ENSO Updates (2007 thru 2023)

[cycloneye]

Dr Jeff Masters made a very good blog about the present strong MJO and the implications going forward on ENSO.

The Madden Julian Oscillation (MJO) is a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days, and has many important impacts on weather patterns world-wide. For example, when the area of increased thunderstorms associated with the MJO is located in a particular ocean basin, the odds of tropical cyclone formation increase there. Scientists use the Wheeler-Hendon MJO index to monitor how strong the MJO is, and this week, the amplitude of the MJO set a new all-time record for the strongest MJO event observed since record keeping began in 1974 (with no data available from 3/17/1978-12/31/1978 due to satellite problems). The MJO index hit 4.09 on March 15, 2015, beating the old record of 4.01 set on February 14, 1985. On March 16, 2015, the MJO index set an even higher mark--4.67. That was likely the peak of this record MJO event, as the MJO index fell to 4.51 on March 17, and is forecast to drop significantly over the coming week. Thanks go to CSU's Phil Klotzbach for alerting me to the MJO record.


Figure 1. Wind flow diagram from March 13, 2015, when counter-rotating tropical cyclones on each side of the Equator in the Pacific created strong westerly winds along the Equator. Image credit: http://earth.nullschool.net/.

This record-strength MJO event began increasing in intensity last week, and aided in the formation of twin tropical cyclones, one on each side of the Equator (an event that tends to happen at least once per year.) The Southern Hemisphere storm that formed was Tropical Cyclone Pam, which intensified to Category 5 strength and devastated the island nation of Vanuatu. The Northern Hemisphere tropical cyclone, Tropical Storm Bavi, was not as strong since it had cooler waters to navigate, but still managed to attain peak winds of 60 mph before decaying to a tropical depression this Wednesday. These two tropical cyclones were counter-rotating--the Northern Hemisphere storm spun counter-clockwise, while the Southern Hemisphere storm spun clockwise. As a result of having two counter-rotating storms on either side of the Equator, very strong west-to-east blowing winds formed along the Equator, opposing the usual east-to-west blowing equatorial trade winds. The westerly winds from the counter-rotating tropical cyclones were strong enough and persistent enough that they boosted the odds of the current weak El Niño event staying on through the summer and into fall, since these "westerly wind bursts" tend to move warm water from the Western Pacific into the Eastern Pacific (the presence of warmer-than-average water in the Eastern Pacific is needed for an El Niño event to occur.) According to an email I received from University at Albany El Niño expert Paul Roundy, he expects an 80% chance that there will be a strong El Niño late this year, based on the latest model forecasts, and the evolution of the present event--which is being boosted by the current record-strong MJO, and was helped along by the counter-rotating tropical cyclones in the Pacific last week. He cautions, though, that "failure of El Niño could occur this year if sufficient warm water volume is expelled up and down the coasts of the Americas before June, without maintenance of westerly wind burst activity into June (when the equatorial easterly winds typically amplify with the seasonal cycle and bring the cold tongue back.) "


Figure 2. Projections of sea-surface temperature in the Niño 3.4 region (5°S - 5°N, 120°W - 170°W), where SSTs must be at least 0.5°C above average for five consecutive months (each month being a 3-month average) for an El Niño event to be declared. These forecasts are for August 2015 in terms of departure from average (degrees C), as compiled from eight international climate models and released by the Australian Bureau of Meteorology in a March 17 update. Each model’s projection on the graph above is based on the average of multiple runs in an ensemble. The threshold for El Niño conditions for Australia is 0.8°C above average, as shown on the chart, while the NOAA threshold (not shown) is 0.5°C. Image credit: National Climatic Data Center (NCDC) .

In a March 17 outlook, Australia's Bureau of Meteorology bumped up their El Nino odds. They stated, "The past fortnight has seen unusual conditions in the tropical Pacific, which may increase the chance of El Niño in 2015. In the western Pacific, severe Tropical Cyclone Pam and Tropical Storm Bavi straddled the equator, producing one of the strongest reversals in the trade winds in recent years. This change is expected to increase the already warm sub-surface temperatures currently observed in the tropical Pacific Ocean, which may in turn raise tropical Pacific Ocean surface temperatures in the coming months. All eight international models surveyed by the Australian Bureau of Meteorology project that water temperatures will increase by August to at least 1.0°C above average in the Niño 3.4 region (see Figure 2), which would suggest at least a moderately strong El Niño event by NOAA’s definition.

NOAA's Climate Prediction Center is saying that there is an approximately 50-60% chance that El Niño conditions will continue through Northern Hemisphere summer 2015. This outlook was issued before the recent record-strength MJO and counter-rotating Pacific tropical cyclones emerged, so it will interesting to see how their outlook changes in the next update on April 9.

If El Niño is present this fall, it increases the odds that we will have a quiet Atlantic hurricane season. El Niño typically brings high wind shear to the tropical Atlantic, disrupting hurricanes and tropical storms as they try to form or intensify. Conversely, El Niño favors a more active than usual Eastern Pacific hurricane season, by lowering wind shear there and increasing water temperatures. If we get a strong El Niño this winter, it would increase the odds of breaking California's streak of four consecutive dry winters, and put a decent dent in their crippling drought. As we saw this past winter, California can still get low precipitation and drought conditions during a weak El Niño event. If El Niño builds and stays through the summer, warmer waters in the Pacific could lead to a wide-scale coral bleaching event, resulting in massive die-off of coral.

Jeff Masters

[HURRICANELONNY]

Another dead hurricane season! Oh well. I'll take it. But it only takes 1.

[Ntxw]

Nino 1-2 is warming rapidly with the surfacing pool. Just a testament of how quickly this region can change compared to the others.

[xtyphooncyclonex]

Wow, some 2C's already surfacing!

[Hurricaneman]

seems as though with the way things are going we may get a strong El Nino out of this and maybe the super El Nino that was expected last year this year

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[cycloneye]

Mid-March plume of models average for ASO is for moderate El Nino by those months.



http://iri.columbia.edu/our-expertise/c ... o/current/

[cycloneye]

MJO has gone nuts. Highest deviation from normal ever (single real time). SOI is crashing with it.

Surely yes.

SOI values for 20 Mar 2015



Average for last 30 days

-7.6



Average for last 90 days

-7.6



Daily contribution to SOI calculation

-31.2

[xtyphooncyclonex]

Wow from IRI (models average)


MJJ JJA JAS ASO SON OND

1 1.1 1.2 1.1 1.1 1

[Ntxw]

The strong WWB is coming to an end, there are still weak westerlies still expected and weaker trades (anomaly) but the damage has already been done. The warm pool will keep the Nino going at least through April and May. Nino 1+2 will probably experience the most rapid rise the next 30 days given how easy it is to warm as the warm pool begins to work it's way eastward.

On the other side there is an Atlantic "Nina" expected or the cold AMO-ish SST configuration (we saw some of it last year as well). This is the ring of cold waters in the eastern Atantic usually promoting +NAO. Raw values aren't quite -AMO but the layout resembles one.

[cycloneye]

Eric Blake@EricBlake12 · 1 hr1 hour ago

El Nino is still way ahead of this time in 2014-- stronger westerly wind forcing this year too.

Michael Ventrice@MJVentrice · 1 hr1 hour ago

This Summer's projected sea-surface temp anomaly map. Big Pacific El Nino signal and an "Atlantic Nina" response.

[Yellow Evan]

The strong WWB is coming to an end, there are still weak westerlies still expected and weaker trades (anomaly) but the damage has already been done. The warm pool will keep the Nino going at least through April and May. Nino 1+2 will probably experience the most rapid rise the next 30 days given how easy it is to warm as the warm pool begins to work it's way eastward.

On the other side there is an Atlantic "Nina" expected or the cold AMO-ish SST configuration (we saw some of it last year as well). This is the ring of cold waters in the eastern Atantic usually promoting +NAO. Raw values aren't quite -AMO but the layout resembles one.

With an expect SPAC monster in a bout a week, maybe this could spark a new WWB?

[Ntxw]

The strong WWB is coming to an end, there are still weak westerlies still expected and weaker trades (anomaly) but the damage has already been done. The warm pool will keep the Nino going at least through April and May. Nino 1+2 will probably experience the most rapid rise the next 30 days given how easy it is to warm as the warm pool begins to work it's way eastward.

On the other side there is an Atlantic "Nina" expected or the cold AMO-ish SST configuration (we saw some of it last year as well). This is the ring of cold waters in the eastern Atantic usually promoting +NAO. Raw values aren't quite -AMO but the layout resembles one.

With an expect SPAC monster in a bout a week, maybe this could spark a new WWB?

I'm not sure I trust a monster yet. If it does occur it won't be because of a large scale wind event like WWB as was with the recent event, more local favorability. The MJO will pass through quickly the IO region which may spark another real WWB but that won't be for another 20+ days. However weak westerlies will continue near the dateline.

[cycloneye]

Interesting articule about a possible double el nino.


We’re about to experience a “double El Niño” — a rare weather phenomenon that climatologists had warned about several months ago.

That means two consecutive years of the concentration of warm water in the Pacific Ocean that brings West Coast storms, quiet hurricane seasons in the Atlantic and busy ones in the Pacific. The danger is that this could mean more than a few months of odd weather, but instead usher in a new phase of climate change. Last year was the warmest year on record; 2015 looks set to be even warmer.


http://www.pri.org/stories/2015-03-22/w ... me-weather

[cycloneye]

It looks like Nino 3.4 will rise to +0.6C in the weekly CPC update of 3/23/15.Text coming in a few hours.

[cycloneye]

It looks like Nino 3.4 will rise to +0.6C in the weekly CPC update of 3/23/15.Text coming in a few hours.

The Text of CPC weekly update of 3/23/15.

http://www.cpc.noaa.gov/products/analys ... ts-web.pdf

[Ntxw]

1+2 continues to warm rapidly. No WWB but weaker trades will continue the warming trend or hold steady on this Nino. We finally got the Nino by the 5th year (never gone 5 years without one back to 1950) looks like we're going to do the rare double dip.

[cycloneye]

The Eurosip ensembles are at moderate close to strong El Nino by July-August.

[xtyphooncyclonex]

Feeling the drought now, unlike last year.

[cycloneye]

This was posted at WU by a knowleageble person about the MJO.

The global models (except for the american based guidance w/ Western Pacific initialization) have a well known tendency to move the MJO into the COD w/ increasing leads & they struggle immensely (even more so than the GFS w/ Western hemisphere MJO events) @ handling MJO initiation (via CCKW excitation w/ origins from the S America Amazon) over the Indian Ocean (phase 2-3). Granted, we didn't observe quite as dramatic of a flip this time as I'm accustomed to seeing, likely because we already had an exceptionally high amplitude MJO event in progress.

Unlike March 1997, this MJO pulse will continue to progress deep into the eastern hemisphere, potentially resulting in (or kickstarting) a well-adveristed period of interference that could intensify as we approach the climatological peak of the Southern Asia/Indian monsoons. 1997 decayed rapidly over the western IO, & failed to reach phase 3 w/ amplitude...

[cycloneye]

Dr Steve Gregory posted this at WU about El Nino getting stronger with time.

http://www.wunderground.com/blog/SteveG ... commenttop

Bunch of west winds warming waters.