El Niño gone; La Niña on the way?

By: Dr. Jeff Masters , 5:33 PM GMT on February 28, 2007

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The El Niño event of 2006-2007 is over. Ocean temperatures in the Equatorial Eastern Pacific have cooled rapidly over the past four weeks, resulting in near-normal water temperatures and an end to the El Niño event that began in September 2006. By definition, an El Niño episode occurs when Sea Surface Temperatures (SSTs) are at least +0.5ºC above normal in the region 120°W-170°W and 5°S-5°N (called the Niño 3.4 region). SSTs in this region reached +0.5ºC above normal in September, and fell below +0.5ºC above normal in late January. A time series of the departure of SST from normal (Figure 1) shows the rapid cooling over the past four weeks to near-normal values in this El Niño 3.4 region (black box on the plots).


Figure 1. Departure of Sea Surface Temperatures from normal for the past four weeks. The black box marks the region 120°W-170°W and 5°S-5°N (called the Niño 3.4 region). Note the rapid cooling to below-normal values in portions of this box. Image credit: NOAA Climate Prediction Center.

What does this mean for Atlantic hurricane season?
The demise of El Niño is bad news for those living along the hurricane-prone areas of the Atlantic coast. El Niño conditions tend to suppress Atlantic hurricane activity, as occurred in the 2006 hurricane season. It is extremely unlikely we will see a return to El Niño conditions this fall. A decay of El Niño this time of year is very rarely followed by a resurgence later in the year, and only one of the 20 or so computer models used to forecast El Niño is forecasting this to happen this year. It is much more likely that we will see a full-fledged La Niña episode develop. Indeed, La Niña may be already be well on its way--NOAA chief Conrad Lautenbacher remarked in a press release today, "we're seeing a shift to the La Nina, it's clearly in the data". He was refering to a large pool of cooler than normal waters that has developed in recent weeks in the sub-surface waters of the Equatorial Eastern Pacific. This is a prime situation for a La Niña to develop, and several of the long-range computer models are predicting La Niña conditions for the coming hurricane season (Figure 2). These models are not very reliable, however, and it is equally probable that we will see El Niño-neutral conditions--the absence of either a La Niña or El Niño--for the coming hurricane season. La Niña conditions usually cause Atlantic hurricane seasons that are much more active than average, so El Niño-neutral conditions would probably be more welcome than a La Niña. Remember, though, that the worst hurricane season on record--the infamous Hurricane Season of 2005--occurred with El Niño-neutral conditions. I am expecting a much more active hurricane season than the mild season of 2006 as a result of this month's demise of El Niño.


Figure 2. Computer model forecasts of the departure of SST from normal in the region 120°W-170°W and 5°S-5°N (called the Niño 3.4 region). Temperatures +0.5ºC above normal in this region indicate an El Niño episode; temperatures -0.5ºC below normal indicate an La Niña. Three of the 14 models plotted predict La Niña conditions during the upcoming hurricane season (ASO, August-September-October), one model predicts El Niño conditions, and the other ten predict El Niño-neutral conditions. Image credit: International Research Institute ofr Climate and Society.

I'd like to welcome our new featured blogger, Mike Theiss! Mike is a professional weather photographer and storm chaser, and will be sharing his awesome storm photos with us for the coming tornado season. He also documents all landfalling U.S. hurricanes (check out his amazing Katrina videos), so tune in this hurricane season to his blog!

Jeff Masters

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214. hurricant
1:14 AM GMT on March 02, 2007
thanks pottery remember it is a question and an attempt to form a question i just thought sand sandstorm data that i looked at was inconclusive so i asked .
213. franck
10:59 PM GMT on March 01, 2007
Much storm damage in SE AL. At least 9 dead, some missing. Full morgue set up in Enterprise.
Member Since: August 30, 2005 Posts: 0 Comments: 1150
212. franck
10:41 PM GMT on March 01, 2007
At least 8 dead in Enterprise, AL from super tornado, just a few miles south of here.
Member Since: August 30, 2005 Posts: 0 Comments: 1150
211. pottery
10:29 PM GMT on March 01, 2007
Yikes, Margie, Stay inside !
Member Since: October 24, 2005 Posts: 0 Comments: 24307
210. pottery
10:27 PM GMT on March 01, 2007
Hurricant, I dont think it is true to say that W. African weather conditions affect Nino/Nina. I think it is pretty well agreed that the opposite is true.i.e. , that Nino/Nina affect W.African weather. However, W African weather affects Atlantic weather, so the cycle goes on.
Member Since: October 24, 2005 Posts: 0 Comments: 24307
209. MargieKieper
10:22 PM GMT on March 01, 2007
I'm not sure how often this happens, but...the Gov of Iowa has declared the entire state a disaster area. :-)

Here's an image looking out my door, south of the Twin Cities, where I shoveled just two hours ago (the round table that used to have the "snow cake" blew away):

Time to shovel...again
Member Since: June 15, 2006 Posts: 181 Comments: 355
208. pottery
10:19 PM GMT on March 01, 2007
,,er, sorry for that weird post.
Member Since: October 24, 2005 Posts: 0 Comments: 24307
207. pottery
10:18 PM GMT on March 01, 2007
>


......because last season, ALL conditions were generally favourable with the trop. waves coming off the Continent, and the SAL was the primary destroyer.









Member Since: October 24, 2005 Posts: 0 Comments: 24307
206. pottery
10:15 PM GMT on March 01, 2007
Hi all. So is there a forecast for Sahara Weather this season, and what the SAL will be like in June, july ect ??
Member Since: October 24, 2005 Posts: 0 Comments: 24307
205. Skyepony (Mod)
10:00 PM GMT on March 01, 2007
Agreed Michael.. Katrina as some others traveled over here as naked swirls, finally shaking out their dust pretty close to the USA. If they would have formed sooner, better chances they'd of turned N & out to sea.

At the time I thought 2005 was considered a record dust year.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
204. Skyepony (Mod)
9:58 PM GMT on March 01, 2007
NOAA has some breaking news..

DARKNESS ADDS DANGER TO ONGOING SEVERE WEATHER OUTBREAK
Now Is the Time to Ensure Your NOAA Weather Radio is Operating




click to make bigger.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
202. hurricant
9:51 PM GMT on March 01, 2007
So could it be said that( El nino La Nina Vs Sandstorms) that they are related yet opposing forces in the atlantic storm cycles.. Remember that i am no scientist, however, I live in Miami, was affected by wilma( lost the old roof)and i was presented information suggesting MT MUrapi eruption last year caused the sandstorm. Yet i Have read that West african drought is tied to El nIno cycles. Can anyone clarify
201. Skyepony (Mod)
9:47 PM GMT on March 01, 2007
For the 2005 hurricane season, which broke records in the Atlantic, however, dust activity was moderate, indicating yet another level of potential complexity to the dust-hurricane interactions, which the researchers are continuing to investigate, Evan says. During that year’s hurricane season, the researchers noted an increase in dust from the African coast, and a dearth of hurricanes forming in the middle of the Atlantic. Instead, they “kind of got pushed closer to the United States,” he says. Therefore, an indirect effect may also occur, in which the dust may dampen storm formation in the middle Atlantic, but not prevent them from forming farther west.

Dust is an inhibiting factor, not a savior.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
200. weatherboykris
9:40 PM GMT on March 01, 2007
hurricant...the El Nino/La Nina does not directly affect those dust clouds.The dust clouds have a major hampering impact on hurricanes.
Member Since: December 9, 2006 Posts: 125 Comments: 11346
199. ProgressivePulse
9:38 PM GMT on March 01, 2007
Hummmm the map on the welcome page looks like a Christmas Tree. Little stormy up in the mid-section.
Member Since: August 19, 2005 Posts: 5 Comments: 5396
198. MisterPerfect
9:32 PM GMT on March 01, 2007
I think it definetly had something to with it ( dust vs hurricane activity )
Member Since: November 1, 2006 Posts: 71 Comments: 20137
197. hurricant
9:05 PM GMT on March 01, 2007
Good day .. Does anyone know the Prominence of El nino la nina on the african sandstorm that made its way to florida last year, and was it the greatest factor in killing last years atlantic season
196. bigdaddyo
9:02 PM GMT on March 01, 2007
Thanks for the info on El Nino! I read about the severe outbreak expected in the lower Ohio River valley, so far the storms that had reached severe limits this morning in Missouri have weakened. So we here in KY may be spared.
Member Since: June 20, 2005 Posts: 37 Comments: 26
195. ricderr
8:28 PM GMT on March 01, 2007
1

Member Since: June 27, 2006 Posts: 673 Comments: 21638
194. MisterPerfect
8:18 PM GMT on March 01, 2007
Predicting hurricane strength closer

BY MARTIN MERZER
MiamiHerald.com

A new scientific study reveals important clues about the fluctuating power of hurricane winds and offers the tantalizing possibility that forecasters soon might solve their most vexing problem:

How to better predict when storms will grow more powerful -- and how to anticipate the perilous ''rapid intensification'' of some hurricanes as they approach populated regions.

Example A: Hurricane Andrew, just before it crashed into South Miami-Dade County in 1992. Example B: Hurricane Charley, just before it flattened much of Southwest Florida in 2004.

''For everybody who has to make real decisions in which property and some lives are at stake, this is a huge advance,'' said Hugh Willoughby, a professor at Florida International University and former director of the federal government's Hurricane Research Division on Virginia Key.

Shuyi Chen, an associate professor of meteorology at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, said the breakthrough soon should produce better intensity forecasts.

''We're trying to get the state of the art to move forward,'' she said.

Chen is one of four co-authors of the peer-reviewed study, to be published Friday in the prestigious journal Science. The lead author is Robert Houze Jr., a professor of atmospheric science at the University of Washington.

Based largely on research conducted by the crews of three hurricane hunter aircraft, the study revealed the mechanics of a phenomenon called ''eye wall replacement'' and found links between it and the ebb and flow of wind intensity.

The eye wall is the thick ring of clouds that surrounds a hurricane's eye and generates the most powerful -- and destructive -- winds.

Eye wall replacement occurs when those clouds disintegrate, temporarily weakening a storm, only to be replaced by another eye wall that eventually becomes as strong or even stronger than the first.

And that is what keeps forecasters awake at night -- the difficulty in predicting those changes and the possibility that a storm will unexpectedly mushroom in power just before it hits land.

Desperatedly seeking to improve those forecasts, scientists have been trying to develop extremely sensitive computerized models that can respond to relatively small changes in the atmosphere in and around hurricanes.

''You needed to have computer models that can tell you not only what's happening now, but what will be happening several days from now,'' Chen said.

So, during simultaneous flights by three hurricane hunter planes that darted in and out of Katrina, Rita and Ophelia in 2005, researchers mapped small-scale changes in outlying rain bands and in a region of dry air just outside the eye wall called a ``moat.''

Then they were able to link those changes to the eye wall replacement cycle and to changes in wind intensity.

The scientists already have developed a forecast model based on their research, and they devised a new way to direct aircraft as crews examine these atmospheric features.

Now, the researchers are hoping to add their tool to the workbench of forecasters. The National Atmospheric and Oceanic Administration's fiscal 2008 budget proposal includes an extra $2 million for hurricane intensity research.

''The adoption of real-time targeting of aircraft onto small-scale storm features likely to be associated with storm-intensity change could provide timely input that would improve operational forecasts of hurricane intensity,'' the report concluded.

This is important because advances in intensity forecasts have lagged far behind improvements in track forecasts.

Some examples:

• Twenty-four hours before Andrew smashed into South Florida as a Category 5 hurricane, it was predicted to reach the area as a Category 3.

• A day before Charley hit Captiva Island as a near-Category 5 hurricane, it was predicted to strike the region as a Category 3.

• Worst of all, Hurricane Mitch suddenly exploded from a Category 3 storm to a Category 5 in October 1998, killing thousands in Honduras, Nicaragua and Guatemala.

''We know that eye wall replacement affects intensity, but we needed to know what affects the timing of that,'' said Willoughby, who served as an official reviewer of the the report and wrote a commentary that also appears in Friday's edition of Science.

''If you get landfall while the storm is in the weakening stage, that's good,'' he said. ``If you get it in the intensifying stage, you get Andrew.''
Member Since: November 1, 2006 Posts: 71 Comments: 20137
193. Skyepony (Mod)
7:09 PM GMT on March 01, 2007
There is a mistake in the wind section about a person being trapped. It's in there under 2 locations.
Member Since: August 10, 2005 Posts: 162 Comments: 37829
192. Thunderstorm2
7:06 PM GMT on March 01, 2007
He/She was in a Mobile Home. They must not have seen it coming.
Member Since: December 22, 2006 Posts: 129 Comments: 7608
191. Skyepony (Mod)
7:04 PM GMT on March 01, 2007
1 Fatality (storm report page)
Member Since: August 10, 2005 Posts: 162 Comments: 37829
190. lightning10
6:59 PM GMT on March 01, 2007
I think the wild fires this year in So Cal will be the big story this summer. I beleave again people have there hopes way to high for this hurricane season. Yes there will be more then last year but nothing like 2005.

Inyo I agree 100%. This so called El Nino was a sick joke. I know 1/3 El Ninos are dry but never this dry.
Member Since: November 24, 2005 Posts: 41 Comments: 630
187. weatherboykris
5:26 PM GMT on March 01, 2007
how you doing H23?
Member Since: December 9, 2006 Posts: 125 Comments: 11346
186. hurricane23
5:10 PM GMT on March 01, 2007
Good afternoon kris!
Member Since: May 14, 2006 Posts: 8 Comments: 13786
185. weatherboykris
4:36 PM GMT on March 01, 2007
Good morning all
Member Since: December 9, 2006 Posts: 125 Comments: 11346
184. Skyepony (Mod)
4:33 PM GMT on March 01, 2007
NOAA News On La Niña

LA NIÑA MAY SOON ARRIVE

By this image from Tuesday ENSO is crashing
Member Since: August 10, 2005 Posts: 162 Comments: 37829
183. Tazmanian
4:24 PM GMT on March 01, 2007
WU mail call for dr m
Member Since: May 21, 2006 Posts: 5091 Comments: 115080
182. Inyo
3:51 PM GMT on March 01, 2007
yeah for all the good this El Nino did for california, bring on the La Nina instead. Last year was La Nina and at least we got some rain that year.
Member Since: September 3, 2002 Posts: 42 Comments: 873
181. Patrap
3:45 PM GMT on March 01, 2007
up da river..LOL..Link
Member Since: July 3, 2005 Posts: 424 Comments: 128259
180. Patrap
3:43 PM GMT on March 01, 2007
You can also go here...for view.Link
Member Since: July 3, 2005 Posts: 424 Comments: 128259
179. Patrap
3:42 PM GMT on March 01, 2007
Outside...Link
Member Since: July 3, 2005 Posts: 424 Comments: 128259
178. lightning10
3:20 PM GMT on March 01, 2007
LA looks like its going to go into the books with the second dryest rainy season on record...

Statement as of 5:30 am PST on March 1, 2007

… It is the second driest rain season to date in downtown Los
Angeles…

Downtown Los Angeles received 0.92 inches of rain during the month
of February. Although this was not nearly one of the driest
februaries since official records began… rainfall for the
month was well below the normal of 3.68 inches. February is…
on average… the wettest month of the year in Los Angeles…
and believe it or not… with just 0.92 inches of rain… it
was the wettest month of the rain year so far. In fact… it
was the wettest month since April 2006.

This season is currently the second driest rain season to date
in downtown Los Angeles since records began in 1877. Since the
beginning of the water year… which began July 1 2006… downtown
Los Angeles has received a paltry 2.42 inches of rain. That is
just 22 percent of what is normal through the end of February.
It is also 8.38 inches below the normal precipitation to date…
which is 10.80 inches.

March… with an average rainfall of 3.14 inches… can be a very
wet month in Los Angeles… as in 1884 when 12.36 inches of rain
fell. However… average rainfall drops off sharply in April to
0.83 inches… then to 0.31 inches in may… and just 0.06 inches
in June. Normal seasonal rainfall at downtown Los Angeles is
15.14 inches.

Seasons with the least rainfall from July 1st through February
28th (except 29th in leap years) are listed below.

During the driest season ever… the 2001-2002 season…
precipitation from July 1st 2001 to February 28th was 3.95
inches.
Member Since: November 24, 2005 Posts: 41 Comments: 630
177. hurricane23
2:52 PM GMT on March 01, 2007
Yea STL i just noticed that thanks by the way have you seen this imagehosting site it allows you to add a discription to the image i use it often.Postimage.org

Example...

Member Since: May 14, 2006 Posts: 8 Comments: 13786
176. ricderr
2:48 PM GMT on March 01, 2007
Just in case 2007 turns out to be another once in a lifetime year as 2005..may i suggest some names so we don't need to use the greek alphabet......

Ivanna Getouttahere
Haywood Jablomahowzdowne
Hal Deep
Fimah Letuzdowne
Konoff d' Strockshun
Yagot Powryet
Noruf Onmaihowz
Duck N'Cuver
Kissur Asgoodby
Weir Gonners
Member Since: June 27, 2006 Posts: 673 Comments: 21638
175. ricderr
2:45 PM GMT on March 01, 2007
Today.....is...."Enjoy the Humor Day"...i'll help provide the humor..the clowns..preceed me



Wilma, Wilma Flintstone
Made us a modern stone-age family
From the town of Can-Cun
She's a witch right out of history

Let's join with the looters down the street
They know that the prices can't be beat

When it's Wilma
Wilma Flintstone
Have a yabba dabba doo time,
A hur-ra-cane time
We'll have a lights out time.
(To Close the Show)

Someday, maybe FEMA'll join the fight
And the generators'll be quiet for the night

When it Wilma Flintstone
Have a yabba dabba doo time,
A hur-ra-cane time
We'll have a lights out time.
Member Since: June 27, 2006 Posts: 673 Comments: 21638
173. hurricane23
2:42 PM GMT on March 01, 2007
Ive got comcast highspeed and it still takes a while to load up.Imageshack is an option for those kind of images.
Member Since: May 14, 2006 Posts: 8 Comments: 13786
172. ricderr
2:41 PM GMT on March 01, 2007
Ahhh..always count on STL to state the obvious...great job
Member Since: June 27, 2006 Posts: 673 Comments: 21638
170. hurricane23
2:34 PM GMT on March 01, 2007
bigdaddyo here are a few sights that have been good to me.

1-La nina and el nino resources
2-Madden-Julian Oscillation
3-CPC-MJO page
4-MJO-Research
Member Since: May 14, 2006 Posts: 8 Comments: 13786
169. ricderr
2:31 PM GMT on March 01, 2007
Where's gulfscotsman when we need him?
Member Since: June 27, 2006 Posts: 673 Comments: 21638
168. ricderr
2:30 PM GMT on March 01, 2007
whoa....we can't paste images here anymore?....come on.....let's get real...when the host asks them to stop...fine....soon..people will be saying...let's stay on topic..LMAO
Member Since: June 27, 2006 Posts: 673 Comments: 21638
167. Patrap
2:29 PM GMT on March 01, 2007
60 hr GOM temp Forecast loop..Link
Member Since: July 3, 2005 Posts: 424 Comments: 128259
166. Patrap
2:24 PM GMT on March 01, 2007
heres a loop..GOMLink
Member Since: July 3, 2005 Posts: 424 Comments: 128259
165. HurricaneMyles
2:23 PM GMT on March 01, 2007
Bigdaddyo...There are a lot of sites that give good explanations on El Nino and La Nina. But basically El Nino happens when the normal easterly trade winds in the equatorial pacific stop blowing as strong, and even reverse. Normal trade winds causes the water to move from E to W, and off the S. American coast. Water moving away from the coast pulls colder water from up from the depths. Since El Nino slows/stops the trade winds, the water stops flowing W and pulling up cold water. That, along with the fact that stronger winds cause more evaporation which cools water, causes the pacific to warm.

La Nina is the opposite, the trade winds blow stronger, which cools the water more the usual.
Member Since: January 12, 2006 Posts: 5 Comments: 827
164. hurricane23
2:19 PM GMT on March 01, 2007
Morning guys...

Were now up to the half way point of this offseason and before you know it all starts again.Use this time to prepare and consider were you would go if youre was asked to evacuate dont wait till june 1.Hopefully this season will be kind to the U.S. Adrian

1-Create a Free Hurricane Plan
2-Are you ready?

Patrap you might want to create a thumbnail for that image.thanks
Member Since: May 14, 2006 Posts: 8 Comments: 13786

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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.

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