Warm October despite rain
DESPITE wet and windy weather in Southland during October, Niwa’s records show it was New Zealand’s fifth warmest October on record, and the warmest October since 2001.
Niwa meteorologist Seth Carrier said the prevalence of high pressure to the northeast of the country, resulted in a dry month across much of the South Island, where rainfall was below normal or well below normal.
‘‘Conversely, periodic westerly winds brought several moisturerich fronts to the west and south of the South Island, resulting in widespread above normal (120%149% of normal) rainfall for the West Coast, Southland, and Stewart Island.
‘‘In fact, South West Cape on Stewart Island had its wettest October since records began in 1991, with 182mm — 172% of its monthly normal rainfall.’’
On October 4, up to 60mm of rainfall caused flooding to properties in Riverton, Invercargill, Otatara, Winton, Mokoreta, Wyndham, Gore, Fortrose and Tokanui, while slips were reported in the Catlins and Stewart Island.
He said Stewart Island also recorded New Zealand’s strongest wind gust for October 2020 and the island’s second strongest gust on record, when 172kmh was observed on October 3 and 25.
Mr Carrier said the high pressure and northerly quarter winds were also an ‘‘ideal recipe’’ for warm temperatures, resulting in above average and well above average temperatures across nearly all of the South Island, except for parts of eastern Otago where temperatures were near average.
Overall, the nationwide average temperature was 13.2degC during October 2020 — 1.2degC above the 19812010 October average, making it New Zealand’s fifth warmest on record, and the warmest October since 2001.
‘‘It has now been 45 consecutive months since New Zealand’s nationwide average temperature was below average.’’
He said westerlies brought especially warm air across the Tasman Sea around October 5 and again on October 25.
On October 25, Lumsden (24.6degC), Tiwai Point (23.5degC) and Nugget Point (26degC) recorded their second highest October temperatures, and Dunedin (29.1degC), Five Rivers (24.5degC) and Balclutha (26.1degC) recorded their third highest.
‘‘Notably, on October 5, Wairoa reached 30.8degC, which is the third year in the last decade that New Zealand observed a temperature more than 30degC, in the month of October.’’