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BoM: 70%+ chance of El Nino developing
Posted: Tue 08/04/2014 20:57
by Willoughby
Sorry couldn't find any word from NIWA.
El Niño likely to develop in winter
Issued on Tuesday 8 April 2014 | Product Code IDCKGEWWOO
It is now likely (estimated at a greater than 70% chance) that an El Niño will develop during the southern hemisphere winter. Although the El Niño–Southern Oscillation (ENSO) is currently neutral, surface and sub-surface ocean temperatures have warmed considerably in recent weeks, consistent with a state of rapid transition. International climate models surveyed by the Bureau indicate continued warming of the central Pacific Ocean in coming months. Most models predict sea surface temperatures will reach El Niño thresholds during the coming winter season.
El Niño is often, but not always, associated with below normal rainfall across large parts of southern and inland eastern Australia during the second half of the year. The strength of an El Niño does not always indicate how much it will influence Australian rainfall. Historically there are examples where weak events have resulted in widespread drought across large parts of Australia, while at other times strong events have resulted in relatively modest impacts. It is too early to determine the strength of this potential El Niño. Daytime temperatures tend to be above normal over southern Australia during El Niño.
The Indian Ocean Dipole (IOD) is currently in a neutral state. Model outlooks indicate the IOD will remain neutral through late autumn and early winter. The chance of a positive IOD event occurring will increase if an El Niño develops.
http://www.bom.gov.au/climate/enso/#tabs=Overview
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 16:47
by Tornado Tim
Potentially good news for NZ
Hopefully it will deliver the rain and stick around next summer.
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 18:13
by jamie
El Nino's can deliver incredible drought to NZ. Not sure its good news, but then again we can get anything in any weather pattern
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 18:27
by David
Like Jamie said, for much of the country I think that El Nino tends to result in drier weather in summer (apart from South Island West Coast). Having said that, I would be surprised if we had another drought again next summer!
EDITED to correct La Nina to El Nino - oops!
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 19:00
by spwill
A wet Spring on the way in the west, drier than average in the east. A dry summer on the cards for the north and east of the country but not necessarily warmer.
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 19:33
by NZstorm
The risk of summer drought over the North Island is quite high with El Nino and the drought will be severe in the east.
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 19:39
by Storm Struck
Correct me if I am wrong but I thought El Nino meant more southerlies in the east drier out west?
BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 20:09
by jamie
Isn't El Niño SW. So wet in the west and dry in the east. La Niña is NE. Or have I got that wrong?
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 20:37
by Manukau heads obs
West means west coast of SI
More rain there in an el Nino
Droughts for eastern both islands
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 20:51
by Tornado Tim
We certainly have not done well with a La Nina, thats for sure....
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 20:54
by spwill
Storm Struck wrote:Correct me if I am wrong but I thought El Nino meant more southerlies in the east drier out west?
Might be the case in Winter, atleast more in the way of cold flows onto the country
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 09/04/2014 20:57
by David
jamie wrote:Isn't El Niño SW. So wet in the west and dry in the east. La Niña is NE. Or have I got that wrong?
Usually it will only be wet in the west of the South Island. In summer the westerly fronts tend to fizzle once they reach the North Island, as far as I can remember.
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 06:18
by matttbs
What will this mean for the coming winter? Will it be warmer with rain or can we expect more cold snowy conditions?
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 06:52
by Manukau heads obs
Basicly every el nino will be different
So you Can only talk about trends
The 1993 el nino was Aucklands driest
Year on record
But a mild winter...just lots of relatively weak fronts
From the tasman that year and lots of highs full of anticyclonic gloom
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 08:55
by spwill
Yes, we are just guessing however dry does seem to be a feature with El Nino years
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 09:49
by Razor
Storm Struck wrote:Correct me if I am wrong but I thought El Nino meant more southerlies in the east drier out west?
Completely agree with the others above. My understanding is that El Nino freshens the westerly quarter systems, which means drier for the east, wetter for the West Coast. More SW than southerlies behind the fronts which means less moisture in Canterbury, etc
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 20:07
by RWood
1987 winter was westerly and exceptionally mild - very dull in some western districts. West Coast rainfall has varied a lot in El Nino events - not a lot in the 1991-2 period, huge amounts in 1997-1998 (over 18,400mm at Cropp Waterfall in one 365-day period), which carried on into the start of a La Nina. Milford had record high rainfall in 1988 which also saw a transition to a la Nina
Re: BoM: 70%+ chance of El Nino developing
Posted: Thu 10/04/2014 20:18
by Bradley
El Nino generally means drier for the east with more westerlies but it also means colder temps for the south island in winter and more of a SW flow...
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 09:41
by Skywatcher
NASA article on the similarities between 2014 and 1997 for El Nino development:
http://science.nasa.gov/science-news/sc ... ay_elnino/
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 11:40
by Manukau heads obs
1997 was a clayton's el nino for NZ though
from what I remember
i.e an el nino when you re not having an el nino
olders members will know what clayton refers too
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 12:09
by RWood
Manukau heads obs wrote:1997 was a clayton's el nino for NZ though
from what I remember
i.e an el nino when you re not having an el nino
olders members will know what clayton refers too
No - while it was a warm one, there were huge rainfall contrasts, including the record values as above.fh
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 12:14
by SnwAddct
Excuse my ignorance but going by trends, El Nino generally means less or more snow fall?
BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 15:48
by jamie
Wasn't it the 1998/9 El Niño that gave big dry conditions across the country. I'm assuming that El Niño was a continuation of the 97 one
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 19:10
by RWood
jamie wrote:Wasn't it the 1998/9 El Niño that gave big dry conditions across the country. I'm assuming that El Niño was a continuation of the 97 one
That was a La Nina. The dryness in some western areas started about Nov 1999, straight after exceptional wetness in many western parts from Fiordland to Taranaki (Oct 1998 mainly).
Re: BoM: 70%+ chance of El Nino developing
Posted: Wed 21/05/2014 19:43
by Nev
Yes, 1998/99 was a La Nina summer here, as was the summer of 1996/97.
The article posted by Skywatcher above compares current similarities to the lead-up of the big El Nino of 1997/98, which saw summer droughts in eastern parts of NZ. However, although it was also a very warm summer for NZ, this is not typical of our El Nino summers.