October Weather Dominated by Wind
Earth Sciences New Zealand reported a notable wind event and storm system on 23 October that caused extensive damage across parts of the South Island and set several temperature records for October.
Impact of Sudden Stratospheric Warming
A sudden stratospheric warming event in September significantly influenced October’s weather in Aotearoa New Zealand. The displacement of air masses led to lower than normal mean sea level pressure across both the North and South Islands, with the strongest pressure drop centered on the South Island. Meanwhile, persistent high pressure remained to the north and northeast of the country.
Strong Westerly Winds and Wet Conditions
The resulting pressure gradient generated strong westerly winds throughout New Zealand. This brought a wet and unsettled month featuring multiple severe gale events, especially in the east and south of the South Island, as well as parts of the lower and eastern North Island.
Temperature Records and ENSO Transition
- The major wind and storm event on 23 October broke several October temperature records.
- During October, ENSO-neutral conditions shifted to La Niña.
- Sea surface temperatures around the north and west of the North Island remained mostly above average.
- Marine Heatwave conditions were mainly observed in the North Island.
“A wind event and storm system on 23 October caused widespread wind damage to parts of the South Island and broke several temperature records for October.”
Author's summary: October's weather in New Zealand was marked by strong westerly winds and storms, influenced by unusual atmospheric pressure patterns and marking a shift from ENSO-neutral to La Niña conditions.