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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I think we have a hard time conceptualizing that much energy in the ATL. Nobody bats an eye at 25 storms in the WPac....
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Atlantic Season Contest

Gotta run, but where are Storm, Drak, 456, Sky, Orca and on and on?

Be well all, L8R >>

Hey, it is your contest, I am just the conduit :)

Time is short! >>>> Out :)
Member Since: June 12, 2005 Posts: 6 Comments: 8185
NOAA will release their numbers on:

Thursday, May 20, 11:00 am EDT
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Weather456:
A more reasonable upper estimate is 20 named storms
A more reasonable lower estimate is 15 named storms.

2010 could rank in the top 10, possibly the top 5.

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?
Member Since: October 24, 2005 Posts: 0 Comments: 24033
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.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
re 311.

This sounds more in line w/ what I am expecting. I wouldn't be surprised to get to 21, or possibly even 23 (though I don't expect that). But in that active period of the 20s to 40s, there was only one 21+ season; other busy seasons were around 17....
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Getting very close to the Loop Current.
Member Since: Posts: Comments:
Quoting Weather456:
A more reasonable upper estimate is 20 named storms
A more reasonable lower estimate is 15 named storms.

2010 could rank in the top 10, possibly the top 5.
I agree.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
A more reasonable upper estimate is 20 named storms
A more reasonable lower estimate is 15 named storms.

2010 could rank in the top 10, possibly the top 5.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting KEEPEROFTHEGATE:
no it will not beat 2005 in number of systems maybe number of landfalling storms but i don't think we will see 32 systems like 05
Me either, but what do we know, anything is possible. Nobody expected 2005 was going to be so big. Do you know what I mean?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
2005 ATLANTIC SEASON
1 Tropical Storm ARLENE 08-13 JUN 60 30 -
2 Tropical Storm BRET 28-30 JUN 35 1002 -
3 Hurricane CINDY 03-07 JUL 65 992 1
4 Hurricane DENNIS 05-13 JUL 130 930 4
5 Hurricane EMILY 11-21 JUL 135 929 4
6 Tropical Storm FRANKLIN 21-29 JUL 60 997 -
7 Tropical Storm GERT 23-25 JUL 40 1005 -
8 Tropical Storm HARVEY 02-08 AUG 55 994 -
9 Hurricane IRENE 04-18 AUG 85 975 2
10 Tropical Depression TEN 13-14 AUG 30 1008 -
11 Tropical Storm JOSE 22-23 AUG 45 1001 -
12 Hurricane KATRINA 23-31 AUG 150 902 5
13 Tropical Storm LEE 28 AUG-02 SEP 35 1007 -
14 Hurricane MARIA 01-10 SEP 100 960 3
15 Hurricane NATE 05-10 SEP 80 979 1
16 Hurricane OPHELIA 06-18 SEP 80 976 1
17 Hurricane PHILIPPE 17-24 SEP 70 985 1
18 Hurricane RITA 18-26 SEP 150 897 5
19 Tropical Depression NINETE 30 SEP-02 OCT 30 1006 -
20 Hurricane STAN 01-05 OCT 70 979 1
21 Tropical Storm TAMMY 05-06 OCT 45 30 -
22 Tropical Depression TWENTY 08-09 OCT 30 1009 -
23 Hurricane VINCE 09-11 OCT 65 987 1
24 Hurricane WILMA 15-25 OCT 150 882 5
25 Tropical Storm ALPHA 22-24 OCT 45 998 -
26 Hurricane BETA 27-31 OCT 100 960 3
27 Tropical Depression TWENTY 14-16 NOV 30 1004 -
28 Tropical Storm GAMMA 18-21 NOV 40 1004 -
29 Tropical Storm DELTA 23-28 NOV 60 980 -
30 Hurricane EPSILON 29 NOV-08 DEC 75 979 1
31 Tropical Storm ZETA 30 DEC-06 JAN 55 994 -
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Look at how much further north the two lows over Africa are.... someone [Haboobsrsweet?] was mentioning detracting factors for May formation, and I concur with most if not all of what they said. However, if Twaves are going to be popping off the coast near 10N, we may after all be seeing a different story.
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Quoting Stormchaser2007:
Looks like the Gulf is going to go though another warming phase. This time the loop current may reach 90F. This model has verified excellent so far this year.

Current:


72 hours:
That is insanity, it will be very nice to see what happens.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
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

Link to the Iceland ash cloud forecast, ask your sister to call the airport, like, as soon as possible, they might cancel her flight:

Link
Recent article about air space closures in UK:

Link
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting MiamiHurricanes09:
This season could shape up far worse than 2005, we'll have to wait and see.
no it will not beat 2005 in number of systems maybe number of landfalling storms but i don't think we will see 32 systems like 05
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Looks like the Gulf is going to go though another warming phase. This time the loop current may reach 90F. This model has verified excellent so far this year.

Amazing.

Current:


72 hours:
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting KoritheMan:


I don't think mere tropical waves are potent enough to significantly upwell SSTs, at least not in the Caribbean, the area we typically see our most intense hurricanes.

No, I dont really think so either. I was being obscure.
But what a strange and peculiar set-up we have right now.
I think I will go and read those ancient Mayan texts again....
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Quoting KoritheMan:


I don't think mere tropical waves are potent enough to significantly upwell SSTs, at least not in the Caribbean, the area we typically see our most intense hurricanes.


the average winds in a tropical wave are less than 25 knots.

the average speed of a tropical wave is 10-20 knots.

i would not look for a tropical wave to upwell ssts enough to cool them by even 1C.

You would also need a series of tropical storms and hurricanes to cool the Atlantic to near normal and offset the rising sun as we near the peak of the NH summer.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
300. xcool
The Caribbean and GOM hottt
Member Since: September 26, 2009 Posts: 2 Comments: 15620
****
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Also nice to see an updated date in the lower left hand corner...
Member Since: October 25, 2005 Posts: 19 Comments: 21487
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
Member Since: Posts: Comments:
Quoting pottery:

Or we could see an unrelenting series of strong tropical waves, cooling the SST, releasing energy, and not amounting to anything!
(best case!)


I don't think mere tropical waves are potent enough to significantly upwell SSTs, at least not in the Caribbean, the area we typically see our most intense hurricanes.
Member Since: March 7, 2007 Posts: 553 Comments: 19915
Quoting BahaHurican:
Lol.... should have known....

I hope u do eventually get the showers there as the Twave moves west. It does look vigourous enough to bring some rain eventually.

I am sure we will get rain. Had some showers to the north of me today.
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Quoting BahaHurican:
Normally I merely observe the forecast competitions... but this year I thought I'd try my hand. Which leads me 2 ask: Who else has a forecast, or forecast update, between now and 1st June? I keep thinking at least two groups update around this time...


I know of 2: NOAA and the UK Met Office
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting BahaHurican:
Normally I merely observe the forecast competitions... but this year I thought I'd try my hand. Which leads me 2 ask: Who else has a forecast, or forecast update, between now and 1st June? I keep thinking at least two groups update around this time...
What are you speaking about?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting pottery:

Or we could see an unrelenting series of strong tropical waves, cooling the SST, releasing energy, and not amounting to anything!
(best case!)
Lol, probably not going to happen.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
26C waters washing the shores of the Cape Verde Islands in May. Simply amazing.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting MiamiHurricanes09:
This season could shape up far worse than 2005, we'll have to wait and see.

Or we could see an unrelenting series of strong tropical waves, cooling the SST, releasing energy, and not amounting to anything!
(best case!)
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Normally I merely observe the forecast competitions... but this year I thought I'd try my hand. Which leads me 2 ask: Who else has a forecast, or forecast update, between now and 1st June? I keep thinking at least two groups update around this time...
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Quoting WaterWitch11:


this is the one i saw the 3 girls waving at. i mean, it may be the pain medicine i've been taking but it just tripped me out. did you see the article on the rainbows in san diego?

http://eldgos.mila.is/eyjafjallajokull-fra-thorolfsfelli/


There are people up on that ridge all the time watching the volcano. The ash output has not significantly changed the last few days. It waxes and wanes. The wind has been changing directions thus giving the impression of more ash at times.
At this time there are no positive indications of any of the other volcanoes erupting. Is it possible? Yes. Probable? Even the experts don't know. History says it can happen, but also says it doesn't necessarily happen.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Weather456:


incredible
And you have to keep in mind that they have cooled because trade winds have increased.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting KEEPEROFTHEGATE:
compare maps 2010/2005



I've gotta admit, that looks very ominous for the upcoming hurricane season. Those water temps reflect more what we would typically expect in mid to late June to July rather than mid-May.
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:
compare maps 2010/2005



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

My whistle is fine, thanks...
I have alternative means, of wetting that.
Lol.... should have known....

I hope u do eventually get the showers there as the Twave moves west. It does look vigourous enough to bring some rain eventually.
Member Since: October 25, 2005 Posts: 19 Comments: 21487
Quoting pottery:

Like I said before, these are unprecedented conditions.
We have no idea what it all means...........
This season could shape up far worse than 2005, we'll have to wait and see.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting KEEPEROFTHEGATE:
compare maps 2010/2005


Like I said before, these are unprecedented conditions.
We have no idea what it all means...........
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Quoting BahaHurican:
Pat, why is it that red warning boxes, circles, lines, and other geometrical shapes are always positioned over the Bahamas????

Oh, forgot - hurricane haven of the ATL basin... :o(

Looks like the Guianas are going to get some tropical rainfall, though. Hope enough of it lasts to wet Pottery's whistle....


My whistle is fine, thanks...
I have alternative means, of wetting that.
Member Since: October 24, 2005 Posts: 0 Comments: 24033
If ya need a distraction, try this site :)

BTW, this is our Sun! How many Earths fit in there?



http://www.nasa.gov/mission_pages/sdo/main/index.html
Member Since: June 12, 2005 Posts: 6 Comments: 8185
compare maps 2010/2005

Member Since: July 15, 2006 Posts: 169 Comments: 53296
Other hurricane risks in the oil spill... this is not looking good.

1) The production system that the oil is going to go into (an FPSO) cannot operate in a hurricane and must disconnect from the source. So, assuming that they can get the spill going into an FPSO (failed first attempt yesterday) what are they going to do if a hurricane approaches?

2) The relief drilling operations must be suspended during a hurricane. Drill ships were lost at sea or damaged during hurricanes like Ike, Katrina, and Rita (and even Gustav). Note that even if temporary fixes work the well still needs a proper cement job to abandon it.

This is not what is going to be needed in the Gulf while cleaning up this mess....
Member Since: Posts: Comments:
Member Since: July 15, 2006 Posts: 169 Comments: 53296
My 3 best guesses of what the upward motion MJO will do:

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Patrap:
Pat, why is it that red warning boxes, circles, lines, and other geometrical shapes are always positioned over the Bahamas????

Oh, forgot - hurricane haven of the ATL basin... :o(

Quoting MiamiHurricanes09:
Convection definitely waning, I doubt it will develop unless it can get convection quick in the morning.

Looks like the Guianas are going to get some tropical rainfall, though. Hope enough of it lasts to wet Pottery's whistle....

Member Since: October 25, 2005 Posts: 19 Comments: 21487
Quoting Bordonaro:

Yes, I heard of that, do you have a link to the article. I pray and hope this is NOT a precursor of a large eruption.


this is where i saw it

http://www.theweatherspace.com/news/05-13-2010-Rainbow-similar-to-before-China-and-Chile-quake-seen -over-Los-Angeles.html

time to ice my back!
Member Since: August 11, 2008 Posts: 3 Comments: 1570
Quoting WaterWitch11:


this is the one i saw the 3 girls waving at. i mean, it may be the pain medicine i've been taking but it just tripped me out. did you see the article on the rainbows in san diego?

http://eldgos.mila.is/eyjafjallajokull-fra-thorolfsfelli/

Yes, I heard of that, do you have a link to the article. I pray and hope this is NOT a precursor of a large eruption.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Ossqss:


I think your property value just went up :)

Yeah! Good! LOLOL
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Quoting KEEPEROFTHEGATE:
BIG PICTURE

here is full north hemisphere water vapour sat image as of 903 pm




Took me a while to get my bearings there.
But really fascinating to watch the wave approaching Surinam etc blow up like that.
Bottom right corner.
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Quoting Bordonaro:

Good evening Water. There are two links below. The HVO/POR link shows 2 separate views of the eruption. Mulakot cam shows several pics around the "E" volcano, but you have to refresh to updates pics.

Mulakot web-cam: Link

HVO/POR link:Link

Recent Mulakot shot:


this is the one i saw the 3 girls waving at. i mean, it may be the pain medicine i've been taking but it just tripped me out. did you see the article on the rainbows in san diego?

http://eldgos.mila.is/eyjafjallajokull-fra-thorolfsfelli/
Member Since: August 11, 2008 Posts: 3 Comments: 1570
Member Since: September 2, 2009 Posts: 130 Comments: 21091

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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.