General May Weather

[David]

15mm here and easing conditions. Afternoon convergence may produce a heavy shower here.

16.6mm here overnight, warm min of 16C. MTD rain up to 273mm, same amount as January at my location.

[darcyplumb]

Hi all, does anyone know what runway they typically use at Chch Airport in today’s conditions?

[Nev]

Mod Note: Have moved some of this morning's posts about upcoming events to the General June Weather thread.

[NZ Thunderstorm Soc]

Hi all, does anyone know what runway they typically use at Chch Airport in today’s conditions?

The one that points to the NW probably?
Becoming warm here now that the NW Arch has moved over. Up to 21.2C at the moment.

[spwill]

Our afternoon convergence is visible now with towering Cu.

Warm humid conditions here for time of year, 20C currently with a dew point of 17C.

[Razor]

Looks like the Coromandel has taking a hiding with a severe thunderstorm in the last wee while.

https://www.stuff.co.nz/national/waikat ... d-flooding

[David]

Photo of shower clouds to the west late afternoon

[NZ Thunderstorm Soc]

Yes. it looks like a sudden downpour caused a lot of flooding in an area already wet and sodden from recent wet weather brought on from ex TC lows moving across the area over the past few months. Interesting to see what totals fell.

[spwill]

I heard 100mm fell at Waihi Beach today. My sister at Katikati said they had a good thunderstorm there this afternoon.

Isolated heavy showers for Auckland region late afternoon today, a photo of shower clouds over West Auckland.

[NZ Thunderstorm Soc]

Interestingly, a rather warm day today with today's maximum reaching 21.4C this afternoon in warm North to NW wind conditions.
Probably NZ's top unofficial temperature as there is no official site for Geraldine's weather.
Cloudy overnight and this morning with thick NW Arch cloud and light winds.Cloudy evening.

[Nev]

MS recorded 22.0C at Whangarei Aero and 21.6C at Akld's Whenuapai Aero yesterday, which is pretty crazy for the end of May.

[JP.]

Chch aero over 19c today and so far we have had 6 days in May into the 20's. I cannot remember a May as warm as this one, just had a look at the mean temp at Chch aero up to today is 16.09c which is about 7c above normal.

[Bradley]

Chch aero over 19c today and so far we have had 6 days in May into the 20's. I cannot remember a May as warm as this one, just had a look at the mean temp at Chch aero up to today is 16.09c which is about 7c above normal.

Actually only 2C above normal, average max in May for Chch Aero is 14.1C

[spwill]

Chch aero over 19c today and so far we have had 6 days in May into the 20's. I cannot remember a May as warm as this one, just had a look at the mean temp at Chch aero up to today is 16.09c which is about 7c above normal.

Actually only 2C above normal, average max in May for Chch Aero is 14.1C

2C on a monthly average is still a lot temperature and noticeable.

[Orion]

Noticing a handful of large raindrops on northwest-facing window at the moment.
Wind NW, temp.15.7°C

[Razor]

Looks pretty intense in the mountains and on the West Coast right now

Very windy in Lincoln

[NZ Thunderstorm Soc]

Quite windy here this afternoon from the NW especially up in the Downs but the airport AWS at Levels showing a light South breeze?
A couple of pictures from today's NW cloud moving east across the local hills.

[NZ Thunderstorm Soc]

Another mild day here with high cloud and breezy NW winds.
18.6C for today.

[JP.]

Chch aero over 19c today and so far we have had 6 days in May into the 20's. I cannot remember a May as warm as this one, just had a look at the mean temp at Chch aero up to today is 16.09c which is about 7c above normal.

Actually only 2C above normal, average max in May for Chch Aero is 14.1C

Ah yes, got my mean and average max mixed up

[NZ Thunderstorm Soc]

A fine day but with increasing high cloud from the west to end off Autumn.
More mammatus cloud this evening.
17.8C for today.

[David]

A very wet and mild May here.

Total rainfall = 274mm (+158mm, wettest May on record)
Mean temp = 15.1C (+1.2C)
Mean daily max = 18.5C (+0.4C)
Mean daily min = 12.1C (+2.0C)
Highest temp = 22.1C (day 2)
Lowest temp = 4.8C (day 12)
Wet days (≥1 mm) = 19

[Nev]

An exceptionally warm month, which looks likely to be NZ's warmest May on record.
It was, however, also very wet and cloudy for most of the country, with some record rainfalls in the upper North Island.

MetService May 2023 Brief Summary – A wild ride, with Intense Lows

Throughout most of May, New Zealand found itself situated between a large, semi-permanent blocking high pressure system to the east of the Chatham Islands, and slow-moving lows in the Tasman Sea. This synoptic pattern resulted in a recurring series of heavy rainfall events for northern and western regions, reminiscent of the weather experienced during the past summer.

Notably, Auckland [Airport] saw its wettest May since records began in 1962, with 271mm recorded. Kerikeri saw 378mm, the wettest May there since records started in 1978. Kaikohe received a remarkable 585mm of rain, four times May normal, and the wettest May since observations began in 1956.

A significant part of these monthly totals occurred during the first two weeks of May, particularly on the 9th of May when slow-moving thunderstorms lashed the upper North Island, delivering torrential falls of 40-50mm/h from Northland down to Waikato and Bay of Plenty. A local state of emergency was declared in Auckland during this event, and there was one fatality in Whangarei as a result of flash flooding. The west of the South Island also experienced a wet month, with frequent northerly rainfall events bringing double Hokitika’s average May rainfall, with 490mm recorded.

May was unusually mild, with mean temperatures around 1.5 degrees above what is usually experienced during the end of autumn. For many places, some daily highs and lows exceeded 10 degrees warmer than average at times, and these lasted for days on end. This was due to warmer subtropical airmasses transported across NZ by northerly winds, with Southern Ocean cold fronts few and far between.

May 2023 Climate Anomaly Maps ℅ NIWA.png

Preliminary stats for the main centres:

Code: Select all

May 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       18.9  +1.0    12.7  +2.1    15.8  +1.5    232  209%    124   83%
Tauranga Aero           18.6  +0.9    12.0  +2.6    15.3  +1.7    254  218%    
Hamilton Aero           18.1  +1.2     9.5  +2.7    13.8  +1.9    214  184%    117   83%
Wellington, Kelburn     16.2  +1.6    11.5  +2.1    13.9  +1.9    166  115%    107   81%
Christchurch Aero       16.2  +1.5     6.1  +2.2    11.1  +1.8     55   95%    114   81%
Dunedin, Musselburgh    15.5  +2.3     7.8  +1.7    11.7  +2.1     90  141%    114  101%
Greymouth Aero          16.6  +2.1     9.8  +2.3    13.2  +2.2    336  160%     89   90%

* Hamilton sunshine from Ruakura

Note: This was Wgtn's warmest May on record, Akld, Hamilton and Tauranga's 2nd warmest, Dunedin's 3rd warmest, and Chch's 4th warmest.

[NZ Thunderstorm Soc]

min - minus 1 Tuesday the 16th
max - 22.4C Wednesday the 3rd, also Monday the 29th
Highest min - 13.9 Wednesday the 3rd and Thursday the 13th
Lowest maximum - 10C Friday the 19th
Total rainfall was 48.5mm over 16 days.
2 frosts and one thunder clap heard early in the morning of the 27th.
Total rain for the year so far being 312.9mm compared with 209.6mm for Levels, 409.4for Fairlie and 244.4mm for Twizel.

[Nev]

NIWA has confirmed today that May 2023 was indeed NZ's warmest May on record.

This May's national average temp of 13.1C was 0.2C warmer than NZ's previous May record set in 2016.

[jamie]

Of note, the dairy season is June 1 to 31 may. In the 12 months I recorded 1980mm of rain. Our previous highest was 1600 in 17/18 I believe. Our lowest was just a few years ago (think 20/21) at 800 something.
Crazy times to have such a variation in rainfall from year to year.


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