MetService National weather: December 18th - 20th.
Much of central New Zealand could be in for a wet Christmas as a new rainmaker forms in the Tasman Sea next week.
MetService forecaster Tahlia Crabtree said while the immediate focus was on Tropical Cyclone Yasa, modelling showed the destructive storm tracking well away from our shores with a new low forming in the nearby Tasman Sea.
This was expected to move onto the centre of the country in the middle of next week.
It threatened to bring rain to central and lower parts of the country, with most models reserving the heaviest downpours for the West Coast of the South Island.
Although it wasn't a tropical-cyclone-related low, Crabtree said very warm air remained near New Zealand, possibly fuelling rainfall and adding complexity to the situation.
"When you've got systems like this, where every model they do something different, it's always the closer you get the clearer it becomes.
"Over the weekend we'll have a better confidence of that but it's definitely looking very likely that's what will bring rain during next week, not a tropical cyclone."
In the meantime, the destructive cyclone appeared to be on track to weaken and move well away from New Zealand.
Crabtree said two of three models that forecasters referred to had the Yasa's projected track heading nowhere near New Zealand.
The category 5 storm, that has swept over Fiji, flattening villages with destructive 350km/h winds and monster surges, was looking likely to weaken and eventually become a low-pressure system.
"All the models are speaking of a low probability that any low-pressure system that is related to that cyclone will move near New Zealand," she said.
Crabtree said when it came to sailing on Auckland's Waitemata, it was going to be a great weekend to be on the water, with fine days and temperatures in the mid 20s.
She said the days would be book-ended by cloudy skies but overall it would be great outdoor weather.
Christmas Day might not end up being so gloriously fine for much of New Zealand. Photo / 123RF
"There are northeasterlies during today and tomorrow but we're expecting relatively light winds for the weekend.
"I guess in terms of sailing, you'll probably get your afternoon sea breezes picking up but the winds aren't looking particularly crazy.
"I imagine the sailors will probably want more wind but they'll have to play with the sea breezes that occur."
