La Nina could return

[Tornado Tim]

Been looking at the SOI and it seems like its trending back to the La-Nina pattern.

Hopefully this is only a short term trend otherwise our thunderstorm season is going to be pathetic like this years.

On the other hand Australia's NSW and Queensland Thunderstorm season expected to be fantastic.....

Please cross your fingers we go into El-Nino or stay ENSO-neutral at least.

[Manukau heads obs]

I think we will return to moderate La Nina myself ....
one good thing is less SW winds and generaly not as dry for the upper NI

[Michael]

Each el nino and la nina seems to be different,ie 82-83 was very westerly,88-89 NE and wet wheres the 97-98 one started cold but ended up more NW and the last la nina nowhere the amount of NE as expected.
If 77-78 was an el nino that was an anticyclonic one and the 96-97 one was a cooler la nina.

[Manukau heads obs]

there was lots of NE periods in the last La Nina
just not very long lasting episodes

[Nev]

Not too sure about John's "run-down of the El Nino weather pattern" comment?
[...on the other thread.]

Most models are now predicting a mild return to La Nina for the upcoming season. NIWA has also been quoted from their latest October to December Outlook as saying, 'La Nina conditions are redeveloping in the tropical Pacific, and the event is expected to build through spring and continue over the summer season'.

[Manukau heads obs]

he might have got them confused again?

[Michael]

Maybe John means what hes saying,its running down ie dimutative after trying to begin commencing.

[NZ Thunderstorm Soc]

Not too sure about John's "run-down of the El Nino weather pattern" comment?

Sorry, Nev. I always get the 2 names confused
A return to a full LA NINA looks likely later as you said



JohnGaul
NZThS

[Nev]

LOL . I wouldn't say 'full La Nina', but most ENSO indicators have remained positive throughout the S'ern winter. SOI values have fluctuated a bit, but the latest 30-day SOI values are now at +9.3 ...

BoM - ENSO Wrap-Up
Issued on Wednesday 28 September 2011

Odds firm for a La Niña in 2011

The continuing cooling trend in the central Pacific Ocean since early winter is consistent with a developing La Niña event. For example, temperatures below the surface of the tropical Pacific Ocean during September are 4 °C cooler than average in some areas. The majority of leading climate models predict current patterns and trends will continue, with further cooling beyond La Niña thresholds during the last quarter of 2011.

Atmospheric indicators are also trending towards typical La Niña values. Trade winds have been persistently stronger than normal in the central and western Pacific Ocean, and the Southern Oscillation Index (SOI) this week reached the threshold value of +8. Sustained values at this level are an indication of La Niña.

If a La Niña does form, current indicators are that it will be weaker than the strong 2010-11 event. ...

(full report)

Thought today's La Nina comments might be better suited to this thread. Also changed link.

[Manukau heads obs]

good info here
http://www.weatherzone.com.au/climate/i ... .jsp?c=soi
and
http://www.weatherzone.com.au/climate/i ... p?c=nino34
(note, John,that 2nd one is sort of opposite on the graph )

[NZ Thunderstorm Soc]

good info here
http://www.weatherzone.com.au/climate/i ... p?c=nino34
(note, John,that 2nd one is sort of opposite on the graph )

Yeah, I see what you mean
No, it's just me getting senile

JohnGaul
NZThS