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Models seem to have been strengthening the Nina forecast and it'sprobably not hard to see why (also why i suspect our summer is going to deteriorate after it's current last stand).

SubSurfTemp_2016Mar14-May3_620.gif

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Rapid change to La Nina seems to be afoot.  End of Feb

http://www.ospo.noaa.gov/data/sst/anomaly/2016/anomnight.2.29.2016.gif

 

To now

 

http://www.ospo.noaa.gov/data/sst/anomaly/2016/anomnight.5.23.2016.gif

 

La Nina comes knocking

 

BFTP

 

 

Edited by BLAST FROM THE PAST
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Both 1.2 and 3.4 are down to 0.2 and Nino 3 is actually now negative.

Nino is all but dead.

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Funnily enough, the most similar years to 2016 when assuming a La Nina by the summer don't indicate much at all for Jul-Aug temperatures. Alas, I'm not allowed to tell you the exact numbers as it's for professional interests. Precipitation is more interesting and agrees with a deterioration in some parts of the UK - but I can't tell you where!

You do get the generally better start to the season being indicated, though.

 

Edited by Singularity
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The tropical Pacific Ocean has returned to a neutral El Niño–Southern Oscillation (ENSO) state. Sea surface temperatures across the tropical Pacific have cooled to neutral levels over the past fortnight, supported by much cooler-than-average waters beneath the surface. In the atmosphere, indicators such as the trade winds, cloudiness near the Date Line, and the Southern Oscillation Index have also returned to neutral levels. Outlooks suggest little chance of returning to El Niño levels, in which case mid-May will mark the end of the 2015–16 El Niño.  

International climate models indicate the tropical Pacific Ocean will continue to cool, with six of eight models suggesting La Niña is likely to form during the austral winter (June–August). However, individual model outlooks show a large spread between neutral and La Niña scenarios.

Changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks, suggest the likelihood of La Niña forming later in 2016 is around 50%, meaning the Bureau's ENSO Outlook remains at La Niña WATCH.

Typically during La Niña, winter-spring rainfall is above average over northern, central and eastern Australia.

Climate model outlooks for the Indian Ocean Dipole (IOD) suggest a negative IOD event is likely to develop during the austral winter. However, outlook accuracy for the IOD at this time of year is low. A negative IOD typically brings increased winter-spring rainfall to southern Australia.

http://www.bom.gov.au/climate/enso/index.shtml

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3 hours ago, Singularity said:

Funnily enough, the most similar years to 2016 when assuming a La Nina by the summer don't indicate much at all for Jul-Aug temperatures. Alas, I'm not allowed to tell you the exact numbers as it's for professional interests. Precipitation is more interesting and agrees with a deterioration in some parts of the UK - but I can't tell you where!

You do get the generally better start to the season being indicated, though.

 

I believe it's been suggested that no month has an especially strong correlation with the cet to Nina/Nino however the typical response (and one we observed several times in the last decade) is that when GLAMM falls through the floor, the UK summer waves goodbye. 

The next set of easterly trades will be telling in terms of how strong the atmospheric response starts to be i imagine.

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2 hours ago, knocker said:

The tropical Pacific Ocean has returned to a neutral El Niño–Southern Oscillation (ENSO) state. Sea surface temperatures across the tropical Pacific have cooled to neutral levels over the past fortnight, supported by much cooler-than-average waters beneath the surface. In the atmosphere, indicators such as the trade winds, cloudiness near the Date Line, and the Southern Oscillation Index have also returned to neutral levels. Outlooks suggest little chance of returning to El Niño levels, in which case mid-May will mark the end of the 2015–16 El Niño.  

International climate models indicate the tropical Pacific Ocean will continue to cool, with six of eight models suggesting La Niña is likely to form during the austral winter (June–August). However, individual model outlooks show a large spread between neutral and La Niña scenarios.

Changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks, suggest the likelihood of La Niña forming later in 2016 is around 50%, meaning the Bureau's ENSO Outlook remains at La Niña WATCH.

Typically during La Niña, winter-spring rainfall is above average over northern, central and eastern Australia.

Climate model outlooks for the Indian Ocean Dipole (IOD) suggest a negative IOD event is likely to develop during the austral winter. However, outlook accuracy for the IOD at this time of year is low. A negative IOD typically brings increased winter-spring rainfall to southern Australia.

http://www.bom.gov.au/climate/enso/index.shtml

Regarding the IOD i have to agree. The sea surface temperature anomalies are pretty classic and well advanced compared to the main ENSO region. 

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16 minutes ago, summer blizzard said:

Regarding the IOD i have to agree. The sea surface temperature anomalies are pretty classic and well advanced compared to the main ENSO region. 

I must admit given the current Nina forecasts I'm struggling to understand why it should any major affects on our summer.

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1 hour ago, knocker said:

I must admit given the current Nina forecasts I'm struggling to understand why it should any major affects on our summer.

I'm not aware of the IOD having any strong correlation (and indeed i don't think ENSO and the CET are especially correlated). I think the assumption is that as Nina gets stronger angular momentum will fall and that this low angular momentum pattern was commomplace in some of the summers in the 07-12 period. 

Of course it's all speculation at this stage and my own belief is simply that any sustained warmth is more likely early than late.

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Anybody know what effect a stronger Walker cell has on UK weather?

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20 hours ago, summer blizzard said:

I believe it's been suggested that no month has an especially strong correlation with the cet to Nina/Nino however the typical response (and one we observed several times in the last decade) is that when GLAMM falls through the floor, the UK summer waves goodbye. 

The next set of easterly trades will be telling in terms of how strong the atmospheric response starts to be i imagine.

Yes, that's the best way of looking at it that I know of, as opposed to the month-mean temperatures. I expect much of the uncertainty in seasonal models for this summer is related to how soon GLAAM tanks in response to the changing Pacific SSTs and convection pattern (Walker Cell).

Generally, it seems the effects of La Nina on the UK's weather are less well investigated that that of El Ninos - quite possibly because La Nina is like an enhanced version of the usual convective pattern, while El Nino is a drastic weakening or reverse. Yet La Nina still causes anomalous weather for many parts of the globe so there's obviously a significant effect on momentum transport.

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On 25 May 2016 at 17:27, Singularity said:

Funnily enough, the most similar years to 2016 when assuming a La Nina by the summer don't indicate much at all for Jul-Aug temperatures. Alas, I'm not allowed to tell you the exact numbers as it's for professional interests. Precipitation is more interesting and agrees with a deterioration in some parts of the UK - but I can't tell you where!

You do get the generally better start to the season being indicated, though.

 

How tantalizing - please tell us when nearer to the time what you meant , I will try and guess in the mean time.

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On 6/1/2016 at 11:48, Woollymummy said:

How tantalizing - please tell us when nearer to the time what you meant , I will try and guess in the mean time.

The mix of results is down to how the global atmospheric angular momentum (GLAAM behaves). For info on that, see Tamara's excellent post in the MOD thread today:

 

It's in the balance!

Edited by Singularity
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On 6/6/2016 at 21:11, summer blizzard said:

cdas-sflux_ssta_relative_global_1.png

Interesting how that is set against the global mean SSTA at that timeframe. A normalised plot that lets you see the components to the mean very clearly. A nice find! :good:

A traditional anomaly plot against the LTA shows a configuration that is less clearly in a La Nina state:

sst.daily.anom.gif

The pattern of 'hot blobs' is striking. Just what is the mechanism behind such a thing?

Elsewhere it's worth noting the fascinating contrasts in the N. Pacific at the moment, and that band of remarkably warmer than usual waters extending from just NW of Africa to Iceland. An artifact of recent weather patterns that may have implications on late June and early-mid July provided other forcing variables don't act in opposition (see the MOD thread for my discussion on that).

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Nino 3.4 region has rebounded back up into El Nino territory and the subsurface cold pool is rapidly weakening. Who'd have guessed that!?

nino34.png 2bhQRUZ.png

 

yOfqobM.png

 

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Strange to see how much 1.2 has jumped around although its interesting that 3.4 rose too. 

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7 minutes ago, knocker said:

 

Bit of a turn up this, but I won't moan as i'd much prefer to head into winter with a -QBO/ENSO neutral combo than with a raging strong Nina

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It appears the spring barrier of forecasting has once again proven it's not wise to make calls until we've reached Summer. Does anyone have any past strong Nino to Niña charts which compare  to the present, I know 98 went from a record Nino to a very strong Niña  but I can't find anything similar to what's showing now?

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1 hour ago, Hocus Pocus said:

It appears the spring barrier of forecasting has once again proven it's not wise to make calls until we've reached Summer. Does anyone have any past strong Nino to Niña charts which compare  to the present, I know 98 went from a record Nino to a very strong Niña  but I can't find anything similar to what's showing now?

98-99 had a very short neutral period in the Spring (around a month) before the Nina came steamrolling in May of 98 and continued into 1999.

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