Record warmth in Atlantic Main Development Region for hurricanes

By: Dr. Jeff Masters , 4:52 PM GMT on March 08, 2010

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Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes were at their highest February level on record last month, 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 region between 10°N and 20°N, between the coast of Africa and Central America, 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.)


Figure 1. The departure of sea surface temperature (SST) from average for March 7, 2010, as derived from the AMSR and AVHRR satellite data. Image credit: NOAA.

SSTs in the Main Development Region (10°N to 20°N and 20°W to 85°W) were an eye-opening 1.02°C above average during February. This easily beats the previous record of 0.83°C set in 1998. SSTs in the Main Development Region are already warmer than they were during June of last year, which is pretty remarkable, considering February is usually the coldest month of the year for SSTs in the North Atlantic. The 1.02°C anomaly is the 6th highest monthly SST anomaly for the MDR on record. The only other months with higher anomalies all occurred during 2005 (April, May, June, July, and September 2005 had anomalies of 1.06°C - 1.23°C).

What is responsible for the high SSTs?
Don't blame El Niño for the high Atlantic SSTs. El Niño is a warming of the Pacific waters near the Equator, and has no direct impact on Atlantic SSTs. Instead, blame the Arctic Oscillation (AO) or its close cousin, the North Atlantic Oscillation (NAO). 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. They are some of the oldest known climate oscillations; seafaring Scandinavians described the pattern several centuries ago. Through east-west oscillation motions of the Icelandic Low and the Azores-Bermuda High, the AO/NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. The winter of 2009 - 2010 has seen the most negative AO and NAO patterns since record keeping began in 1950, which caused a very cold winter in Florida and surrounding states. A negative AO/NAO implies a very weak Azores-Bermuda High, which reduces the trade winds circulating around the High. During December - February, trade winds between Africa and the Lesser Antilles Islands in the hurricane Main Development Region were 1 - 2 m/s (2.2 - 4.5 mph) below average (Figure 2). 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 has heated up significantly, relative to normal, over the winter. This heating is superimposed on the very warm global SSTs we've been seeing over the past decade, leading to the current record warmth. Global and Northern Hemisphere SSTs were the 2nd warmest on record in both December and January.


Figure 2. Sea level pressure averaged for the period December 2009 - February 2010 (left) and the sea level pressure averaged for the period December - February from the long-term mean (1968 - 1998). This winter, the Azores-Bermuda High was about 3 - 4 mb weaker than in a typical winter, due to strongly negative AO/NAO conditions. Image credit: NOAA/ESRL.


Figure 3. Departure of surface wind speed from average for December 2009 - February 2010. Winds were about 1 - 2 m/s (2.2 - 4.5 mph) lower than average over the Atlantic hurricane Main Development Region (MDR). Image credit: NOAA/ESRL.

What does this imply for the coming hurricane season?
According to Dr. Phil Klotzbach of the University of Colorado, February temperatures in the MDR are not strongly correlated with active hurricane seasons. The mathematical correlation between hurricane season Accumulated Cyclone Energy (ACE) and February SSTs is only 0.26, which is considered weak. Past hurricane seasons that had high February SST anomalies include 1998 (0.83°C anomaly), 2007 (0.71°C anomaly), and 1958 (0.68°C anomaly). These three years averaged 13 named storms, 8 hurricanes, and 3 intense hurricanes, which is considerably higher than the average of 10, 6, and 2. The big question is, how long will the strong negative AO/NAO conditions keep the Azores-Bermuda High weak? Well, the AO has risen to near-neutral values over the past week, and the latest 2-week forecast from the GFS model show that the AO and NAO will not be as strongly negative during March. This should allow the Azores-Bermuda High to strengthen some this month and increase the trade winds over the MDR. However, I still expect we'll set a record for warmest-ever March SSTs in the Main Development Region. Longer term, the crystal ball is very fuzzy, as our ability to predict the weather months in advance is poor. The long-range NOAA CFS model is predicting SSTs in the Atlantic MDR will be about 0.70°C above average during the peak months of hurricane season, making it one of the top five warmest years on record--but not as warm as the unbelievable Hurricane Season of 2005, which averaged 0.95°C above normal during August - October. The other big question is, when will El Niño fade? El Niño is currently holding steady at moderate intensity, and I expect that will continue through at least mid-April. It is possible El Niño will linger long enough into the year that it will create increased wind shear that will suppress this year's hurricane season.

Brazilian disturbance
An area of disturbed weather off the coast of Brazil, near 24S 36W, has changed little over the past two days. This disturbance still has a slight potential to develop into subtropical or tropical depression by Wednesday, according to the latest runs of the ECMWF, GFS, and NOGAPS models. Satellite imagery shows little organization to the cloud pattern, and only limited heavy thunderstorm activity. Wind shear over the region is about 20 knots, which is rather high, and should keep any development slow. Sea surface temperatures are about 27°C, about 1°C above average, which is warm enough to support a tropical storm. The system is small, limiting its potential to become a tropical cyclone. I don't think it will become a subtropical depression.

I'll have a new post on Wednesday.
Jeff Masters

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LOL Atmo,

great minds think alike!
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Hi, my name is Matt, and I have an addiction to severe weather.

LOL

sounds an AA class or something
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199. MTWX
will wait and see what happens over the course of tomorrow to plan my attack so to speak.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Quoting MTWX:
My name is Nick. I'm a storm spotter in my free time... I have a rediculous love for severe weather, some may say an obsession...

(in somber AA-type tone)

Hi, Nick, welcome to the meeting.

On that, I shall bid you all adieu.
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197. MTWX
Quoting atmoaggie:

Seems like the timing, at least that given by NAM is such that you might miss out on the daytime surface warmth that far east...could be all wrong, here, just my impression.

Looking like a western MS event, to me. Natchez to Cleveland (MS)

I have a clear schedule... Just needs to be within driving distance.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Quoting MTWX:
Mid 60's at least... Columbus AFB, MS

Seems like the timing, at least that given by NAM is such that you might miss out on the daytime surface warmth that far east...could be all wrong, here, just my impression.

Looking like a western MS event, to me. Natchez to Cleveland (MS)
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195. MTWX
My name is Nick. I'm a storm spotter in my free time... I have a rediculous love for severe weather, some may say an obsession...
Member Since: July 20, 2009 Posts: 23 Comments: 1393
194. MTWX
Mid 60's at least... Columbus AFB, MS
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Quoting MTWX:
atmoaggie: thanks for the dew point forecast!! Looks like we may even reach dew points near 70!!

Who is we? (Where ya at?)
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192. MTWX
atmoaggie: thanks for the dew point forecast!! Looks like we may even reach dew points near 70!!
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Earthquakes in 2009

Special Earthquake Events
IRIS features special earthquake event pages to provide useful resources for the science community and the general public. These "Special Event" pages highlight earthquakes that had a major effect on a population or have some other unique scientific significance.

Magnitude 6.6 - QUEEN CHARLOTTE ISLANDS REGION



2009 November 17 15:30:46 UTC

The following is a release by the United States Geological Survey, National Earthquake Information Center:

A magnitude 6.6 earthquake struck in the Queen Charlotte Islands region off the coast of British Columbia, Canada, on Tuesday at 7:30 a.m. local time (1530 GMT). The quake was centered 250 km (155 miles) southwest of Prince Rupert, BC.

A PDF has been prepared with additional details about the earthquake. Download here

Read more | Maps

Magnitude 7.2 - FIJI



2009 November 09 10:44:54 UTC

The following is a release by the United States Geological Survey, National Earthquake Information Center:

The Fiji earthquake of 9 November 2009 occurred at the northern end of the inclined seismic zone that dips to the west beneath Tonga and Fiji. The broad-scale tectonics of the earthquake region are dominated by the relative convergence of the Pacific and Australia plates. The inclined seismic zone lies within the Pacific plate, which subducts westward beneath the Australia plate at the Tonga trench. At the latitude of the earthquake, the Pacific plate moves westward with respect to the interior of the Australia plate at a velocity of about 86 mm/y.

A two page PDF and a quicktime animation have been prepared with additional details about the earthquake. Download here

Read more | Maps

Magnitude 7.6 - VANUATU



2009 October 07 22:03:15 UTC

The following is a release by the United States Geological Survey, National Earthquake Information Center:

The Torres Islands, Vanuatu earthquake of October 7, 2009, occurred on or near the plate boundary between the Australia and Pacific plates. In the region of the earthquake, the Australia plate moves to the east-northeast with respect to the Pacific plate at a velocity of about 91 mm/year. The Australia plate thrusts under the Pacific plate at the New Hebrides trench and dips to the east-northeast. The October 7 earthquake’s location, depth, and focal mechanism are consistent with the earthquake having occurred as thrust-faulting associated with subduction along the Australia-Pacific plate boundary.

The Vanuatu region experiences a very high level of earthquake activity, with over a dozen events of magnitude 7 and larger having been recorded since the early decades of the twentieth century. The subducting Australia plate is seismically active to depths of about 350 km beneath the islands.

Recent large earthquakes near the October 7 event include a M 7.2 earthquake in 2007 and a M 7.3 earthquake in 1999.

Read more | Maps | Classroom presentation slides



Magnitude 7.6 - SOUTHERN SUMATRA, INDONESIA



2009 September 30 10:16:09 UTC

The following is a release by the United States Geological Survey, National Earthquake Information Center:

At least 1100 people were killed, 2181 were injured and thousands are still unaccounted for in the Padang area. More than 2650 buildings have been damaged in the area and landslides have disrupted power and communications. Felt (VII) at Padang. Widely felt throughout Sumatra and Java, Indonesia, Malaysia, Singapore and Thailand. A small local tsunami with wave heights of 27 centimeters (amplitude measured relative to normal sea level) was generated.

The magnitude 7.6 southern Sumatra earthquake of September 30, 2009 occurred as a result of oblique-thrust faulting near the subduction interface plate boundary between the Australian and Sunda plates. At the location of this earthquake, the Australian Plate moves northeast with respect to the Sunda plate at a velocity of approximately 65 mm/yr.

Read more | Maps



Magnitude 8.0 - SAMOA ISLANDS REGION



2009 September 29 17:48:11 UTC

The following is a release by the United States Geological Survey, National Earthquake Information Center:

At least 110 people killed in Samoa, 22 people in American Samoa and seven people on Niuatoputapu, Tonga. Widespread damage to infrastructure at Pago Pago, American Samoa, in many parts of Samoa and on Niuatoputapu, Tonga. Felt (V) at Apia, Samoa and (IV) at Tafuna, American Samoa.

The broad-scale tectonics of the Tonga region are dominated by the relative convergence of the Pacific and Australia plates, with the Pacific plate subducting westward beneath the Australia plate at the Tonga trench. At the latitude of the earthquake of September 29, 2009, the Pacific plate moves westward with respect to the interior of the Australia plate at a velocity of about 86 mm/year. The earthquake occurred near the northern end of a 3,000 km long segment of the Pacific/Australia plate boundary that trends north-northeast.

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I heard that the storm in the Midwest could produce a few thunderstrms across the US. Could that same storm give us some early-season thunderstorms in S. Ontario? I'm supposed to go skiing on Friday in the midst of RAIN.
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NAM forecast surface dewpoints for Wed 6 pm CST:

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186. MTWX
like I was saying earlier.. I cleared my schedule for wednesday just in case...
Member Since: July 20, 2009 Posts: 23 Comments: 1393
185. MTWX
Quoting Jeff9641:


Moisture will increase fast in your area tomorrow thru midday Wed. Don't worry it's coming! Your dew points may reach 60 for a time in Miss.

hopefully... it was 73 today and our dew point didn't get above 40.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Evening all. Just making a quick look-in before heading to bed.

Quoting RitaEvac:
If earthquakes start becoming more frequent and deadly, I might start wondering what the hell is going on. January was Haiti, February was Chile, March so far is Turkey, with other numerous unreported quakes around the world that doesnt cause damage or deaths.
Don't forget this trend started late last year with the quake in the South Seas and another in the Indonesian archipelago in September. Looks like we're in for a year of adjustments, crustwise.

Aussie, that is some mean hail from the recent storm.... amazing size.... esp. in Oz, in my mind.

Anyhoo, I'm off. Will check in this week if and as time permits. I will only add that it's really disgusting to have it be less than 13 degrees difference between Nassau and Southern Ontario in March..... we're likely to hit 58 or lower here tonight... Brrr!

G'Night, all!
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181. MTWX
Quoting Jeff9641:
Wed. looks like a good day for severe wx. East Texas, LA, Arkansas, and Miss will get hammered and some of these tornadoes will be F3 or greater. I don't think Norman has a good handle on these next 2 upper air disturbances.

The air ahead of the system is quite dry. I don't know if there will be enough moisture there for a significant outbreak.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
I dont necessarily disagree with you, but you speak with a lot of certainty
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178. MTWX
Quoting cgmaddog:
Levi, i lived in Cordova a few years ago and remember the saying what us Alaskans call a storm the people in the South name them. I know all of the residents can cope with the weather up there were they cannot fathom the weather you gert up there. I wonder if the road to Anchorage will be closed for a few days due to Avalanche conditions. And yes I do miss Alaska.(currently line in Souht Alabama.)

Mike

I know what you guys are saying, though not to Alaska's extreme. I've never been there, but have always wanted to go. I spent most of my life in Montana but now live in Northern Mississippi.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Quoting cgmaddog:
Levi, i lived in Cordova a few years ago and remember the saying what us Alaskans call a storm the people in the South name them. I know all of the residents can cope with the weather up there were they cannot fathom the weather you gert up there. I wonder if the road to Anchorage will be closed for a few days due to Avalanche conditions. And yes I do miss Alaska.(currently line in Souht Alabama.)

Mike


Oh yeah most people that have lived in the lower 48 their entire lives don't have a clue that the USA can see such winter weather.

I'm not sure how the condition of the road has been since this is the 2nd storm in 3 days, but I would imagine avalanches won't be a huge problem since the snow is all powder. These have been cold storms, which make for large snow-to-liquid ratios and light, fluffy snow. Heavy, wet snow would make avalanches a bigger concern.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
Levi, i lived in Cordova a few years ago and remember the saying what us Alaskans call a storm the people in the South name them. I know all of the residents can cope with the weather up there were they cannot fathom the weather you gert up there. I wonder if the road to Anchorage will be closed for a few days due to Avalanche conditions. And yes I do miss Alaska.(currently line in Souht Alabama.)

Mike
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Webcam on the beach LOL. You may not be able to tell because there's no sand...!



Another looking across the bay at Augustine Volcano. This is daytime by the way.

Member Since: November 24, 2005 Posts: 635 Comments: 26647
Quoting MTWX:

You stay safe there man. Thats really sounds ugly!!


I'm staying snug inside lol. I have been watching my snow-stake and we're busting snow rates of 4 inches per hour right now.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
Levi,
Sounds like Anchorage-ites who wanted to go to Homer on Spring Break this week might want to change their plans.

MTWX,
Good luck with your season.

Gotta run. 'Nite, One and All.
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172. MTWX
Quoting Levi32:
Things are getting very dangerous to be outside in here as winds have switched to the west, allowing lake-effect processes to enhance the snow.


Current Conditions

Homer, Alaska (Airport)
Updated: 21 min 1 sec ago

27 �F
Windchill: 13 �F
Humidity: 93%
Dew Point: 25 �F
Wind: 21 mph from the West

Wind Gust: 30 mph
Pressure: 28.61 in (Rising)
Elevation: 82 ft

You stay safe there man. Thats really sounds ugly!!
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Things are getting very dangerous to be outside in here as winds have switched to the west, allowing lake-effect processes to enhance the snow.


Current Conditions

Homer, Alaska (Airport)
Updated: 21 min 1 sec ago

27 F
Heavy Snow Freezing Fog
Windchill: 13 F
Humidity: 93%
Dew Point: 25 F
Wind: 21 mph from the West

Wind Gust: 30 mph
Pressure: 28.61 in (Rising)
Visibility: 0.0 miles
Elevation: 82 ft
Member Since: November 24, 2005 Posts: 635 Comments: 26647
.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
169. MTWX
That storm came out of the middle of nowhere too. Just glad someone was there to catch and report the tornado
Member Since: July 20, 2009 Posts: 23 Comments: 1393
168. MTWX
Quoting Barefootontherocks:
Thanks for the comeback, MTWX.
Spring has arrived on the Southern Plains.

No kidding.. Just waiting until these storms get within driving distance for me. I already took the time off from work to go spotting.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Thanks for the comeback, MTWX.
Spring has arrived on the Southern Plains.
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166. MTWX
Quoting Barefootontherocks:
Video of tornado in western OKlahoma today. Damaged homes and the county road barn in Hammond. From tv news KFOR OKC
 

looking at the radar from that storm.. wow that was one isolated storm
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Video of tornado in western OKlahoma today. Damaged homes and the county road barn in Hammon. From tv news KFOR OKC
%uFFFD

(PS Greetings, All. 'Nite, All.)
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So I found a transmission for my car.

It's used, has 150,000 miles on it. But my other lasted to 268,000.

So I will have my car back friday, and it costs $1,000 total
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163. MTWX
Dew points are relitively low right now though
Member Since: July 20, 2009 Posts: 23 Comments: 1393
162. MTWX
Quoting atmoaggie:

Getting there...but not quite yet. We'll see in about 48 hours what comes of it.

Just saying.. the current daytime highs ahead of this system are ample enough temperature for severe weather.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Quoting MTWX:

That warm moist air will also allow for a stronger storm system.


Oh I understand what you're saying. I live on the coast and I agree. It was just your wording, "up in the air...moisture" Oh never mind. Only a pun in my head I guess.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
seabreeze developement as we progress into season may prove frequent along gulf states as cooler seabreeze interacts with warmer landmass providing good dynamics into late spring
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Quoting atmoaggie:

Getting there...but not quite yet. We'll see in about 48 hours what comes of it.
problem is the GOM is a cool rtn flow with cool running sst's may prove to be limiting factor for a while till warm up anyway
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Quoting MTWX:

We have the temps here in MS. today our high was into the 70's.

Getting there...but not quite yet. We'll see in about 48 hours what comes of it.
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157. MTWX
Quoting atmoaggie:

The real limiter is the surface temps. When the temp at the surface is less than above, it takes a bunch of lift to get things going and they usually don't turn out to be much.

For example, Dallas about 90 minutes ago. 58 F at the surface, no CAPE to speak of, and a rather large and fairly deep inversion at low levels.


(click for full size)

Cheering for warm temps? That is exactly what this system is lacking in severe potential.

(Here comes Beell to check me...the severe dynamics expert...this is not a jab)

We have the temps here in MS. today our high was into the 70's.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
156. MTWX
Quoting PcolaDan:


HAHAHAHA Read that last line out loud to yourself. :) Isn't that the formula for rain. heehee

That warm moist air will also allow for a stronger storm system.
Member Since: July 20, 2009 Posts: 23 Comments: 1393
Aussie, post 149.
Looks like some heavy stuff there, man.
Sorry to read of all the damage. Must have put some good dings in everything.........
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154. Skyepony (Mod)
C ..LOL~ good one..
Member Since: August 10, 2005 Posts: 164 Comments: 37866
Will the real Robert Ehrlich please stand up? Is it:

A


B


C


D
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Amarillo missing that warmer air aloft. Some CAPE (not scary).


(click for full size)
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Quoting PcolaDan:


HAHAHAHA Read that last line out loud to yourself. :) Isn't that the formula for rain. heehee

The real limiter is the surface temps. When the temp at the surface is less than above, it takes a bunch of lift to get things going and they usually don't turn out to be much.

For example, Dallas about 90 minutes ago. 58 F at the surface, no CAPE to speak of, and a rather large and fairly deep inversion at low levels.


(click for full size)


Cheering for warm temps? That is exactly what this system is lacking in severe potential.

(Here comes Beell to check me...the severe dynamics expert...this is not a jab)
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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.