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Re: General February Weather

Posted: Thu 02/03/2023 13:26
by Nev
February 2023 will be remembered for extreme rainfalls around much of the North island with many records broken.
MetService February 2023 Brief SummaryAn extreme month, dominated by Cyclone Gabrielle

In a summer that never really got going for the North Island, February brought more of the same - extreme weather related to Cyclone Gabrielle 12-15 February, followed by several downpour events. In contrast, the lower South Island experienced an extremely hot, sunny and rather dry February, until a rain maker brought some drought relief on the 21st/22nd, followed by an unseasonably cold change that resulted in summer-time snow falling on the southern ski fields.

Cyclone Gabrielle (12 – 15 February) will go down as one of New Zealand’s worst storms in recent memory, and the most severe since Cyclone Bola in 1988. On the back of a record-breaking wet January, impacts were widespread and devastating across the northern and eastern North Island.

To give insight into the extreme intensity of Cyclone Gabrielle, a MetService weather station at Great Mercury Island recorded air pressure of 966.7hPa on the 14th. This ranks in the lowest 10 air pressures ever recorded in the North Island (the record is 962.9hPa at Cape Reinga in 1851).

A nationwide State of Emergency was declared on 14 February, as Cyclone Gabrielle lashed the North Island – only the third time such a declaration has been made in New Zealand’s history. The declaration was issued to support six regions that had already declared a Local State of Emergency: Northland, Auckland, Tairāwhiti, Bay of Plenty, Waikato, and Hawkes Bay.
(For a regional summary, see https://blog.metservice.com/TropicalCyc ... lleSummary).

Gabrielle wasn’t the only high intensity rain event for the North Island - downpours affected the upper North Island on multiple occasions in February. The New Zealand low-elevation 1 hour rainfall record was under threat several times; a particularly active thunderstorm day on 24 February saw 79mm fall in 1 hour in north Auckland producing further flooding. Another thunderstorm also brought a tornado to Waihi on the morning of the 25th.

(The 1 hour low-elevation rainfall record is 109 mm, recorded at Leigh, 20 May 2001)
Feb 2023 Climate Anomaly Maps ℅ NIWA.png

Preliminary stats for the main centres:

Code: Select all

Feb 2023 Average Temps, Rainfall, Sunshine and departures from 1991-2020 normals ℅ NIWA

Site                     T-max °C      T-min °C      T-mean °C     Rain mm      Sun hrs

Auckland, Mangere       23.6  -0.4    16.5  +0.1    20.1  -0.1    190  337%    188   93%
Tauranga Aero           23.4  -1.0    16.7  +0.9    20.0  -0.1    231  278%    
Hamilton Aero *         23.9  -1.1    14.5  +1.4    19.2  +0.1    127  176%    177   96%
Wellington, Kelburn     20.9  +0.3    15.1  +1.2    18.0  +0.7    198  356%    170   80%
Christchurch Aero       23.6  +1.4    13.0  +1.5    18.3  +1.4     94  235%    216  111%
Dunedin, Musselburgh    21.4  +2.7    13.6  +2.1    17.5  +2.4     34   48%    243  145%
Greymouth Aero          23.4  +3.6    14.6  +1.9    19.0  +2.7    114   72%    234  121%

* Sunshine from Ruakura 

Re: General February Weather

Posted: Thu 02/03/2023 17:54
by Nev
Below are some record or near record Feb rainfalls from MS. Note that Feb was Gisborne Aero's wettest all time month (following its wettest Jan) and Napier Aero's wettest Feb (following its wettest all time month in Jan).

Re: General February Weather

Posted: Fri 03/03/2023 21:26
by NZ Thunderstorm Soc
February readings from Geraldine.

min - 3.6C Sat 25th
max - 33.6C Friday the 3rd
Highest min - 20.2C Sunday the 5th
Lowest maximum - 15C early morning of Thurs the 23rd although the daytime maximum only reached 10.5C.
Total rain fall was 58.5mm over 11 days.