ENSO Updates (2007 thru 2023)

[Mathias]

Wasn't 2005 a neutral year?

[windstorm99]

2005 was indeed a neutral year and infact neutral years have had more landfalling tropical systems in florida then la nina.

Tracks of Landfalling Hurricanes

[benny]

Not so sure about that... neutral years have proven to have more named storms than La Nina years

Maybe recently.. but not over the long haul. Your best bet for more hurricane activity is still a La Nina...

[SouthFloridawx]

Not so sure about that... neutral years have proven to have more named storms than La Nina years

Maybe recently.. but not over the long haul. Your best bet for more hurricane activity is still a La Nina...

Actually and I'll check on this but, I think there are more storms average in a la nina than neutral. There have been many more years of neutral than la nina, so it's hard to compare.

[windstorm99]

I think if we have a nina or neutral conditions really does not matter that much as i think were going to see an above average season.The big question is were are they going to track this season which in all honesty is something that really cannot be forcasted.I tend not focus on numbers anyway as even a quite season can turn out catastrophic .

[AussieMark]

neutral years typically have more storms but La Nina years have more Hurricanes and Majors

[P.K.]

The three month Nino 3.4 anomaly mean rose this week for the second week in a row and now stands at +0.09C. The BoM update issued on 13/6/2007 is posted below.

CURRENT STATUS as at 13th June 2007
Next update expected by 27th June 2007 (two weeks after this update).
| Summary | In Brief | Details |

Summary: La Niña development stalls

Although computer models show a La Niña event is likely in 2007, there has been little further development during the past month. Current conditions in the equatorial Pacific remain neutral.

The precursors for the development of a La Niña event are still evident. The most important is the presence of cooler than normal conditions in the Pacific Ocean subsurface - a situation that has persisted since mid-January - which have led to cooler than average surface waters in the eastern Pacific, despite some warming during the past fortnight. In addition, subsurface waters are much warmer than in April or May, although they're still cooler than average. This recent warming trend in ocean temperatures appears to have, at least temporarily, stalled the development of a La Niña event.

There is no apparent trend as yet in the amount of convection (high cloud) near the date-line, but the 30-day average SOI has risen to small positive values. Furthermore, the Trade Winds have become close-to or stronger than average in the western to central Pacific. A switch to consistently reduced convection, stronger positive SOI values and stronger than average Trade Winds would be favourable indications for La Niña development.

The fact that all major international coupled models show further cooling of the equatorial Pacific Ocean over the coming months, suggests that there is an elevated chance of a La Niña event occurring in 2007. Conversely, this suggests that the El Niño risk is very low. Historically, La Niña events bring wetter than normal conditions across much of the eastern half of Australia during the second half of the year. Furthermore, the years following El Niño usually bring average to above average rainfall to eastern and southern Australia.

[Coredesat]

That seems to support the "no La Nina" statement I made a while back. The subsurface anomalies west of 160W have been warming, and the cold anomalies haven't made any movement.

[P.K.]

All Nino regions rose to the week ending 17/6/2007 in terms of the weekly SSTA. I'll see how this affects the three month running mean later.

[cycloneye]

Climate Prediction Center 6/18/07 Update,pdf form



A change in their message,now saying that Neutral ENSO will dominate for the next 3 months.In past updates they have been saying that La Nina would be in the Pacific in the next 1-3 months.

P.K.,you posted earlier something important about the temps that now CPC confirms.This is big news.

[windstorm99]

Wow this is pretty significant news!

[P.K.]

P.K.,you posted earlier something important about the temps that now CPC confirms.This is big news.

I've been saying this for a while now. By the way the Nino 3.4 three month mean hasn't fallen for four weeks now and has risen the past 3 weeks. The subsurface charts have also warmed somewhat in the last month.

Here is a copy of my weekly update that I don't usually post here. The figure in brackets is the three month running mean.

Week ending 17/6/2007:

Nino 1: -0.61C
Nino 2: -0.21C
Nino 3: -0.14C (-0.17C)
Nino 3.4: +0.16C (+0.09C) - The three month mean has risen for the third week in a row.
Nino 4: +0.41C (+0.31C)

[cycloneye]

In other words,what the CPC update told us is that La Nina is

Note:Link is not working at the moment.Aparently there are many hits to that site after the news came out that is causing it to be down.The link is posted three posts above this one.

[Taxman]

If you go to the Climate Prediction Center site and click on the weekly update, the link now takes you to the June 11th weekly update.

[cycloneye]

This is the link that they have where they issue their updates.

http://www.cpc.ncep.noaa.gov/products/a ... _advisory/

If you have another link for the CPC updates you can post it.

[windstorm99]

Here is an interesting study done by hurricanalley a few months back indicateing that most active years were those that were neutral with a bias towards La Nina through the season similar to like 05.

Hurricane alley 07 atlantic study

[Taxman]

Here is the link from CPC

http://www.cpc.noaa.gov/products/analysis_monitoring/enso_advisory/

[deltadog03]

Once again the CFS is REALLY struggling with this!

[MiamiensisWx]

Despite a strong -PDO signal, we have not observed a westward expansion of the coolest anomalies (at the surface or subsurface). The strongly positive SOI may enhance sfc easterlies, but the overall Pacific trend resembles 2004. A cool subsurface develops within the eastern NINO zones by April; it initially intensifies, but it eventually collapses and a Nina never materializes (despite a -PDO signal). Kelvin Waves halt the development of a cool phase (ENSO). The warm anomalies have expanded eastward, and the persistent cool anomalies have been shrinking within recent weeks.

The Kelvin Waves have been easily propagating eastward across the South Pacific. This has been mitigating the formation of a Nina. This is quite evident at the subsurface. The SSTs have been responding to the effects. In addition, the stronghold of the coldest anomalies (NINO 1 and 2) is weakening. The trend is visible at the surface and subsurface. I strongly believe that we may not see a La Nina in 2007. Let's observe the progression of these Kelvin Waves.

[cycloneye]

Here is the link from CPC

http://www.cpc.noaa.gov/products/analysis_monitoring/enso_advisory/

Hmmm,it's weird that in that link the 18th of June weekly update is not there but the 11th is.I am not crazy as I saw the 18th and rapidly posted it as it's big news.

Anyway,I agree with MiamiensisWx that La Nina wont be around for the rest of 2007.