La Niña drawing to a close

By: Dr. Jeff Masters , 3:39 PM GMT on February 27, 2012

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La Niña, the cooling of the equatorial Pacific waters off the coast of South America that has dramatically affected our weather for most of the past two years, is almost done. Sea surface temperatures (SSTs) over the tropical Eastern Pacific in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", have warmed rapidly over the past two weeks, and were 0.4°C below average on February 27. This is slightly warmer than the -0.5°C threshold to be considered La Niña conditions, and is the first time since early August that La Niña conditions have not been present. It is likely that SSTs will continue to warm during March and April, and NOAA's Climate Prediction Center is predicting that they will declare an official end to La Niña sometime between March and April. A moderate to strong La Niña began in the summer of 2010, weakened briefly during May - July 2011 to neutral status, then re-intensified to a borderline weak/moderate La Niña from August 2011 - January 2012.


Figure 1. Comparison of the sea surface temperature departure from average from January 4 and February 22, 2012, over the tropical Eastern Pacific. During January, a large region of the ocean was more than 0.5°C cooler than average, meaning a La Niña event was present. Beginning in mid-February, waters warmed rapidly from east to west along the Equator, signaling and end to the La Niña event. Image credit: NOAA.

The forecast: neutral or El Niño conditions by fall
The period March - May is the typical time of year that El Niño or La Niña events end, and it is common for the opposite phenomena to take hold by fall. Since 1950, there have been twelve La Niña events that ended during the first half of the year; during six of those years (50%), an El Niño event formed in time for the August - September - October peak of hurricane season. The official forecast from Columbia University's IRI and NOAA's Climate Prediction Center calls for a 31 - 32% chance of an El Niño event during the 2012 Atlantic hurricane season. El Niño conditions tend to suppress Atlantic hurricane activity by creating high levels of wind shear that tends to tear hurricanes apart. Given the relatively high chance of an El Niño event this fall, plus ocean temperatures over the tropical Atlantic that are cooler than we saw in 2011 and 2010, I doubt we'll see an Atlantic hurricane season as active as the ones in 2010 and 2011 (nineteen named storms both years, third busiest seasons on record.) The demise of La Niña also means that global temperatures should begin to approach record warm levels by the end of the year. The cool waters of a La Niña event keep global temperatures cooler than average.


Figure 2. Computer model forecasts of El Niño/La Niña made in mid-February 2012. The forecasts that go above the red line at +0.5°C denote El Niño conditions; -0.5°C to +0.5°C denote neutral conditions, and below -0.5°C denote La Niña conditions. Most of the computer models are predicting neutral or El Niño conditions during the fall peak of the Atlantic hurricane season. Image credit: Columbia University's IRI.

I'll have a new post by Wednesday.

Jeff Masters

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Quoting GeorgiaStormz:


Possible Tornado


That's just a wall cloud, imo.
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Quoting hurricanehunter27:
Could be seeing that most likely all it will be picking up is dirt.Very rural area. Also the little appendage the storm still has is interesting. Also this storm seems to be getting some insane inflow.
Things seem to have calmed, but you bring up a good point. Even a little appendage, if it hit's the right spot, can have quite an effect.
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Nice storms tonight!
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Really interesting interview about the aftermath of 2011 Japanese earthquake on NPR right now... been going on for about half an hour now. there's supposed to be some sort of documentary on it later tonight I believe.
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Quoting TropicalAnalystwx13:
The first February Nebraska tornado on record...snow is still on the ground, and temperature was 47F.



That deserves a:




DRAMATIC CHIPMUNK!!!!
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Quoting hurricanehunter27:
What I am looking at:

Yes, I see it. =P

A small tornado has been produced by it south of Hutchinson.
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These night storms suck!
I cant see anything from the spotters
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Amazing how where I am in Breckenridge, Colorado, it is a blizzard, while in Nebraska, a tornado amidst snow on the ground occurred. All with the same system.
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Quoting TropicalAnalystwx13:
The first February Nebraska tornado on record...snow is still on the ground, and temperature was 47F.



What a crazy blizzard to be in! :-)
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Quoting hurricanehunter27:
Yes but its not falling apart, people who are not looking at the radar will get the message that this storm is no longer dangerous. Also just got new radar frame, this storm is epic.
What I am looking at:
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Quoting TropicalAnalystwx13:

It may be cycling, but it's not impressive looking anymore. The hook is gone and rotation is weak and very broad.

Yes but its not falling apart, people who are not looking at the radar will get the message that this storm is no longer dangerous. Also just got new radar frame, this storm is epic.
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Quoting TropicalAnalystwx13:
The first February Nebraska tornado on record...snow is still on the ground, and temperature was 47F.

Oh no!.It is the end of the world!.It would be lovly if someone caught it on camra and the tornado was whit except for gray like always.
Member Since: August 14, 2010 Posts: 10 Comments: 17097
Quoting hurricanehunter27:
Sry but no this storm is still very strong, still has some good rotation and seems to be cycling.

It may be cycling, but it's not impressive looking anymore. The hook is gone and rotation is weak and very broad.

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Quoting TropicalAnalystwx13:
Storm is falling apart now.
Sry but no this storm is still very strong, still has some good rotation and seems to be cycling.
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The first February Nebraska tornado on record...snow is still on the ground, and temperature was 47F.

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Good evening everyone.Good to see all the same and a few new ones this year.
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Quoting Ameister12:

I hope that's not a debris ball.
Could be seeing that most likely all it will be picking up is dirt.Very rural area. Also the little appendage the storm still has is interesting. Also this storm seems to be getting some insane inflow.
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Quoting AtHomeInTX:


With a few exceptions, most recently Ike, Texas doesn't get a lot of those long trackers. But I guess when we do they're doozies! Then again, I'm just going off of my own study of tracks. Some began just at the Caribbean so they just may not have been seen until then.



Poor Texas and Florida they seem to always get the worst hurricanes.And speaking of Florida they better watch out...
Member Since: August 14, 2010 Posts: 10 Comments: 17097
Storm is falling apart now.
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Quoting KoritheMan:


I'm still not that concerned with the Pacific. Though I agree that the anomalous cooling of the MDR could curb tropical cyclone potential, especially farther east toward west Africa, where the ongoing drought could limit Cape Verde hurricanes. On the other hand, such a setup would allow for tropical waves to develop farther west, giving them less prospect for recurvature into the westerlies.


With a few exceptions, most recently Ike, Texas doesn't get a lot of those long trackers. But I guess when we do they're doozies! Then again, I'm just going off of my own study of tracks. Some began just at the Caribbean so they just may not have been seen until then.



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Quoting hurricanehunter27:
Really starting to look nasty.

That's a mean looking hook...
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About time. >:(

379
WFUS53 KICT 290030
TORICT
KSC155-290100-
/O.NEW.KICT.TO.W.0001.120229T0030Z-120229T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WICHITA KS
630 PM CST TUE FEB 28 2012

THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A

* TORNADO WARNING FOR...
EASTERN RENO COUNTY IN SOUTH CENTRAL KANSAS...

* UNTIL 700 PM CST

* AT 626 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
DANGEROUS STORM WAS LOCATED NEAR ARLINGTON...OR 15 MILES NORTH OF
KINGMAN...AND MOVING NORTHEAST AT 60 MPH.

* LOCATIONS IMPACTED INCLUDE...
HUTCHINSON...PARTRIDGE...SOUTH HUTCHINSON...BUHLER...YODER...
WILLOWBROOK AND HUTCHINSON AIRPORT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT
WAS IN EFFECT FOR THE SAME AREA.

&&

LAT...LON 3817 9795 3817 9770 3813 9770 3796 9771
3776 9813 3790 9828
TIME...MOT...LOC 0030Z 229DEG 53KT 3790 9811
HAIL 1.75IN

$$
Member Since: Posts: Comments:
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WICHITA KS
630 PM CST TUE FEB 28 2012

THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A

* TORNADO WARNING FOR...
EASTERN RENO COUNTY IN SOUTH CENTRAL KANSAS...

* UNTIL 700 PM CST

* AT 626 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
DANGEROUS STORM WAS LOCATED NEAR ARLINGTON...OR 15 MILES NORTH OF
KINGMAN...AND MOVING NORTHEAST AT 60 MPH.

* LOCATIONS IMPACTED INCLUDE...
HUTCHINSON...PARTRIDGE...SOUTH HUTCHINSON...BUHLER...YODER...
WILLOWBROOK AND HUTCHINSON AIRPORT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT
WAS IN EFFECT FOR THE SAME AREA.
Member Since: Posts: Comments:
Quoting Ameister12:
Fortunately, there are chasers near this storm, but it still needs a tornado warning.
What in gods name is the NWS doing? There may be a tornado that has been on the ground for 7 mins.
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Quoting hurricanehunter27:
Really starting to look nasty.

I hope that's not a debris ball.
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Fortunately, there are chasers near this storm, but it still needs a tornado warning.
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502. Skyepony (Mod)
Quoting tampahurricane:
Just bought the Davis Vantage Pro 2 weather station. Im here in the Tampabay area so I will be gladly posting local conditions on here in the near future :)


That's a nice one. Upload your PWS data to WU & you get free membership, data history storage, a forecast for your backyard & graphs..
Member Since: August 10, 2005 Posts: 175 Comments: 38212
Really starting to look nasty.
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Quoting hurricanehunter27:
I also believe this storm need to be tornado warned soon. Showing signs of rotation.

Soon? NO! It needed to be warned on five minutes ago. Very pronounced rotation with a hook echo and likely tornado.

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I also believe this storm need to be tornado warned soon. Showing signs of rotation.
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Belleville seems to have taken a direct hit. Hope nothing was on the ground.
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all we can do is watch and look for clues
Member Since: July 15, 2006 Posts: 174 Comments: 54483
Keep an eye on the Omaha Twister Chasers. They might be positioning themselves for an intercept.
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Jim Cantore was just talking about Friday with Forbes, and used the words "Tornado" and "Outbreak" together. Forbes has already given a value of 5 out of 10.
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Quoting KoritheMan:


Yeah, probably.


we still will see a few cv systems
come forth but with sst's low as they are
may not be many
but even so
we still have 3 months left to see
how sst's rebound in the MDR
i think the nino region will be above normal by late aug
and that will shut it down as fast as it gets started maybe who knows
Member Since: July 15, 2006 Posts: 174 Comments: 54483
"For jealousy and envy is dumb ones tools,so washingtonian115 says nothing and keeps her cool". "Now revenge is not a mention that the D.C women is on just forgivness required for the wrong that's done".
Member Since: August 14, 2010 Posts: 10 Comments: 17097
Tornado Warning reissued!

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
549 PM CST TUE FEB 28 2012


KSC157-290000-
/O.CON.KTOP.TO.W.0001.000000T0000Z-120229T0000Z/
REPUBLIC-
549 PM CST TUE FEB 28 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM CST FOR
SOUTHWESTERN REPUBLIC COUNTY...

AT 544 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM WITH STRONG ROTATION CAPABLE OF
PRODUCING A TORNADO. THIS STORM WAS LOCATED NEAR NORWAY...OR 11
MILES NORTHWEST OF CONCORDIA...MOVING NORTHEAST AT 45 MPH.

LOCATIONS IMPACTED INCLUDE...
NORWAY.
SCANDIA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF A TORNADO APPROACHES...GO TO A BASEMENT OR SEEK SHELTER IN A
HALLWAY OR CLOSET ON THE LOWEST FLOOR OF THE BUILDING. USE BLANKETS
OR PILLOWS TO COVER YOUR HEAD AND ALWAYS STAY AWAY FROM WINDOWS. IF
YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY BUILDING. AS A LAST
RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW SPOT AND COVER YOUR
HEAD.

STAY TUNED TO NOAA WEATHER RADIO OR LOCAL MEDIA OUTLETS FOR THE
LATEST SEVERE WEATHER INFORMATION.

&&

LAT...LON 3987 9781 3979 9759 3965 9761 3965 9793
3979 9794
TIME...MOT...LOC 2349Z 229DEG 39KT 3971 9776
HAIL <.75IN

$$
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It's back. =)

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TOPEKA KS
604 PM CST TUE FEB 28 2012

THE NATIONAL WEATHER SERVICE IN TOPEKA HAS ISSUED A

* TORNADO WARNING FOR...
NORTHEASTERN REPUBLIC COUNTY IN NORTH CENTRAL KANSAS...

* UNTIL 630 PM CST

* AT 603 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM WITH STRONG ROTATION CAPABLE OF PRODUCING A
TORNADO. THIS SEVERE STORM WAS LOCATED 3 MILES SOUTHWEST OF
BELLEVILLE...MOVING NORTHEAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
BELLEVILLE...
MUNDEN...
NARKA...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF A TORNADO APPROACHES...GO TO A BASEMENT OR SEEK SHELTER IN A
HALLWAY OR CLOSET ON THE LOWEST FLOOR OF THE BUILDING. USE BLANKETS
OR PILLOWS TO COVER YOUR HEAD AND ALWAYS STAY AWAY FROM WINDOWS. IF
YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY BUILDING. AS A LAST
RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW SPOT AND COVER YOUR
HEAD.

STAY TUNED TO WEATHER RADIO OR LOCAL MEDIA OUTLETS FOR THE LATEST
SEVERE WEATHER INFORMATION.
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Seriously! Why is there no tornado warning!?
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Quoting KEEPEROFTHEGATE:
this season is gonna be a close to home season with the CARB. GOM Bahama area being the main players this season


Yeah, probably.
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Quoting Ameister12:

When Friday comes, are you expecting a moderate risk, or what?

Based off the GFS, which seems to have the best handle on the situation, yes.
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NWS, why did you discontinue the warning? It's gaining its rotation back.

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Quoting TropicalAnalystwx13:
The GFS has trended much more aggressive with Friday's outbreak over the past few runs...expect a risk area by tomorrow, at which time it will probably be given a high-end Slight risk.

When Friday comes, are you expecting a moderate risk, or what?
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The concordia rotation is reintensifying but unfortunately, the spotter i was following can no longer keep up with the storm:


Also new rotation appears to be coming up in south Kansas:
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Quoting KoritheMan:


I'm still not that concerned with the Pacific. Though I agree that the anomalous cooling of the MDR could curb tropical cyclone potential, especially farther east toward west Africa, where the ongoing drought could limit Cape Verde hurricanes. On the other hand, such a setup would allow for tropical waves to develop farther west, giving them less prospect for recurvature into the westerlies.
this season is gonna be a close to home season with the CARB. GOM Bahama area being the main players this season
Member Since: July 15, 2006 Posts: 174 Comments: 54483
The GFS has trended much more aggressive with Friday's outbreak over the past few runs...expect a risk area by tomorrow, at which time it will probably be given a high-end Slight risk.
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Quoting WxGeekVA:
Wait... What in the heck is this on the GFS?!?!



that is some mighty warm air for that far north this time of year....what in the world?
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Tornado warning for Republic County has been canceled, but I still see some strong rotation. ???
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Quoting KoritheMan:


I'm still not that concerned with the Pacific. Though I agree that the anomalous cooling of the MDR could curb tropical cyclone potential, especially farther east toward west Africa, where the ongoing drought could limit Cape Verde hurricanes. On the other hand, such a setup would allow for tropical waves to develop farther west, giving them less prospect for recurvature into the westerlies.
*cough* *cough* 2005...
Member Since: August 14, 2010 Posts: 10 Comments: 17097
Quoting KEEPEROFTHEGATE:



I'm still not that concerned with the Pacific. Though I agree that the anomalous cooling of the MDR could curb tropical cyclone potential, especially farther east toward west Africa, where the ongoing drought could limit Cape Verde hurricanes. On the other hand, such a setup would allow for tropical waves to develop farther west, giving them less prospect for recurvature into the westerlies.
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Quoting GeorgiaStormz:


Possible Tornado


Does look like a possible - rain-wrapped?

Where is it?
Member Since: April 29, 2006 Posts: 154 Comments: 18769

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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.