La Nina

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NZstorm
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La Nina

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Latest from NOAA on La Nina
Nearly all models predict La Niña to continue through early 2011. However, there is disagreement among the models over the eventual strength of La Niña. Most dynamical models generally predict a moderate-to-strong La Niña, while the majority of the statistical model forecasts indicate a weaker episode. Given the strong cooling observed over the last several months and the apparent ocean-atmosphere coupling (positive feedback), the dynamical model outcome of a moderate-to-strong episode is favored at this time. Therefore, La Niña conditions are expected to strengthen and last through Northern Hemisphere Winter 2010-11.
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David
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Re: La Nina

Unread post by David »

Might mean a wetter summer for the north/east?
Although as far as I can recall last La Nina summer was bone dry...
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NZstorm
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Re: La Nina

Unread post by NZstorm »

A rainfall distribution chart for La Nina/El Nino from NIWA. Shows essentially normal to above normal rainfall in the east and north and below normal rainfall on the SI West Coast/Alps during La Nina.

I guess there could be implications for NZ's hydro power supply next year.
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Re: La Nina

Unread post by tgsnoopy »

NZstorm wrote:I guess there could be implications for NZ's hydro power supply next year.
Let's hope they manage it better this time if that pans out.
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Re: La Nina

Unread post by NZ Thunderstorm Soc »

Yes, sadly the La Nina, (I hope I got it right), looks to be way up there but with climate change, alot of the conditions of the scenarios, I think are changing, so actual predictions of what La Nina events, (I hope I got it right) ,could variate away from what the actual La Nina, (I hope I got it right), is expected to bring to our weather, during the La Nina ( I hope I got it right) period. :smile:

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Michael
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Re: La Nina

Unread post by Michael »

The low pressure patterns look elnino,dont know who can remember 1989 was like this but they came down from the north more so.
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Re: La Nina

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Yes, the last strong La Nina was 1988-89. There were weaker La Nina in 1998/99 and 2000/01. The summers of the late 1990's were the warmest on record I believe.
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Re: La Nina

Unread post by RWood »

The La Nina ONI values from 1988/89 (from NOAA/NCEP's "evolution" PDF) - the signs are the opposite to those for the SOI:

AMJ 1988 –AMJ 1989 -1.9
ASO 1995 –FMA 1996 -0.7
JJA 1998 –MJJ 2000 -1.6
SON 2000 –JFM 2001 -0.7
ASO 2007 –AMJ 2008 -1.4

The rainfall response is quite variable, as the 2007/8 case bears out.

In the NZ temperature series, the summer of 1998/99 was the 4th warmest (1934-35 was easily the warmest, followed by 1974-75 and 1937-38). 1997/98 was the 8th warmest - a relatively cool start in December stopped it ranking higher.
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Re: La Nina

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Rainfall can be a hit and miss thing too. If we can get an ex tropical low onto northern NZ this summer that can add 300 to 400mm to the seasonal total. Northern NZ is overdue for a decent hit from an ex-tropical cyclone so maybe this will be the summer for it.
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