November 2001

Saturday 1 December 2001

Wet in many regions, especially central New Zealand Warm in some northern and western areas Cool in the eastern South Island, especially inland Cloudy in Bay Of Plenty, Wellington and some eastern areas

Variability was a feature of November climate and weather. It was an unsettled month in many central New Zealand areas. Marlborough went from drought to deluge, with rainfall at least double normal. Wellington and parts of Buller also had twice the average November rainfall. It was also wetter than usual in many other regions. A few areas in Hawke’s Bay and parts of north Otago recorded below average rainfall. Rainfall has provided some relief to soil moisture deficits in north Canterbury; however, they remain high for the time of year in some inland areas of south Canterbury and Otago.

Mean temperatures were above normal in parts of Northland, Waikato, northern Taranaki, Wanganui to Kapiti, Buller and Westland. However, the month was cooler than usual in the east of the South Island, especially inland with mean temperatures more than 1.0°C below normal in some areas. The national average temperature of 14.1°C was 0.3°C above the mean November temperature during 1961–1990 and only slightly above the near record high average of October. Sunshine hours were below average in Bay of Plenty, Wellington and some eastern areas, but near average elsewhere.

The overall November climate pattern involved more frequent depressions (‘lows’) than average in the mid-Tasman Sea, which extended troughs of low pressure over the North Island. Pressures were above average to the far southwest and the far east of New Zealand. As with October, these acted to reduce the frequency of the normal spring westerly winds and resulted in more frequent northeasterlies over much of the country.

Wet in many regions, especially central New Zealand

Rainfall was at least double normal throughout much of Wellington, Marlborough and parts of Buller, and at least 120 percent of normal in many other regions. The exceptions were a few areas in Hawke’s Bay and north Otago where rainfall was about 75 percent of normal. Gisborne, the central North Island volcanic plateau, south Westland, parts of Fiordland, and the Otago coast all recorded near average rainfall. Unusually high November rainfall was recorded at Paraparaumu Airport, which totalled 168 mm for the month, 205% of normal and the 3rd highest since records began in 1945.

Warm in some northern and western areas Cool in the eastern South Island, especially inland

Mean temperatures were between 0.5 and 1.0°C above normal in parts of Northland, Waikato, northern Taranaki, Wanganui to Kapiti, Buller and Westland. However, the month was cooler than usual in the east of the South Island, with temperatures about 0.5°C below normal along the coast and between 1.0 and 2.0°C below normal in some inland areas. Mean daily maximum temperatures were 1.0 to 1.5°C below average throughout much of the eastern South Island. Offshore, Raoul Island recorded its 2nd warmest November since measurements began in 1940, with a mean temperature of 20.6°C (1.6°C above average).

Cloudy in Bay Of Plenty, Wellington and some eastern areas

Sunshine and solar radiation totals were below average in Bay of Plenty, Hawke’s Bay, Wellington, Marlborough and Canterbury, and near average elsewhere.

Near or record low November sunshine hours were recorded at:

Location	November sunshine (hours)	Percentage of normal	Year records began	Comments
Whakatane	163	74	1957	3rd lowest

Highlights

Extreme temperatures

• The highest air temperature for the month was 28.4°C, recorded at East Taratahi, Masterton, on the 30th. The highest November air temperature on record for the Masterton area is 29.7°C.
• The lowest air temperature for the month was –3.2°C, recorded at Hanmer Forest on the 5th. The lowest November air temperature on record at Hanmer Forest is –4.3°C.

Tornadoes

• Four tornadoes were sighted on the 4th at Awakeri, near Whakatane, One totally destroyed a hay-barn on a farm, just missing nearby residents.

Significant rainfall events and flooding

• Rainfall totalling up to 85 mm occurred throughout Northland on the 6th. Another event with totals as high as 65 mm occurred over the central North Island on the 13th. Very high rainfalls totalling almost 200 mm were recorded in Fiordland on the 18th. Further high rainfalls resulted on the 22nd, with totals of at least 50 mm in south Auckland, and western Bay of Plenty, and from 50 to 100 mm throughout the Wellington-Hutt Valley region (where slips and surface flooding resulted, causing a few road closures and traffic delays). Water was knee-high on a Newlands Road. Much of the Wellington rainfall occurred within six hours.

High winds

• Storm-force southerlies buffeted Cook Strait, with wind gusts to 198 km/h at Baring Head on the 17th.

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.