As far as any expected rainfall goes “a wetter than normal winter looks pretty unlikely”.
However, Chris says for the next few days there were good indications of some much-needed rain over the lower North Island.
“It’s certainly not etched in stone.”
He says as we get into the week, there will be a low out in the Tasman Sea which will move back toward us.
“That will likely result in some meaningful rain for much of the Tararuas.
“There could be some pretty good rain in fact and that would go a long way into kind of taking the edge off in terms of dryness.”
However, it may not be enough to resolve issues brought about by the long dry spells of the last few months.
And if there is too much rain all at once, it could result in flooding.
“Ideally in a perfect world what you would want is kind of successive sustained episodes of rainfall of light to medium or even occasionally heavy, not but overly heavy.
“You don’t want the real high-intensity heavy rain coming in a short period of time because what that will result in is simply a lot of run-off and a lot of that rain doesn’t get absorbed into the ground.”
Chris says winter is an important time of year because it’s the time “where we have what’s called groundwater recharge where we’re basically replenishing all the water that’s left the ground”.
“It’s the time of year when we really want to replenish what has been removed during the warm season and the growing season and if that doesn’t happen properly, then you’re walking into another dry or a warm season or growing season kind of behind the 8-ball.”
Chris says hopefully that can happen, but it’s not looking overly wet for the next couple of months.
Meantime, El Nino has been left behind, but La Nina has yet to make an appearance, leaving the country in a neutral state, referred to as Enso, or El Nino southern oscillation.
He says all three are known as climate drivers and can give meteorologists clues as to what weather outcomes are favoured.
“It doesn’t guarantee them, but it loads the dice for certain outcomes.”
La Nina is unlikely to make an appearance during the winter season, but there is a fairly good chance it will take hold during spring.
“As we get maybe towards the end of winter and certainly into spring, we may start to see more weather patterns that are a bit more aligned with La Nina.”
While for much of the country that tends to mean more easterly or northeasterly winds, generally bringing higher chances for rainfall, it could be different for the Tararuas.
Chris says that doesn’t mean we should be alarmed or concerned, but it does underscore the need for getting the required rain over winter.
“Because if La Nina does take hold and it’s springtime and especially summer time and La Nina is well and truly here that could increase the odds for dryer weather for the lower part of the North Island, including the Tararua [District] because of the air flow that usually happens with La Nina, coming from the east and northeast, then that kind of wind direction is coming off the land, not so much the water and that tends to not give us very wet weather.”
However, Chris emphasises that every La Nina or El Nino is different, but they can give insight and are helpful for understanding what weather outcomes or themes are likely to emerge, although there are no guarantees.
