NZ Weather Forum

Dull day here today.

Stunning day inland, magic day round the Culverden area this arvo.

Misty/foggy all the way from Ashburton to Westerfield to Mayfield this morning.

melja wrote:Stunning day inland, magic day round the Culverden area this arvo.

It was, we were in CHCH most of the day where it was so hazy, coming back once going over the Weka pass the air was so clear thanks to the light NW wind

Fog/low cloud all day yesterday with a crappy high of only 6.5C

mondays' sub tropical low for NI starting to take shape now on sat image in north tasman

Manukau heads obs wrote:mondays' sub tropical low for NI starting to take shape now on sat image in north tasman

A moisture punch with this system so some heavy rain for many!
A low thunder risk for overnight Monday for the north and snow for McKenzie country in the south!

How cool is the new 10 min sat images. Met service put them on their Facebook page a few times

ps, thought I heard thunder a little while ago from that slow moving frontal active shower line sitting over us
(9mm from it), which is looking like moving onto the city CBD soon

yup, those sat image animations are neat

A great day here today - cloud and mist cleared to a balmy 19.1°C day so far.
Very glad that winter is drawing to a close....

Lovely here too, but has started to cloud over about 3.00

My station's readings for the month:

Ave temp 7.3°C
Ave Minimum 2.5°C
Ave Maximum 12.9°C
Minimum -2.2°C on 21st (6 air frosts + 3 days <1°C)
Maximum 23.3°C on 3rd
Rainfall 46.8mm from 12 days with 19.6mm on 15th, YTD 335.2mm

Slightly cooler (0.3C) than the mean for August. 1-2cm snow settled overnight 7-8th and there was a dusting on the morning of the 9th.

A cooler than normal August overall. The dry in North Canterbury continues. Sunny for most areas, except for the SW of the North Island and NW of the South Island.
Some preliminary August 2015 figures for the main centres:
Note: In the 24 hrs to 9am this morn, Mangere recorded 60mm, Ak Aero 40mm and Tauranga 47mm.

About average for rainfall in Howick for August, temperature maybe a bit lower than average. Key stats:

Avg temp 11.1C
Avg max 15.3C
Avg min 7.1C
Highest 19.1C
Lowest 0.9C
Rainfall 125mm

Ave temp 6.0°C
Ave Minimum 0.6°C
Ave Maximum 11.4°C
Minimum -3.3°C on 21st (19 air frosts)
Maximum 20°C on 3rd
Rainfall 52.2mm from 12 days with 20.1mm on 15th, YTD 382.mm

The westerly pattern dropping out for the last week of August, quite a wet but warm last few days here, grass growing weather .

Here's NIWA's preliminary, 'August National Climate Summary'.

A cool month in the south and dry in the east.


The national average temp of 8.6C was 0.2C below normal.

The month's highest temp of 23.8C was again recorded at Christchurch (Riccarton) on the 3rd, and the lowest temp of -11.5C was recorded at Tekapo Aero on the 11th.

That Riccarton site has got to be seriously contaminated by poor exposure. If you have a look on Google Maps you can see its surrounded by asphalt carparks and concrete buildings, and seriously under exposed to the wind. The only thing its got going for it is straight-line distance to the Botanic Gardens, the physical environment around it is totally different. You could argue its representative of the urban environment, but as a point of comparison to previous readings at the Gardens or other stations around New Zealand its not satisfactory.

Gardens site closed? Pity about comparison issues.

I think readings from the Botanic Gardens site are still taken by Chch City Council, but only passed on to NIWA on a monthly basis. Not surprisingly, NIWA's nearby Riccarton HQ site generally records a little more extreme T-maxs and T-mins than the Gardens site (ignore the 1981-2010 normals, as Riccarton only has a 13 year history).

I also don't agree with NIWA's current practice of lumping one site (especially a questionable one) alongside others in the region for comparison in their summaries, e.g. saying that that 23.8C Riccarton reading was Chch's highest August temp since records began in 1863. You can always find a warmer (or cooler) site than those generally used to represent a region. I believe some councils unhappy with the temps shown on TV have in the past paid MetService to set up a more flattering site. Jim Salinger used to refer to this practice as 'temperature for tourism'.

Nev wrote: I believe some councils unhappy with the temps shown on TV have in the past paid MetService to set up a more flattering site. Jim Salinger used to refer to this practice as 'temperature for tourism'.

Yes Kaikoura is a great example, there recording site was moved from out at the point to now situated at the foot of a north facing bank.

Do you mean from a point out on the Peninsula to somewhere near the town?
Other places have had temperatures recorded away from the towns like Timaru at Levels and Hilderthorpe was where Oamaru temperatures were recorded.

[quote="NZ Thunderstorm Soc"]Do you mean from a point out on the Peninsula to somewhere near the town? Yes in the middle of town, i'll find out where. TV1 &TV3 should only be using data from sites that meet WMO standards otherwise its just as actuate as say using Mr&Mrs Smith gauge that may be situated in there sun porch or somewhere similar.

Nev wrote:I think readings from the Botanic Gardens site are still taken by Chch City Council, but only passed on to NIWA on a monthly basis. Not surprisingly, NIWA's nearby Riccarton HQ site generally records a little more extreme T-maxs and T-mins than the Gardens site (ignore the 1981-2010 normals, as Riccarton only has a 13 year history).

I also don't agree with NIWA's current practice of lumping one site (especially a questionable one) alongside others in the region for comparison in their summaries, e.g. saying that that 23.8C Riccarton reading was Chch's highest August temp since records began in 1863. You can always find a warmer (or cooler) site than those generally used to represent a region. I believe some councils unhappy with the temps shown on TV have in the past paid MetService to set up a more flattering site. Jim Salinger used to refer to this practice as 'temperature for tourism'.

They say they can't do proper comparisons in the short timespan involved (i.e. getting out the monthly report not long after that month has ended). But some silly results are therefore inevitable. The sunshine climatology is worse and a false impression of above-normal values is frequently being created because sites with EWSs are being compared with their old versions. Silliest of the lot is Q'town Gardens manual vs. Q'town Aero EWS - considerably different exposures plus recording method change. So "Queenstown" is breaking or threatening a lot of its old records in the shorter daylight months particularly.

But even decades ago in the 1950s there was an issue with sunshine normals not acknowledged at the time - the averages to 1950 contained a lot of suspect pre-1935 or pre-1930 data, most of it flattering to the sites concerned, most notably Napier. In addition the 1935-1950 period was clearly somewhat sunnier than in the long term, especially in the North Island. Result was exaggerated deficits shown in many of the 1950s years, including 6 consecutive years 1951-1956 and the comment in the annual summary for 1957 that for the North Island it was the first year since 1947 with average or above-average readings for the whole island. In addition there was a typo or miscalculation for Alexandra, giving it a mean 27 hours above the correctly calculated value. When revised normal 1935-1960 were published, Napier's value dropped by 125 hours from the old one.

Winter summary from Niwa
https://www.niwa.co.nz/sites/niwa.co.nz ... 0FINAL.pdf
Auckland & Hamilton sunnier than Tauranga.

I think Auckland had a more stable Winter than usual, local rainfall boosted by some short duration rainfall events.

Plenty of snow this Winter but no major snow storm.