NZ Weather Forum

The BoM have just initiated a La Nina watch. North American agency models are getting quite excited.

https://twitter.com/WeatherWatchNZ/stat ... 9099253767


weatherwatch thinks if we get a strong one we may be in for a wet summer?

Probably will.

Looks as though the Southern Oscillation Index will drive the 90 day average into positive territory shortly... right now Darwin 1013 hPa, Tahiti 1015 hPa with anomalous low pressure over Indonesia, Australia and continued blocking highs west of South America. Suggesting that the Walker circulation is starting to strengthen.

La Niña watch issued by the BOM today, they are rating it as having a 70% chance of developing this year:
http://www.bom.gov.au/climate/enso/index.shtml

Warm and drier in Southland if the La Nina develops

Even the North Island had a drought during a La Nina. (2007-08 to be exact).

NIWA talking up a possible early-season tropical disturbance in account of La Niña in their seasonal outlook, and a universally warm and dry spring:

https://niwa.co.nz/climate/seasonal-cli ... ember-2020

SOI and NINO index heading more and more towards La Nina

its official now. metservie declared it. i hope it gives us good rainfall.

tornado wrote: ↑Mon 14/09/2020 10:01 its official now. metservie declared it. i hope it gives us good rainfall.

USA have declared it as well

tornado wrote: ↑Mon 14/09/2020 10:01 its official now. metservie declared it. i hope it gives us good rainfall.

La Nina will be good for inland thunderstorms/flash flooding. Maybe a few around Auckland.

NZstorm wrote: ↑Mon 14/09/2020 15:33

tornado wrote: ↑Mon 14/09/2020 10:01 its official now. metservie declared it. i hope it gives us good rainfall.

La Nina will be good for inland thunderstorms/flash flooding. Maybe a few around Auckland.

Both Islands?

The BoM's statement today maintains the current La Nina alert with levels just shy of the official BoM La Nina threshold. They look like calling it in October.

http://www.bom.gov.au/climate/enso/outlook/

IMO, At the moment the standing wave needs to nudge east into the western Pacific to help amplify the La Nina north easterlies into NZ, when is the million dollar question but cyclone season could be interesting at the end of January into February.

Serious upwelling now underway at around 100 metres depth in the central equatorial Pacific. Probably why the NASA model is going for a super La Nina within the next 6 weeks like 1973/74. The south Pacific will explode this summer if the standing wave anchors itself in the west Pacific.

should mean good rain for Auckland to save the water crisis
the last big La Nina back in 89 it like rained nearly every day here in January
it might mean a flip flop to a big el nino to follow this, coinciding with an increase in sunspot activity
(my annual rain total going back 60 years here does have a 11 year sunspot signature)

NOAA now going for an all out record Super La Nina in December, surpassing Spring and Summer of 1973 levels. NASA, UK and Access S not far behind in their projections. The weather pattern change in the subtropics around NZ will be extraordinary this summer if this verifies.

Cyclone Tracy wrote: ↑Tue 29/09/2020 21:01 NOAA now going for an all out record Super La Nina in December, surpassing Spring and Summer of 1973 levels. NASA, UK and Access S not far behind in their projections. The weather pattern change in the subtropics around NZ will be extraordinary this summer if this verifies.

Could be a terrible summer for Auckland and much of NZ!

Southland/Central Otago and Manawatu/Whanganui/Taranaki may get a great summer due sheltering from the northeast.

Yes other than inland showers nice and warm potential

BOM declared it now too

NZstorm wrote: ↑Wed 30/09/2020 02:33

Cyclone Tracy wrote: ↑Tue 29/09/2020 21:01 NOAA now going for an all out record Super La Nina in December, surpassing Spring and Summer of 1973 levels. NASA, UK and Access S not far behind in their projections. The weather pattern change in the subtropics around NZ will be extraordinary this summer if this verifies.

Could be a terrible summer for Auckland and much of NZ!

Southland/Central Otago and Manawatu/Whanganui/Taranaki may get a great summer due sheltering from the northeast.

good we need a wet summer. to fill up the dams.

Auckland needs a wet Summer rather than another dry one. We still have water restrictions here at a time of year when we should have plenty of water.

spwill wrote: ↑Wed 30/09/2020 09:33 Auckland needs a wet Summer rather than another dry one. We still have water restrictions here at a time of year when we should have plenty of water.

Totally agree, I do love sunny summer days but really don't want a third consecutive dry summer season. Especially with dams still 23% below normal.

spwill wrote: ↑Wed 30/09/2020 09:33 Auckland needs a wet Summer rather than another dry one. We still have water restrictions here at a time of year when we should have plenty of water.

I would prefer a mild La Nina were we can still get the afternoon convection but not the rainy windy days that can happen with lows from the north.