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: 169 - 119

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



Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting CybrTeddy:
Imo, this wave might be the wave that the GFS predicts develops into a weak TS around Tuesday.. emerges from South America and develops in the W Caribbean.
I see what you're talking about, but it isn't TS strength. I also don't think it is the same wave.

GFS 18z 66 Hours - Notice the 1011 MB surface low just east of Belize.



Member Since: Posts: Comments:
167. Skyepony (Mod)
The 1st station is toward the NW side, the 2nd is in NE side of the Central Atlantic Wave. Impressive water temps.

Station 41040
NDBC
Location: 14.477N 53.008W
Conditions as of:
Sat, 15 May 2010 23:50:00 UTC
Winds: ENE (70°) at 15.5 kt gusting to 17.5 kt
Significant Wave Height: 8.2 ft
Dominant Wave Period: 9 sec
Atmospheric Pressure: 29.99 in and rising
Air Temperature: 81.7 F
Water Temperature: 82.9 F


Station 41041
NDBC
Location: 14.357N 46.008W
Conditions as of:
Sat, 15 May 2010 23:50:00 UTC
Winds: E (100°) at 17.5 kt gusting to 23.3 kt
Significant Wave Height: 9.5 ft
Dominant Wave Period: 9 sec
Atmospheric Pressure: 30.01 in and rising
Air Temperature: 81.0 F
Dew Point: 73.6 F
Water Temperature: 81.0 F
Member Since: August 10, 2005 Posts: 161 Comments: 37336
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Member Since: Posts: Comments:
Quoting CybrTeddy:
Imo, this wave might be the wave that the GFS predicts develops into a weak TS around Tuesday.. emerges from South America and develops in the W Caribbean.


The GFS is predicting a TS on tuesday??
Member Since: Posts: Comments:
Imo, this wave might be the wave that the GFS predicts develops into a weak TS around Tuesday.. emerges from South America and develops in the W Caribbean.
Member Since: Posts: Comments:




447
WFUS54 KLIX 160031
TORLIX
MSC047-160100-
/O.NEW.KLIX.TO.W.0013.100516T0031Z-100516T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
731 PM CDT SAT MAY 15 2010

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* TORNADO WARNING FOR...
HARRISON COUNTY IN SOUTHERN MISSISSIPPI...
THIS INCLUDES THE CITIES OF...LONG BEACH...NORTH OF GULFPORT...

* UNTIL 800 PM CDT

* AT 725 PM CDT...THE PUBLIC REPORTED A WATERSPOUT MOVING ON SHORE
NEAR THE WALMART IN LONG BEACH...MOVING NORTH AT 10 MPH. NWS RADAR
DETECTED SOME ROTATION WITH THIS STORM.

* THE TORNADO WILL BE NEAR...
LYMAN BY 800 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE SAFEST PLACE TO BE DURING A TORNADO IS UNDER A WORKBENCH OR OTHER
PIECE OF STURDY FURNITURE. SEEK SHELTER ON THE LOWEST FLOOR OF THE
BUILDING IN AN INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE
BLANKETS OR PILLOWS TO COVER YOUR BODY AND ALWAYS STAY AWAY FROM
WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Another very nice wave associated with the ITCZ about to emerge off of Africa.

Member Since: Posts: Comments:
Radar Image from CSTARS, May 14, 2010

ESL by LSU
Member Since: July 3, 2005 Posts: 420 Comments: 127543
159. Skyepony (Mod)
Steering 400-850mb..
Member Since: August 10, 2005 Posts: 161 Comments: 37336


2010 Hurricane Preparation
Member Since: July 3, 2005 Posts: 420 Comments: 127543
157. xcool
hurricane season Start" Early
Member Since: Posts: Comments:
Quoting Skyepony:
Can't help but look at the vigerious wave in the Central Atlantic. Windsat missed it today. ASCAT caught it earlier

May get it again in a bit.

There is definitely turning but not a closed low.
Member Since: Posts: Comments:
Quoting stormpetrol:

True Pat I know, but it sames like everything these days are defying the norm was just wondering that's all.


Nothing would surprise me this season.
Member Since: Posts: Comments:
154. xcool
Tornado strikes LaPlace area, damaging one building and causing minor injuries


By The Times-Picayune
May 15, 2010, 4:28PM
A small tornado touched down Saturday morning three miles southwest of LaPlace, damaging a building and causing minor injuries to one person.

According to the National Weather Service, the tornado began as a water spout over the Mississippi River, crossing a levee into Lucy at 7:11 a.m.

Measuring 100 yards long and 50 feet wide, with winds of 40 to 72 mph, the tornado damaged the roof of a mobile home. One person suffered cuts and scrapes.
Member Since: Posts: Comments:
153. Skyepony (Mod)
Can't help but look at the vigerious wave in the Central Atlantic. Windsat missed it today. ASCAT caught it earlier

May get it again in a bit.

Member Since: August 10, 2005 Posts: 161 Comments: 37336
Quoting xcool:
i give estimated to be less than 20%.


..MiamiHurricanes09 ...
Me too.
Member Since: Posts: Comments:
Convection definitely waning, I doubt it will develop unless it can get convection quick in the morning.

Member Since: Posts: Comments:
150. xcool
i give estimated to be less than 20%.


..MiamiHurricanes09 ...
Member Since: Posts: Comments:
Hi, all! Posted a new blog with updated flyer/info for the 2010 Portlight/WU Honor Walk & Roll. Please check it out!

LST's Blog

Floodman and I will be walking the beautiful Fort Worth Botanical Gardens. Anyone who'd like to sponsor us, please WU mail us, or feel free to post a comment on my blog. We're shooting for 3-4 circuits around the gardens, for 6-8 miles.

Thanks to all of you for your continued support of Portlight and our disaster relief efforts!
Member Since: Posts: Comments:
Quoting xcool:



Wow it is improving, I don't foresee development though.
Member Since: Posts: Comments:
My first official blog entry. Please check it out and comment on your opinions. 2010 Hurricane Season Blog #1: Outlook
Member Since: Posts: Comments:
Howdy, we have 3 hours till the entrance into the Atlantic Season Prognostication contest is closed. Please feel free to place your picks! It is about numbers, not landfall.

Some who have asked for me to do this have yet to join???????

Link for ya :)

Atlantic Season Contest - Open till 11 EST
Member Since: June 12, 2005 Posts: 6 Comments: 8185
145. xcool



Member Since: Posts: Comments:
144. xcool
MiamiHurricanes09 wow
Member Since: Posts: Comments:
Quoting Tropicsweatherpr:


What does the chart shows about where is el nino 3.4?


Member Since: Posts: Comments:
Quoting Stormchaser2007:
.


What does the chart shows about where is el nino 3.4?
Member Since: Posts: Comments:
18z

Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
With the development still firing south,..training effect is beginning to pile up the inches Uptown.



Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting Skyepony:
Gamma~ it was reassuring after 2005..sure would like to see Jeff say it again..

That's a pretty vigorous wave in the Central Atlantic.
That wave reminds me of Fred last year.
Member Since: Posts: Comments:
Quoting stormpetrol:

Thanks, hopefully everything we be just fine, if not we'll have to abide by Mother Nature as she/it/HE rules!
Yup.
Member Since: Posts: Comments:
136. Skyepony (Mod)
Gamma~ it was reassuring after 2005..sure would like to see Jeff say it again..

That's a pretty vigorous wave in the Central Atlantic.
Member Since: August 10, 2005 Posts: 161 Comments: 37336
Screenshot

Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Thanks to Drak and Levi.
*In response to stormpetrol.

"The ECMWF EPS shows ridging occurring over the eastern seaboard on May 24th which if matched up with a good MJO pulse could breed some tropical activity in the Caribbean."



"As I showed a couple days ago, the ensembles are also showing an expansion of sub-1010mb surface pressures into the western Caribbean, indicating an increase in heat and convergence."



"GFS Ensembles continuing to show increased precipitation over the western Caribbean by the end of the month.

GFS ensembles precipitation Day 12:"



"The GFS ensembles are also showing a favorable pattern of high heights over low heights at this time-frame, with the center of lowest heights over central America. This is also an indication of where heat will be building and is a favorable pattern for tropical mischief in either the Caribbean or eastern Pacific.

GFS ensembles 500mb height normalized anomaly Day 12:"



Once again, this was all done my Levi and Drak.

Thanks, hopefully everything we be just fine, if not we'll have to abide by Mother Nature as she/it/HE rules!
Member Since: April 29, 2007 Posts: 0 Comments: 7664
Quoting Weather456:


all were added using paint shop pro. The arrows did not come with the program, they were custom made. The "L" is basically writing "L" in word art form.
Oh thanks.
Member Since: Posts: Comments:
Belize is protected very nicely by the honduran coast as most hurricanes move nw so the only way we can receive a huricane is if they move due west which is not to often
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
How do you add the arrows and low pressure symbols on tinypic?


all were added using paint shop pro. The arrows did not come with the program, they were custom made. The "L" is basically writing "L" in word art form.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting Weather456:
Sea breeze front - Cuba

Because of how Cuba is shaped air flows off the Caribbean Sea and Atlantic Ocean. Both air flows coming from each side of the coast, collide inwards. First, you see a line of cumulus clouds and if conditions are right, you get thunderstorms.




Tropical Wave


How do you add the arrows and low pressure symbols on tinypic?
Member Since: Posts: Comments:
Quoting Patrap:

That can't be right, can it? I mean the GOM has -1 Cat. 4-5 storms what about 04-05, and 08. Or does this not include this decade?
Member Since: Posts: Comments:
Thanks to Drak and Levi.
*In response to stormpetrol.

"The ECMWF EPS shows ridging occurring over the eastern seaboard on May 24th which if matched up with a good MJO pulse could breed some tropical activity in the Caribbean."



"As I showed a couple days ago, the ensembles are also showing an expansion of sub-1010mb surface pressures into the western Caribbean, indicating an increase in heat and convergence."



"GFS Ensembles continuing to show increased precipitation over the western Caribbean by the end of the month.

GFS ensembles precipitation Day 12:"



"The GFS ensembles are also showing a favorable pattern of high heights over low heights at this time-frame, with the center of lowest heights over central America. This is also an indication of where heat will be building and is a favorable pattern for tropical mischief in either the Caribbean or eastern Pacific.

GFS ensembles 500mb height normalized anomaly Day 12:"



Once again, this was all done my Levi and Drak.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
I think you well be disrupted greatly by the upcoming upward motion MJO. Plus models are showing development in that region for those dates.
We live in the tropics and are used to a lot of rain a tropical storm will just be some excitment .
Member Since: Posts: Comments:
Sea breeze front - Cuba

Because of how Cuba is shaped air flows off the Caribbean Sea and Atlantic Ocean. Both air flows coming from each side of the coast, collide inwards. First, you see a line of cumulus clouds and if conditions are right, you get thunderstorms.




Tropical Wave


Member Since: July 24, 2005 Posts: 407 Comments: 19076
124. xcool



Member Since: Posts: Comments:
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting MiamiHurricanes09:
I think you well be disrupted greatly by the upcoming upward motion MJO. Plus models are showing development in that region for those dates.

Wow! I don't need to hear that can you post the model for me please or give me the link, thanks.
Member Since: April 29, 2007 Posts: 0 Comments: 7664
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting GTcooliebai:

I can't even see Florida
And I live there, lol, not good.
Member Since: Posts: Comments:

Viewing: 169 - 119

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.

Local Weather

Partly Cloudy
73 °F
Partly Cloudy