ENSO Discussion - Part II

[Mike S]

I was reminded of this thread on the old board while reading a report this morning and thought it would be a good idea to relaunch the discussion.

Yesterday, the CPC released a discussion basically putting us under a La Nina Watch for the coming Winter season.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf

 

[Jacob]

It has been impressive how badly all of the seasonal models have busted on the upcoming winter idea for El Nino/La Nina. Back in the spring most model plumes had a moderate El Nino developing, now many are trending towards a moderate La Nina.

 

[Kory]

It's been a while since I logged in (busy with grad school stuff), but I saw this topic and couldn't help since it might be my favorite meteorological/climate phenomena. Impressive trades continue along and west of the dateline and we have a much better atmospheric coupling than last year (which yielded a weak Nina).

The AAM (or atmospheric angular momentum) can give an idea of the atmospheric state. It is largely negative and is forecasted to continue. The latest ENSO forecasts continue this downward trend in response to the continued/strengthening Nina atmospheric/ocean coupling. Some models even get it as strong as borderline mod/strong Nina.

So what does this all mean? Well, it will be strongly reflected in the pattern ahead. Ensembles continue to drop troughing into the NW with general ridging over the Central/Eastern part of the country (for the next 2/3 weeks). And likely an active Atlantic continues....this hurricane season is a lot more active thanks in part to the developing Nina of note. I still think we have 3/4 weeks left...and the Nina pattern ahead points to continued U.S. threats...

 

[tennessee storm chaser]

It's been a while since I logged in (busy with grad school stuff), but I saw this topic and couldn't help since it might be my favorite meteorological/climate phenomena. Impressive trades continue along and west of the dateline and we have a much better atmospheric coupling than last year (which yielded a weak Nina).

The AAM (or atmospheric angular momentum) can give an idea of the atmospheric state. It is largely negative and is forecasted to continue. The latest ENSO forecasts continue this downward trend in response to the continued/strengthening Nina atmospheric/ocean coupling. Some models even get it as strong as borderline mod/strong Nina.

So what does this all mean? Well, it will be strongly reflected in the pattern ahead. Ensembles continue to drop troughing into the NW with general ridging over the Central/Eastern part of the country (for the next 2/3 weeks). And likely an active Atlantic continues....this hurricane season is a lot more active thanks in part to the developing Nina of note. I still think we have 3/4 weeks left...and the Nina pattern ahead points to continued U.S. threats...

kory... also starting to get very concerned with severe weather outbreaks later this fall into winter even for the south... this nina means business

 

[Kory]

La Nina has been officially declared. Looking at the SSTA maps, it certainly is taking off and appears to be east based so far. Subsurface is showing a strong upwelling wave that should push this event more toward moderate, especially with the next trade surge east of the dateline.

 

[Kory]

Second week of moderate La Niña readings. 3.4 came in at -1.1C last week and held serve this week. Niño 3.4 saw the biggest drop since keeping weekly records last week.

Enhanced trades continue as this La Niña ramps up.

 

[Kory]

What a trade wind enhancement coming!

 

[Mike S]

The June ENSO forecast estimates a 50% chance of El Niño developing during the late summer or early autumn, and an approximately 65% chance of El Niño conditions in the winter, so forecasters have instituted an El Niño Watch.

https://www.climate.gov/news-features/blogs/enso/june-2018-enso-update-el-niño-watch