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 Engine2:
My guess is they still have fear about the European market - specifically the fiscal crisis in Greece

Thanks
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1118. Engine2
Quoting severstorm:

What causing them to go nuts like that?
My guess is they still have fear about the European market - specifically the fiscal crisis in Greece
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Quoting TampaSpin:
Ouch the Asian Markets are getting hammered!

Asian Indexes
Index Country Change % Change Level

Australia ASX All Ordinaries Australia -142.30 -3.06%

Shanghai SE Composite Index China -136.70 -5.07%

Hang Seng Hong Kong -430.23 -2.14%

Mumbai Sensex India -159.04 -0.94%

Nikkei 225 Japan -226.75 -2.17%

Taiwan TSEC 50 Index Taiwan -173.41 -2.23%

What causing them to go nuts like that?
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1116. hydrus
Quoting TampaSpin:
Ouch the Asian Markets are getting hammered!

Asian Indexes
Index Country Change % Change Level

Australia ASX All Ordinaries Australia -142.30 -3.06%

Shanghai SE Composite Index China -136.70 -5.07%

Hang Seng Hong Kong -430.23 -2.14%

Mumbai Sensex India -159.04 -0.94%

Nikkei 225 Japan -226.75 -2.17%

Taiwan TSEC 50 Index Taiwan -173.41 -2.23%
I hope that is not an indication for the U.S. market.
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1115. hydrus
Quoting tornadodude:
Good morning all!

I am currently in Amarillo, Texas right now, just had a decent storm come through about an hour ago.

I look to be in a pretty good location for today and especially tomorrow. On wednesday, I will be going back into Oklahoma. I look for the SPC to issue a moderate risk outlook for wednesday.

Anyway, we hopefully caught some great footage of a tornadic supercell on the south side of Oklahoma City yesterday. We were guided by CycloneOz, Hurricane Junky, and a few others so thanks!!

I haven't yet had time to review our video from the storm yesterday, but I know we got a wall cloud and probably the funnel cloud on video.

Btw, it is stinkin flat out here!!
Good luck out there in tornado alley. Looking forward to the footage.
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Ouch the Asian Markets are getting hammered!

Asian Indexes
Index Country Change % Change Level

Australia ASX All Ordinaries Australia -142.30 -3.06%

Shanghai SE Composite Index China -136.70 -5.07%

Hang Seng Hong Kong -430.23 -2.14%

Mumbai Sensex India -159.04 -0.94%

Nikkei 225 Japan -226.75 -2.17%

Taiwan TSEC 50 Index Taiwan -173.41 -2.23%
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Quoting severstorm:

HYPE There all guessing. I don't think anyone knows what impact we will have at the moment. JMO.



HYPE..........LOL.....whatever. I don't think anyone has hyped anything but, BP and our Government not creating HYPE!
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Quoting TampaSpin:
Worry that Gulf oil spreading into major current


OH NO!

HYPE There all guessing. I don't think anyone knows what impact we will have at the moment. JMO.
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Oops double post
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Good morning all!

I am currently in Amarillo, Texas right now, just had a decent storm come through about an hour ago.

I look to be in a pretty good location for today and especially tomorrow. On wednesday, I will be going back into Oklahoma. I look for the SPC to issue a moderate risk outlook for wednesday.

Anyway, we hopefully caught some great footage of a tornadic supercell on the south side of Oklahoma City yesterday. We were guided by CycloneOz, Hurricane Junky, and a few others so thanks!!

I haven't yet had time to review our video from the storm yesterday, but I know we got a wall cloud and probably the funnel cloud on video.

Btw, it is stinkin flat out here!!
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Worry that Gulf oil spreading into major current


OH NO!
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1108. RTLSNK
Quoting pottery:

No Pockets?? How do they carry their cell-phones???


I should know better than to get you started first thing in the morning! I couldn't find the answer to your last question, but I know that they can be pretty sneaky. I better get out of here now before Admin wakes up, once the season starts, no more funny cartoons! :)
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1107. pottery
Quoting RTLSNK:


They don't have any pockets remember?
You could just BBQ the little jokers,
they taste just like chicken. :)

No Pockets?? How do they carry their cell-phones???
Member Since: October 24, 2005 Posts: 0 Comments: 24307
Morning all, Looking like some needed rain today in w c fl. Oz saw your clip on the wc, great piece of driving. jeff9641 looks like you had some interesting weather over near your house last evening.
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1105. RTLSNK
Quoting pottery:

heheheheheh, Yeah! Gotta keep the serpents out of there this time.
Hey. Maybe I can set up a little booth, renting goggles and snorkels and flippers and stuff to them. Make a buck on the side......


They don't have any pockets remember?
You could just BBQ the little jokers,
they taste just like chicken. :)
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1104. RTLSNK
Quoting CycloneOz:


LOL!

This is great! Ossgss is my hurricane survival suit designer...and now you are our official chase vehicle designer.

I like this design...but semi's are too slow. How about something with a little more agility and less torque? :D


How about this one?
Not only does it look agile, it looks like it can also fly! :)
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1103. pottery
Quoting RTLSNK:


Morning Pottery, glad to see you finally got some rain. I would hope you've covered your rain barrels this time. :)

heheheheheh, Yeah! Gotta keep the serpents out of there this time.
Hey. Maybe I can set up a little booth, renting goggles and snorkels and flippers and stuff to them. Make a buck on the side......
Member Since: October 24, 2005 Posts: 0 Comments: 24307
1102. RTLSNK
Quoting pottery:
Good Morning.
Nice shower here early, 1/2" in about 20 mins. Cloudy and looming overhead.
But looking at the wave, it looks a little sick right now.


Morning Pottery, glad to see you finally got some rain. I would hope you've covered your rain barrels this time. :)
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Quoting RTLSNK:


Saw that on TWC last night, found a new chase Vehicle for you and TornadoDude,
you may want to reconfigure the front end design however. :)


LOL!

This is great! Ossgss is my hurricane survival suit designer...and now you are our official chase vehicle designer.

I like this design...but semi's are too slow. How about something with a little more agility and less torque? :D
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1100. RTLSNK
Quoting CycloneOz:
Looks like my little "near miss" Friday evening is the most popular video on The Weather Channel this morning. :)


Saw that on TWC last night, found a new chase Vehicle for you and TornadoDude,
you may want to reconfigure the front end design however. :)
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Quoting MahFL:
The wave is as dead as a dead parrot......


Mr. Praline: I wish to complain about this parrot what I purchased not half an hour ago from this very boutique.

Owner: Oh yes, the, uh, the Norwegian Blue...What's,uh...What's wrong with it?

Mr. Praline: I'll tell you what's wrong with it, my lad. 'E's dead, that's what's wrong with it!

Owner: No, no, 'e's uh,...he's resting.
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1098. MahFL
The wave is as dead as a dead parrot......
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Looks like my little "near miss" Friday evening is the most popular video on The Weather Channel this morning. :)
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1096. pottery
Good Morning.
Nice shower here early, 1/2" in about 20 mins. Cloudy and looming overhead.
But looking at the wave, it looks a little sick right now.
Member Since: October 24, 2005 Posts: 0 Comments: 24307
The next official hurricane season outlook from the government's National Oceanic and Atmospheric Administration is due on May 20.
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Morning all. Looks like the current "hot spot" of the day is going to be the NIndian, with two potential systems brewing one on either side of the Indian subcontinent.

I may not be around much today, but I'll be monitoring developments from afar...

Have a great one!
Member Since: October 25, 2005 Posts: 19 Comments: 22073
1093. RTLSNK
Morning early birds, woke up when the little boomers came thru Macon, Ga awhile ago.
Looks like some other wake up calls are coming:
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Quoting Levi32:
Now this is not something you see every day.....a tropical cyclone developing in the Arabian Sea:



It'll make for one helluva wave in about a week or so, huh? :)
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Thank you very much for the coordinates and the link to that cool mapping website! I learn something new every day!
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1090. barbamz
Good morning. There is a song on "Eiyafjallajökull" (eja - fjatla - jökütl), that may help to pronounce it:
http://www.myspace.com/elizanewman.
Hope the efforts to stop the spill will continue. Have a nice week!
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Assuming the official rate of 5000barrels per day, the DeepwaterHorizon spill has reached half-way toward matching that of the ExxonValdiz on 17Apr10 at 2:30amCentralStandardTime.

Go to the GreatCircleMapper, then copy&paste in
31n98w-13n98w, 31n80w-13n80w, 29n88w, 29n89w, 28.5n88.5w, 29.5n88.5w, 29.35n88.85w, 28.65n88.85w, 29.35n88.15w, 28.65n88.15w

The crude oil slick covers an area nearly equivalent to a circular*degree, 3740square-miles or 9680square-kilometres.

If the present rates of spillage and of spreading continue until the morning of 11June10, the spill will have reached the ExxonValdiz level, and the oil slick will cover an area*equivalent to that shown by the coordinates
31n98w-13n98w, 31n80w-13n80w, 29n87.6w, 29n89w, 28.3n88.3w, 29.7n88.3w, 28.5n87.8w, 28.5n88.8w, 29.5n87.8w, 29.5n88.8w
on the GreatCircleMap.

Somehow neither circle seems to be "tiny when compared to the size of the Gulf of Mexico" as claimed by BritishPetroleum's ChiefExecutiveOfficer.

TropicalStorm Arlene made landfall nearby on 11June05.
http://en.wikipedia.org/wiki/Tropical_Storm_Arlene_(2005)
"Two days prior to landfall, 36 oil platforms and 16 rigs were evacuated."

* Marked on the GreatCircleMaps by the respective last 8 coordinates posted above.
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1088. HadesGodWyvern (Mod)
India Meteorological Department
Tropical Cyclone Outlook
11:30 AM IST May 17 2010
==================================

Convective clouds are seen over south bay of bengal, andaman sea, and parts of central bay of bengal

Convective clouds are also seen over south arabian sea

Chief Meteorological Forecast
==============================

The low pressure area over southeast and adjoining Bay of Bengal is likely to intensify further
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1087. xcool





Member Since: September 26, 2009 Posts: 2 Comments: 15670
1086. Walshy
NWS in Blacksburg VA

Hydrology...
locallized heavy rain has occurred over parts of the area this
evening. Flooding and evacuations were reported in Greenbrier
County. Major flooding along a small stream (meadow creek) in
extreme northern Summers... 5.25 inches of rain measured in an
hours.
Streams and creeks also reported out of there banks in Ashe
County NC with 3-4 inches of rain there.

05/16/2010 0615 PM
4 miles NW of Sandstone, Summers County.
Dense fog, reported by public.
Report of 5.25 inches of rain in an hour. Whole trees
washed down the creek. Several homes with water damage.
Driveways and local roads closed.


05/16/2010 0610 PM
4 miles NW of Sandstone, Summers County.
Flash flood, reported by law enforcement.
Mud and rock slides reported along County Road 7 between
Sandstone and Meadow Creek WV. Meadow Creek out of its
banks and flowing across the Road.
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1085. xcool
ngp need too hurry uppp
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Quoting MiamiHurricanes09:
192 Hours - May 24th



The ridge the ECMWF is showing over the northeast will keep things interesting as far as track for any prospective storm...


I don't think that'll happen since most other models show an Omega Block over the Plains and Rockies with deep troughs on either side. Concurrent with a Negative NAO.
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Quoting Chicklit:

Evening folks. Too tired to post anything.
Stay safe out there. Goodnight!


ditto. JUst wanted to post this but it's 2am now. 2 big storms trying to form in the northern indian! I guess this is fairly normal for this time of year though. Gnight!

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Quoting Levi32:
Besides, the long-range model bashing isn't relevant. What we should be looking at is the overall pattern, and the potential for mischief is there with the MJO coming into our area of the world near the end of the month. The models will be all over the place of course, but they give us hints as to what could happen, and we use them as a tool to asses possible scenarios. When you see something like that on a model you ask yourself if it makes sense. If it doesn't, you can probably dismiss it, but if it does, and it looks like it could happen, then investigate it.


Point taken.
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1081. xcool
two models .show developing
Member Since: September 26, 2009 Posts: 2 Comments: 15670
1080. Levi32
Member Since: November 24, 2005 Posts: 635 Comments: 26647
1079. xcool





at gfs and cmc
Member Since: September 26, 2009 Posts: 2 Comments: 15670
1078. Levi32
Now this is not something you see every day.....a tropical cyclone developing in the Arabian Sea:

Member Since: November 24, 2005 Posts: 635 Comments: 26647
1077. KEEPEROFTHEGATE (Mod)
GFS SHORT RANGE GFS LONG RANGE
Member Since: July 15, 2006 Posts: 171 Comments: 53782
1076. Levi32
Besides, the long-range model bashing isn't relevant. What we should be looking at is the overall pattern, and the potential for mischief is there with the MJO coming into our area of the world near the end of the month. The models will be all over the place of course, but they give us hints as to what could happen, and we use them as a tool to asses possible scenarios. When you see something like that on a model you ask yourself if it makes sense. If it doesn't, you can probably dismiss it, but if it does, and it looks like it could happen, then investigate it.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
1075. Levi32
Quoting KoritheMan:


Too far out to mean much, IMO.


It does mean something when the Euro shows something like that. The Euro is a very conservative model when it comes to Atlantic tropical development. It hasn't shown even a hit of anything the GFS has tried to dish up so far this year, including the eastern Pacific. With the Euro joining the GFS in concert forecasting possible trouble in 10 days, I pay attention. We will see if this continues in subsequent runs on the Euro. If the Euro locks on to something for several days in a row, it's wise to give it consideration. We shall see if such a thing transpires.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
Quoting Levi32:
Check out the 12z ECMWF from this morning day 10. Closed 1010 isobar in the western Caribbean:



Too far out to mean much, IMO.
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1073. Levi32
Check out the 12z ECMWF from this morning day 10. Closed 1010 isobar in the western Caribbean:

Member Since: November 24, 2005 Posts: 635 Comments: 26647
1072. xcool
brb .
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Yeah. The forecast isn't so unreasonable either, seeing as though there should be a "hole" in the jet stream, if you will, which will allow for a period of low to moderate vertical shear. By the time the low gets its act together though, it already near sub-26C SSTs, hence why I believe it will be subtropical, if it develops at all.

Also, most importantly, the system ultimately completely detaches from the cold front in which it originates.
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Quoting KoritheMan:


I'm surprised nobody has mentioned the persistent forecast of a subtropical cyclone off the eastern seaboard in the next few days. The GFS, NOGAPS, and CMC have all been consistent in developing this.

i was wondering the same.
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1069. Patrap
That is Kinda funny I thought as well..Lil blips deep in the sheared tropics catches a few untrained eyes, but that Whoppa of a 980 Low dosent ?

Sheesh
Member Since: July 3, 2005 Posts: 423 Comments: 128236

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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.