Posts: 25 Comments: 8360
BWgurl, u should prolly contact admin abt that... likely to be a computer issue more so than a contract issue...
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Quoting eddye:
where is the wave that just left africa does it look like it will become anything
Nope, looks pretty dead to me...

Member Since: September 2, 2009 Posts: 130 Comments: 21194
I've been curious. Why does the E Pacific season start before the ATL season?
Thanks.
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619. eddye
i mean africa lol
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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.