TL;DR:
- The weather pattern for New Zealand and Australia this summer is primarily influenced by El Niño, depicted as a canvas painted orange, with unexpected rain and downpours represented by blue splatters.
- High-pressure zones are smaller than usual over New Zealand, leading to varied weather conditions and the “Swiss cheese effect” of dry and wet areas within regions.
- February brings cooler mornings and a mix of weather, including a temporary autumnal blast, but warmer temperatures are expected to return with nor’westers from Australia.
Envision the upcoming month’s weather as a vast canvas, with El Niño providing a vibrant orange backdrop. This vivid base sets the stage for our summer weather expectations across New Zealand and Australia.
However, the season’s narrative takes an unexpected turn with the addition of blue splatters across the canvas, symbolising the surprising rain and downpours that have marked parts of both countries this summer.
This artistic analogy helps us grasp the dual-layered nature of our current weather conditions. The expected pattern includes more westerly winds and drier areas, especially to the east or inland. Yet, this hasn’t been universally the case, particularly in the eastern North Island, where regions like Hawke’s Bay have experienced unusually green landscapes for several years.
A notable challenge this summer is the diminished size of high-pressure zones over New Zealand, akin to fitting a single bed’s high-pressure zones over a double bed.
This mismatch results in varied wind flows and weather patterns around the country’s edges, leading to more frequent rain events in the North Island. The “Swiss cheese effect” describes the patchwork of dry and wet areas within regions, currently observed in Waikato, Canterbury, and Southland.
As we step into February, the days begin to shorten, a change most noticeable in the later sunrise each morning. Despite the cooler mornings ahead, summer’s warmth hasn’t bid us farewell just yet.
The season’s character was briefly challenged by an “autumnal blast” during the first weekend of February, but temperatures are set to rise again, thanks to nor’westers from Australia.
However, the snug fit of high-pressure zones over New Zealand remains elusive, and the Southern Ocean’s stormy state promises more windy westerlies and cold fronts for the South Island. The tropics are currently a whirlwind of low pressure, reminiscent of La Niña conditions, with computer models predicting the formation of a tropical cyclone in the Coral Sea, potentially the third this summer.
While high pressure near northern New Zealand is expected to shield us from the storm, Queensland might not be as fortunate. Another cyclone could emerge around the Cook Islands, adding to the season’s unpredictable narrative.
This week’s weather highlights include dominant high pressure over the North Island, intermittent westerlies for the lower half of New Zealand, a cooler southerly by Thursday, and the arrival of high pressure this weekend, painting a complex but fascinating picture of our summer weather.
