Record Atlantic SSTs continue in the hurricane Main Development Region

By: Dr. Jeff Masters , 8:03 PM GMT on May 15, 2010

Share this Blog
7
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 569 - 519

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27Blog Index

Good Morning Everyone,
Pottery you having the calm before the storm this morning?

Taco :o)
Member Since: July 7, 2005 Posts: 6 Comments: 3261
Notice the SW Caribbean...

00z GFS 180 Hours
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting JRRP:
00z GFS 180 hr
Good Morning all!

Yes that 1006 MB low in the southwest Caribbean is the wave to the east of Trinidad and Tobago. The 00z CMC shows the same solution. I think that it will develop to possibly a TD once it gets to the SW Caribbean but a band of high shear lies to the north of it, so not too much development there.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
566. JRRP
00z GFS 180 hr
Member Since: August 16, 2007 Posts: 0 Comments: 6165
Good Morning all.
Conditions in Trinidad are sunny, hot (already) and pretty still. Scattered cloud and haze.
The wave east of here is still trying to force its way through a "wind wall" of strong north-easterly flow that is blowing the thing away.
Still hope to get some showers but I may have to wash my car to guarantee that....
Member Since: October 24, 2005 Posts: 0 Comments: 24653
564. IKE
And Gulf Shores,AL....

Member Since: Posts: Comments:
Yup -- constant roll of thunder preceeding it.
Member Since: Posts: Comments:
562. IKE
One west of Milton dropping some heavy rains.
Member Since: Posts: Comments:
How bout it Ike --- Pretty intense T-storm heading our way. Pretty much at my door step now
Member Since: Posts: Comments:
Good Morning

Blog Update

Weak tropical disturbance is expected to develop later this weekend; Eyjafjallajökull continues to erupt
Member Since: July 24, 2005 Posts: 407 Comments: 19076
559. IKE
Quoting stormhank:
Morning IKE,,,how have you been?? I posted you a comment on your blog...Whats your thoughts on up coming hurricane season? Ive read and herd its going to be a bad one?


I'm not an expert...I'll take what they're saying about it and agree.

The oil spill is going to cause even more problems I feel.

They need to get it stopped. Maybe what they're doing now will work.
Member Since: Posts: Comments:
Morning IKE,,,how have you been?? I posted you a comment on your blog...Whats your thoughts on up coming hurricane season? Ive read and herd its going to be a bad one?
Member Since: September 8, 2005 Posts: 0 Comments: 1386
Quoting IKE:


I agree that BP has been BS'ing long enough. The oil is gushing out much faster than BP is telling.


Good morning Ike! The thing that has me surprised is what "I" see as government complicity in the artificially low numbers. The entity with the most to lose, is the one providing the numbers that our government is offering for public digestion. Again, I feel the President has to the power to make a LOT of corrections in past policies and move forward with tighter regulations, and a VIABLE alternative energy policy. He has the political coin to make a lot of things better and safer, I hope he uses it wisely.
Member Since: Posts: Comments:
good morning all

I made it to Abilene, Texas yesterday. Hoping to chase a little today, not a great chance of storms, but should be fun.


any thought on the severe potential around wednesday?
Member Since: Posts: Comments:
555. IKE
Quoting indianrivguy:
Aussie.. well enough thank you.. warm, soft SE breeze.. I have a yard sale going so I hope rain stays away until later...

I see the cover up happening in the BP oil spill is continuing, then they can claim it is "less" than it really is, and no one can prove it. I seriously hope the President stops being a politician, becomes our leader and leans on these folks with all the power his office can muster.

..and the upcoming hurricane season has me VERY nervous..


I agree that BP has been BS'ing long enough. The oil is gushing out much faster than BP is telling.
Member Since: Posts: Comments:
554. IKE
Member Since: Posts: Comments:
553. ryang
Quoting stormhank:
Anyone know when NOAA will be releasing their 2010 hurricane predictions? Normally its mid may?


On the 20th of May (thursday)
Member Since: Posts: Comments:
Good Morning everyone
Member Since: Posts: Comments:
Anyone know when NOAA will be releasing their 2010 hurricane predictions? Normally its mid may?
Member Since: September 8, 2005 Posts: 0 Comments: 1386
Quoting Tropicsweatherpr:


Good evening and good morning to the rest.The news so far is that some homes and roads have small cracks in western PR.Many people went out from the condos and theaters as the projector and seats there were shaking.So far no reports of casualties.Link below is in spanish.

Link

Interesting, thanks for the link. I have Chrome, it translated it for me.
Member Since: September 30, 2007 Posts: 9 Comments: 15962
Aussie.. well enough thank you.. warm, soft SE breeze.. I have a yard sale going so I hope rain stays away until later...

I see the cover up happening in the BP oil spill is continuing, then they can claim it is "less" than it really is, and no one can prove it. I seriously hope the President stops being a politician, becomes our leader and leans on these folks with all the power his office can muster.

..and the upcoming hurricane season has me VERY nervous..
Member Since: Posts: Comments:
Mornin all....heres my numbers for 2010 season..16 8 4..... seems it maybe a close rival to 2005 from what ive herd and read,,hopefully not that severe though, any thoughts??
Member Since: September 8, 2005 Posts: 0 Comments: 1386
545. IKE
Looks like a low spinning in southern LA headed east...

Member Since: Posts: Comments:
544. IKE
From Accuweather from May 13th...


2010 Atlantic hurricane season could rank in the top ten
May 13, 2010; 6:00 AM ET

The upcoming hurricane season could be a top 10 active year, a stark contrast from the relatively calm 2009 season.

AccuWeather.com Chief Hurricane Meteorologist Joe Bastardi predicts a total of 16-18 storms this season. To put that in perspective, only eight years in the 160 years of records have had 16 or more storms in a season.

The season should start early with one or two threats by early July, and stay late with additional threats extending well into October.

His forecast team expects at least six storms to impact the United States coastline--slightly more than one out of every three. In a normal year, one out of every five named storms (20 percent) in the Atlantic basin impacts the United States. In the 2005 season, 36 percent of the storms affected the United States, while 50 percent impacted the United States in 1998 and 2008.

"From the standpoint of number of storm threats from the tropics to the United States coastline, we will at least rival 2008, and in the extreme case, this season could end up in a category only exceeded by 2005," Bastardi said.

Bastardi observes a rapid warming of the Gulf of Mexico and the collapsing El Nino pattern, which were both characteristics of the 1998 and 2005 seasons.

Named storms moving through the Gulf of Mexico can cause major disruption to both oil and gas production. In 2008, shutdown of production caused a decline in production of 62 million barrels of oil and 408 billion cubic feet of gas. In the record-setting season of 2005, nearly three months of production time was lost.

According to Bastardi, the Atlantic basin looks "textbook" for a major season, with many long track storms that make their way from off the coast of Africa into the western Atlantic and Caribbean heading toward the United States coastline.

He adds that in the heart of the season, there will be a "congregation of tracks," or a concentrated area where many of the storm tracks will pass through.

"I believe there will be a bunching of tracks in the area around the Antilles and into the Bahamas," he said.
Member Since: Posts: Comments:
Quoting AussieStorm:
Evening all. Has there been any damage from the PR Quake?


Good evening and good morning to the rest.The news so far is that some homes and roads have small cracks in western PR.Many people went out from the condos and theaters as the projector and seats there were shaking.So far no reports of casualties.Link below is in spanish.

Link
Member Since: Posts: Comments:
542. IKE
Rain knocking on my door in the Florida panhandle....

Member Since: Posts: Comments:
Quoting indianrivguy:
Good morning everyone.. good evening Mr. Aussie!!

Evening, how's your part of the world?
It's meant to be showers all week here in Sydney.
Member Since: September 30, 2007 Posts: 9 Comments: 15962
Morning Indian!
Member Since: Posts: Comments:
Good morning everyone.. good evening Mr. Aussie!!
Member Since: Posts: Comments:
Quoting P451:


From about Hour 120 onward.... looks like it wants something to fester and then take off.

Entirely possible and it could end up being from the mess that is off the NE South American coastline.



I was talking about this last night, the GFS had it much more northward but no where near as strong. The GFS is having consistency, its being hanging on to a storm for a few weeks, if you remember Bertha you'll remember that the GFS held onto it for a few weeks also with no other model support until a few days before Bertha actually formed.
Member Since: Posts: Comments:
Good Morning to all from Barbados, conditions; presently under blue morning sky's with a hint of scattered clouds:

Dew Point: 25 °C
Wind: 22 km/h / 6.2 m/s from the East
Pressure: 1013 hPa (Steady)
Heat Index: 33 °C
Visibility: 10.0 kilometers
UV: 2 out of 16
Clouds:
Few 548 m
Scattered Clouds 3048 m
(Above Ground Level)
Member Since: Posts: Comments:
Evening all. Has there been any damage from the PR Quake?
Member Since: September 30, 2007 Posts: 9 Comments: 15962
534. IKE
6Z GFS....
Member Since: Posts: Comments:
Good morning Hank!
Member Since: Posts: Comments:
mornin anyone on yet?
Member Since: September 8, 2005 Posts: 0 Comments: 1386
530. xcool
LOL .YOU TOO
Member Since: Posts: Comments:
529. JLPR
Quoting xcool:
ECMWF Model BESTS ....





NGP


ah, but Nogaps hardly develops anything lol! XD
Well I guess we should keep an eye on Africa, those SSTs are hot!
Well goodnight to you and everyone! ^^
Member Since: Posts: Comments:
528. xcool
ECMWF Model BESTS ....





NGP
Member Since: Posts: Comments:
527. JLPR
Quoting xcool:
..true


But if it did happen now that would be simply nuts! XD
Member Since: Posts: Comments:
526. xcool
..true
Member Since: Posts: Comments:
525. JLPR
Quoting xcool:
BY

africa








WTH! But at least it is long range, it'll probably never happen :)
Member Since: Posts: Comments:
Strange that the CFS Summer precip. outlook shows both June and September below average in Florida.
Member Since: Posts: Comments:
523. xcool
BY

africa






Member Since: Posts: Comments:
Here is the graphic from the seismic office in Mayaguez.

Member Since: Posts: Comments:
521. JLPR
Quoting Hurakantaino:
JRRP, se sintio tambien in the NW, Aguadilla, pretty strong.


ha! NW, hadn't noticed that, it must have been quite the shake over there, you're closer to the epicenter
Member Since: Posts: Comments:
520. JLPR
Quoting Tropicsweatherpr:
Yo estoy bien pero el susto fue grande en la cama ya que se movio bastante.

I am fine but the bed shaked a good deal and I was awaken.I am in San Juan.


I'm in Carolina and felt it, anyone from the west side of the island?
Member Since: Posts: Comments:
Yo estoy bien pero el susto fue grande en la cama ya que se movio bastante.

I am fine but the bed shaked a good deal and I was awaken.I am in San Juan.
Member Since: Posts: Comments:

Viewing: 569 - 519

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.