La Niña by July?

By: Dr. Jeff Masters , 1:42 PM GMT on June 08, 2010

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El Niño rapidly dissipated in May, and we are now very close to entering into a La Niña event, according to the latest sea surface temperature (SST) data over the tropical Eastern Pacific. The weekly SST readings in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", fell to 0.4°C below average on June 7, a full 1°C drop in just one and a half months. This puts us very close to the -0.5°C threshold needed to be considered a La Niña event, according to NOAA's latest El Niño Discussion. The Australian Bureau of Meteorology showed conditions in the Niña 3.4 region were not quite that cool--0.2°C below average for the week ending June 6. Nevertheless, the speed of the collapse of El Niño makes it likely that a La Niña event is on its way this summer, and NOAA's Climate Prediction Center has issued a La Niña watch. Ten of the 23 El Niño models (updated as of May 19) are predicting La Niña conditions for hurricane season. However, as NOAA's Climate Prediction Center commented in their June 3 advisory, a number of the more reliable models are now calling for La Niña to develop this summer. They comment, "there is an increasing confidence in these colder model forecasts, which is supported by recent observations that show cooling trends in the Pacific Ocean and signs of coupling with the atmospheric circulation." Historically, about 35 - 40% of El Niño events are followed by a La Niña within the same year.


Figure 1. Atlantic named storm, hurricane, and intense hurricane activity since the active hurricane period we are in began in 1995. Both La Niña and neutral years have shown similar levels of Atlantic hurricane activity, though the figures are somewhat skewed by the record-setting year of 2005. Background photo: Hurricane Dean, taken from the Space Shuttle.

It is interesting to note that the last time we had a strong El Niño event, in 1998, El Niño collapsed dramatically in May, and a strong La Niña event developed by hurricane season. History appears to be repeating itself, and I predict the emergence of La Niña by July. Since La Niña events tend to bring lower amounts of wind shear to the tropical Atlantic, we can expect a much more active Atlantic hurricane season than usual in 2010. Since 2010 is similar to 1998 in the behavior of the El Niño/La Niña cycle, it is possible that this year's hurricane season could resemble the 1998 Atlantic hurricane season. That year had about 40% above-average activity, with 14 named storms, 10 hurricanes, and 3 intense hurricanes. The season was relatively late-starting, with only one named storm occurring before August 20. Once the season got going, six named storms affected the Gulf of Mexico, including two hurricanes, Earl and Georges, that passed directly over the location of the Deepwater Horizon oil spill.


Figure 2. Tracks of all named storms for the 1998 Atlantic hurricane season.


Figure 3. Typical regional weather anomalies observed during June - August when La Niña conditions are present. The Caribbean tends to be cloudier and wetter than average, but there is typically little change to temperature and precipitations patterns over North America. Image credit: NOAA Climate Prediction Center.

Oil spill update
Light east, southeast, or south winds of 5 - 15 knots will blow today through Saturday, according to the latest marine forecast from NOAA. These winds will keep oil near the beaches of Alabama, Mississippi, and the extreme western Florida Panhandle, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The latest ocean current forecasts from the NOAA HYCOM model are not predicting eastward-moving ocean currents along the Florida Panhandle coast this week, and it is unlikely that surface oil will affect areas of Florida east of Fort Walton Beach. Long range surface wind forecasts from the GFS model for the period 8 - 14 days from now show a southeasterly wind regime, which would prevent any further progress of the oil eastwards along the Florida Panhandle, and would tend to bring significant amounts of oil back to the shores of eastern Louisiana next week. If you spot oil, send in your report to http://www.gulfcoastspill.com/, whose mission is to help the Gulf Coast recovery by creating a daily record of the oil spill.


Figure 4. The oil spill on June 6, 2010 at 8:32pm EDT, as seen by Synthetic Aperture Radar (SAR) imagery from the Italian Cosmo-SkyMed (COnstellation of small Satellites for Mediterranean basin Observation) satellite. A large region of oil was a few miles offshore of Pensacola, Florida. Image credit: University of Miami Center for Southeastern Tropical Advanced Remote Sensing, Rosenstiel School of Marine and Atmospheric Science.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
NOAA's fact sheet on Hurricanes and the Oil Spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
Oil trajectory forecasts from NOAA
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
Synthetic Aperture Radar (SAR) imagery from the University of Miami

"Hurricane Haven" airing again this afternoon
The tropical Atlantic is quiet right now, with no models predicting tropical cyclone development over the next seven days. I'll talk about all this nothingness on my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on Shaun Tanner's blog. Some topics I'll cover on the show:

1) What's going on in the tropics right now--is this typical?
2) New advancements in hurricane science presented at this month's AMS Conference on Hurricanes and Tropical Meteorology last month

Today's show, which will probably be just 1/2 hour, will be at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast, as last week's show was.

I may take a break from blogging Wednesday, as I've got some catching up to do on other duties.

Jeff Masters

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SW Caribbean low makes a reappearance 162-168 hrs (i dont think it ever disappeared, but the mb next to it got taken off for some reason at 150 hrs)

Member Since: July 7, 2008 Posts: 2 Comments: 3237
The GFS seems to be switching primary focus from the wave east of the Antilles islands to the wave already crossing the islands. This wave out in front appears to be the catalyst for a low to develop east of Nicaragua and move up into the Gulf of Honduras. The GFS shows an upper high building over top of this system, providing good ventilation and low wind shear.

18z GFS 108 hour 200mb:

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Quoting Tazmanian:
well now looks like when july start all hell braks loss
Based on what scientific data?
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889. xcool
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At 150 hours on the 18Z GFS run it seems that our SW Caribbean low gets absorbed into a 1008 mb low in the East Pacific.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
EDIT

Development takes place in the EPAC.
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Quoting lazerpointernerd:


You forgot about all the really old fashioned Christian colleges.


There are quite a few of those here too. :P
Member Since: May 27, 2009 Posts: 0 Comments: 4436
Quoting Stormchaser2007:
18z GFS develops an Arthur type storm at around 5 days.

Interesting to say the least.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
well now looks like when july start all hell braks loss
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Quoting jazzygal:
Breaking News on CNN now. Could be over 100,000
barrels of oil leaking into the Gulf.
Is that supposed to be a good thing? Disregarding the large amount before but 100,000 barrels isn't much better.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting gator23:


I think I see a pinhole forecast model eye.


LMAO!
Member Since: July 7, 2008 Posts: 2 Comments: 3237
18z GFS develops an Arthur type storm at around 5 days.

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Quoting mfaria101:
This may be an over-asked question but the El-nino to neutral to La-nina transition confuses me, should we expect more activity because the transition is happening so quickly? or am I simply misreading this blog toady?


sorry to quote myself, but my question is still out there can anyone take a little pity and point out what I cant seem to figure out for myself?
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Quoting MiamiHurricanes09:
Not to disregard the one off the coast of Africa, but the one in the SW Caribbean/Gulf of Honduras seems more probable.


The one in the SW Caribbean makes landfall in 12 hours. So while it's more likely, it's still not likely.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting MrstormX:


In Illinois we have junk, crap, filth and much more lol. But seriously Illinois state schools are underfunded, overcrowded and outdated.


You forgot about all the really old fashioned Christian colleges.
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Breaking News on CNN now. Could be over 100,000
barrels of oil leaking into the Gulf.
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Quoting Levi32:
18z GFS 108 hours: Surface lows west of Africa and in the Gulf of Honduras:

Not to disregard the one off the coast of Africa, but the one in the SW Caribbean/Gulf of Honduras seems more probable.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting HurricaneSwirl:


GFS 120 hours. 1010 mb low


I think I see a pinhole forecast model eye.
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GFS 120 hours. 1010 mb low


EDIT: now that I look even closer, there appears to be a 1011mb low in the sw caribbean as well.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting Drakoen:


Go seminoles!
Well you already know what I'm going to say, just look at my username and avatar. Lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Drakoen:


Go seminoles!

AWAY!
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18z GFS 108 hours: Surface lows west of Africa and in the Gulf of Honduras:

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Quoting HurricaneSwirl:


Yeah, it goes back and forth. I have no idea where it went on 114 hrs.


And now it comes back as a 1010 mb low at 120 hours.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting MiamiHurricanes09:
We have the university of Miami, Florida state university, Florida University, and many more.


In Illinois we have junk, crap, filth and much more lol. But seriously Illinois state schools are underfunded, overcrowded and outdated.
Member Since: May 27, 2009 Posts: 0 Comments: 4436
Quoting atmoaggie:

What about thug-ithically?


Virginia's got that covered with the Stevens' brothers.
Member Since: September 9, 2007 Posts: 36 Comments: 4687
Quoting Stormchaser2007:


English isn't his first language.
Really? Well he speaks it very well.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting MiamiHurricanes09:
We have the university of Miami, Florida state university, Florida University, and many more.


Go seminoles!
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Quoting Hurricanes101:


It doesn't lose it actually, just keeps it weak

still have it as 1012mb at 108 hours


Yeah, it goes back and forth. I have no idea where it went on 114 hrs.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting atmoaggie:

What about thug-ithically?
LOL. That would go to FAU and FIU.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting atmoaggie:

What about thug-ithically?

UM wins internationally
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Quoting MiamiHurricanes09:
We have the university of Miami, Florida state university, Florida University, and many more.


We have UGA and GA Tech... and yeah that's about it ^^;
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting WinterAnalystwx13:


lol


English isn't his first language.
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Quoting ShenValleyFlyFish:


Scholastically or athletically?

Academically, UF is the highest ranked university in the state academically and 47th in the country.
Athletically well you know we have like 1000 championships...

UM Second highest ranking university in the state academically at 50th in the country.
Athletically they have 5 national football titles

FSU well... lets not talk about FSU
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Quoting HurricaneSwirl:
nvm it practically loses the entire thing shortly after. Doesn't look likely.


It doesn't lose it actually, just keeps it weak

still have it as 1012mb at 108 hours
Member Since: March 10, 2010 Posts: 1 Comments: 7367
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting ShenValleyFlyFish:


Scholastically or athletically?

What about thug-ithically?
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Quoting ShenValleyFlyFish:


Scholastically or athletically?
We have the university of Miami, Florida state university, Florida University, and many more.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
nvm it practically loses the entire thing shortly after. Doesn't look likely.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
GFS has 1011mb low at 84 hours on 18Z..

I think that's the lowest yet.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting Weather456:


what's so funny?
No idea...
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting Levi32:


This is a shot of when the GFS starts developing a low off of Africa.

650mb wind speeds and vectors:



At this point the tropical wave is not very amplified or well-defined, so what is supposed to cause this thing to spin up so vigorously and so far south? My guess is that a jet streak associated with the AEJ (African Easterly Jet) moving out over water along with the tropical wave is the catalyst seen by the GFS.

When you have a stream of fast-moving air, it causes the air on either side of it to have vorticity, giving it a tendency to spin. Think of it like a swift-flowing stream of water flowing through a valley. If it is wide, the stream will often flow fastest in the deep currents at the middle of the stream, but near the sides of the stream the speed of the water slows down in the shallow areas, and often starts spinning in little eddies due to the difference in the flow rate.

It is the same with streams of air. The east-flowing AEJ causes areas of positive vorticity on its south side, which makes the air tend to spin cyclonically (counter-clockwise). The GFS here is forecasting a jet streak (a core of strong winds within a jetstream) to move out over the Atlantic along with the tropical wave in a couple days. This jet streak doesn't last very long over the water before dissipating, but it seems to provide enough positive vorticity on its south side to get a low to spin up along the tropical wave on the model.


very good obs
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Quoting gator23:


No we have Universities, good ones too. Higher ranked than any Alabama State Universities


Scholastically or athletically?
Member Since: September 9, 2007 Posts: 36 Comments: 4687
Quoting WinterAnalystwx13:


lol


what's so funny?
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Member Since: May 27, 2009 Posts: 0 Comments: 4436
here is latest 72 hr northern hemisphere global forecast system depiction

Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting SouthALWX:

Florida has colleges??


No we have Universities, good ones too. Higher ranked than any Alabama State Universities

UF Rank 47 (win)
UA Rank 96 (fail)
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Quoting Levi32:
The interesting thing about the vigorous wave the GFS develops in a couple days is that such a vigorous wave does not exist at the moment, from what I can tell. There is a tropical wave near the western border of Ghana, but it is not very amplified, and over the last 24 hours has had a poor satellite signature.

The GFS develops this wave south of the AEJ at 5N, which is pretty far south to spin something up off of Africa. The model seems to show a vort max suddenly spinning up along the wave axis south of the AEJ, likely due to the strong positive zonal vorticity gradient on the south side of the AEJ forecasted by the GFS to move out over the eastern Atlantic with the tropical wave.



This is a shot of when the GFS starts developing a low off of Africa.

650mb wind speeds and vectors:



At this point the tropical wave is not very amplified or well-defined, so what is supposed to cause this thing to spin up so vigorously and so far south? My guess is that a jet streak associated with the AEJ (African Easterly Jet) moving out over water along with the tropical wave is the catalyst seen by the GFS.

When you have a stream of fast-moving air, it causes the air on either side of it to have vorticity, giving it a tendency to spin. Think of it like a swift-flowing stream of water flowing through a valley. If it is wide, the stream will often flow fastest in the deep currents at the middle of the stream, but near the sides of the stream the speed of the water slows down in the shallow areas, and often starts spinning in little eddies due to the difference in the flow rate.

It is the same with streams of air. The east-flowing AEJ causes areas of positive vorticity on its south side, which makes the air tend to spin cyclonically (counter-clockwise). The GFS here is forecasting a jet streak (a core of strong winds within a jetstream) to move out over the Atlantic along with the tropical wave in a couple days. This jet streak doesn't last very long over the water before dissipating, but it seems to provide enough positive vorticity on its south side to get a low to spin up along the tropical wave on the model.
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The model at first didn't supported development due to the lost of convection after emerging.
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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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