General September Weather

[mikestormchaser]

Another interesting little event for Canterbury over next day or two. Low risk of a thunderstorm tomorrow with S change. But doesnt looks as good of a set up as last week. Seems like alot of thick high cloud cover tomorrow with even a spot of rain in morning.

[NZ Thunderstorm Soc]

Not expecting anything down here tomorrow, Mike.

[NZstorm]

An area lightning west of the North Island currently looks like tracking down into Waitomo possibly southern Waikato.

[NZstorm]

Tomorrow looks like the first spring hail set up and some of the horticultural regions could be affected. Looking like Nelson and Hawkes Bay/Gisborne the most exposed to a localised hail downpour.

Hail and storm activity tomorrow will be proportional to the amount of surface heating that can occur.

500mb chart midday tomorrow.

500mb chart.gif

[mikestormchaser]

Tomorrow looks like the first spring hail set up and some of the horticultural regions could be affected. Looking like Nelson and Hawkes Bay/Gisborne the most exposed to a localised hail downpour.

Hail and storm activity tomorrow will be proportional to the amount of surface heating that can occur.

500mb chart midday tomorrow.

500mb chart.gif

Im not convinced for storms down this way with the thick high cloud about today. Then again wev seen things happen.

[NZ Thunderstorm Soc]

I wouldn't bet on it. Boring low cloud here today and not a hint of any precipitation.
Edit: drizzly rain falling now with hardly any wind if so from the east.

[TonyT]

A couple of peels of thunder here in the last 10 minutes. Storm is trying to get going, coming on to rain now.

[Richard]

I was looking at those clouds thinking they were starting to look interesting

[Chris W]

Thunderstorm in Amberley, torrential rain and intense hail..and after about 10 minutes of action it's gone.

Pleased to break my lightning/thunder drought

[melja]

Fizzer in Rangiora, no rain.

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[Richard]

Unfortunately that drought still happening in some localized areas, like bloody here

[NZ Thunderstorm Soc]

.....and here

[Chris W]

Truly sorry, but some people in this forum get them virtually every week so I regret nothing!

Looks very interesting near Ashburton again, must be snowing to about 100m again?

[Dean.]

Light rain and 7 degrees in town looks like a heavy rain/hail storm 30km south of here on the radar.

[Chris W]

Something incoming for the city, I'm in Parklands looking at some dark cloud to the SW.

[Chris Raine]

Heavy rain out of a Cb in Thornbury 4.7 C with small hail currently

[Thunder081]

Wellington

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[Cyclone Tracy]

September 2019 stats –

Mean daily temp = 13.5 (around 0.5c above normal) Max 17.4 Min 10.2
Rainfall = 118mm (12mm above local average)
Prevailing wind WSW
2 thunder days.
YTD daily mean temp = 16.1c (Around 1c above normal). Still 0.2c less than to 30 September, 2018.
YTD rainfall = 649mm. 268mm under local average of 917mm to end of September.

No new records

[David]

September 2019 stats for Howick

Mean temp 12.8C
Mean daily max 17.0C
Mean daily min 9.2C
Highest temp 19.9C (29th)
Lowest temp 5.3C (1st)
Total rainfall 130mm, YTD 882mm

[Richard]

Sep stats
max temp 21.3 29th
min " -2.4 8th
lowest max 7.3 8th
highest min 11.4 23r
rainfall 38.8mm
rainfall to date 373.4mm
thunder days Bloody zero

[Awhituobs]

my sep report or my location
http://weather-display.com/windy/gb/cli ... 92019.html
much wetter than normal here . Temperature overall average (average is for last 15 years)
windspeed up on normal

[Richard]

my sep report or my location
http://weather-display.com/windy/gb/cli ... 92019.html
much wetter than normal here . Temperature overall average (average is for last 15 years)
windspeed up on normal

Your snowfall list doesn't get much of a workout Brian, has it ever snowed there?

[Awhituobs]

haha..actually yes, there has been brief snow flurries here before...even Queens Street in the auckland CBD has has brief snow flurries

https://www.nzherald.co.nz/nz/news/arti ... d=12107973

[cbm]

My stats
Average daily - max 17.1 min 6.8
Month average 11.95
Min +1.4 1st
Max +20.4 5th
Rain: 90mm
Rain YTD 562.6 (Still well below average, must be high odds of less than 1000mm for the calendar year)

[Nev]

MetService September 2019 Summary - 'Unusually cold':

During the first few days of September, a Tasman Low produced warmer, wetter weather for northern New Zealand (Tauranga northwards), as well as Nelson and Marlborough. It was subsequently a wetter than usual September for parts of Northland, Auckland, Coromandel and northern Waikato, also Nelson and Marlborough. Elsewhere, cold, showery weather resulted in monthly rainfall totals that generally ranged between 60 and 100 percent of September normal.

By the 5th of the month, however, persistent cold southerlies kicked in across the country. These unseasonable cold outbreaks continued through the month, producing an extremely cold September for southern, eastern and northern parts of the South Island. Temperatures were also below average for the western South Island, as well as around Wellington and the Wairarapa. For the remainder of the North Island, monthly temperatures were closer to normal.

Sudden Stratospheric Warming (SSW) occurred in early September over the southern pole, but impacts have failed to penetrate down to the troposphere (where the weather occurs). Recent cooler temperatures over New Zealand have not been influenced by the SSW, but instead have been driven by frequent Southern Ocean southerlies washing up and over New Zealand, as per MetService forecast.

Sep 2019 Climate Anomaly Maps ℅ NIWA.gif

Some very preliminary Sep 2019 figures for the main centres:

Code: Select all

Sep 2019 Average Temps, Rainfall, Sunshine and departures from 1981-2010 normals ℅ NIWA

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

Auckland, Mangere       16.7  +0.4     9.9  +0.3    13.3  +0.3    123  120%    180  119%
Auckland Aero           16.7  +0.3    10.0  +0.3    13.3  +0.3    126  140%
Tauranga Aero           16.8  +0.2     8.9  +0.6    12.8  +0.4     97  115%    n/a   n/a
Hamilton Aero           16.5  +0.2     6.5  +0.3    11.5  +0.2    124  123%
Hamilton, Ruakura       16.5  +0.1     7.2  +0.5    11.8  +0.3    151  164%    146  100%
Wellington, Kelburn     13.7   0.0     8.0  +0.1    10.8   0.0     78   79%    167  102%
Christchurch Aero       15.2  +0.4     3.7  -0.2     9.4   0.0     55  135%    185  109%
Dunedin, Musselburgh    13.4  +0.2     4.7  -1.2     9.1  -0.4     39   80%    202  150%
Greymouth Aero          13.7  -0.4     6.2  -0.4     9.9  -0.5    194   93%    153  115%

NIWA's 7SS national average temp this Sep looks likely to be about 0.1C below its 1981-2010 average (as was last April), therefore well within NIWA's ±0.5C definition of 'normal'.

So quite a changeable year so far, with 4 near-record warm months (Jan, Mar, May & Jul), plus a warmer than 'normal' Feb, and 4 months that were within 0.1C of average (Apr, Jun, Aug & Sep).