NZ Weather Forum

Friday
- very high Tasman sea surface temps.
- high freezing level.
- no Australian bush fire smoke to limit land surface heating.
- light NW winds originating from inland northern Queensland.

What are the possibilities of the long standing record being broken Friday, is there something that i've missed that need to be accounted into as to why the 42.5 deg record wont be under treat ???..?

33C they are forecasting for ChCh tomorrow.
I wonder how hot it will be at NIWA's Riccarton site?

Sea breezes having an influence?

Not sure the incoming airmass is quite warm enough starting off the other side of the Alps.

Late next week has a still-warmer airmass approaching.

32C looks to be the possible max, provided the sea breeze doesn't impose too much. The set up looks a long way off 1973 set up. But you can get local radiation affects on temps if the winds are very light.

I remember that record day in Rangiora it as light to moderate NW, a real bright clear day

Sometimes, in 'hot' type setups the chch easterly sea breeze comes in as a recycled NWer. The standard chch easterly has been really uncharacteristically warm for at least the last month as it is...

Richard wrote: ↑Thu 07/12/2017 21:48 I remember that record day in Rangiora it as light to moderate NW, a real bright clear day

I remember that day as well, also recently when the mercury at Levels Airport Timaru reached 42C, just short of the temperature recorded in the 1973 event. Can't remember the date , will have to consult my diary.

850mb temp chart here for today.

In the 1973 event the 850mb temps were 20C across the country.

other factors to consider

The dewpoint on the West Coast. More moisture leads to a warmer NW.

How dry in the ground? Drier ground leads to hotter temperatures.

just comparing with 7 Feb 1973. Forecast 850 temps for Friday around 16-18 deg, but in 1973 Christchurch midnight sounding had 850 temp of 24 deg and midday on the 7 Feb 850 temp was 27 deg. I recall the day in Pleasant point as being clear with a strong NW at midday and 39 deg. Then a strong southerly arrived with cloud and drizzle and 18 deg by 4pm. NCEP reanalysis map based on 2.5 deg model

I'd imagine you'd have to wait for late January / February to have a chance at beating those 42.4s

So far ChCh Aero has topped out at almost 32 today. Out our side of town we've touched on 35 but dropped back a few degrees with a light northerly breeze in the past hour, currently 30 as at 2:30pm. Awaiting any NW impact

Sea breeze is ruling the roost it seems, unless it drops away 32 might be the max.

Clear to see the NE arrival on my weather station

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So what is NZ's Dec temperature record.

Was at New Brighton today where it was differently a lot cooler then the middle of CHCH, we would have seen much higher temps in CHCH if the NW we have in the Amuri had reached the coast, maxed out here 31deg.

Richard wrote: ↑Fri 08/12/2017 16:47 So what is NZ's Dec temperature record.

Was at New Brighton today where it was differently a lot cooler then the middle of CHCH, we would have seen much higher temps in CHCH if the NW we have in the Amuri had reached the coast, maxed out here 31deg.

See viewtopic.php?f=30&t=5480 for more info.

Regarding your comments about Brighton being a lot cooler than the city, here is a note I had from Dec 2015:
"The most remarkable thing about today’s weather? The temperature at New Brighton was only half of that at the Airport - 18 vs 36!

The Airport broke its December record from 1975, but the Gardens didn’t (its record was also in 1975), falling short by about 3 degrees."

Thanks for that info Tony.

A post from razer Mon 21/12/2015 16:38 See my note above re the easterly today, it was noticeably cooler in town compared to Rolleston, which like the airport has been far enough inland to avoid the sea breeze today. A notably hot NW breeze out there. The NW has not made to the CBD town today, must have been right on the boundary. I note its struggled to reach even 20 at New Brighton today. Quite a remarkable differential


I would have imagine that the sea temps would been cooler that Dec than the current Dec, i was standing by the water today thinking 'man that wind is warm coming off that sea', sort of wind you would get more in Feb

NZ Thunderstorm Soc wrote: ↑Thu 07/12/2017 23:21

Richard wrote: ↑Thu 07/12/2017 21:48 I remember that record day in Rangiora it as light to moderate NW, a real bright clear day

I remember that day as well, also recently when the mercury at Levels Airport Timaru reached 42C, just short of the temperature recorded in the 1973 event. Can't remember the date , will have to consult my diary.

41.3C - see table in this document: https://www.niwa.co.nz/static/web/cante ... d_niwa.pdf

NZstorm wrote: ↑Fri 08/12/2017 06:25 850mb temps.gif850mb temp chart here for today.

In the 1973 event the 850mb temps were 20C across the country.

other factors to consider

The dewpoint on the West Coast. More moisture leads to a warmer NW.

How dry in the ground? Drier ground leads to hotter temperatures.

The ground had been drying out for quite a long time prior to the 1973 event. Not too sure about the "more moisture" - from what I recall from a paper on the event, a parcel of hot air of Australian origin remained disconnected with moister air in the lower layer and got helped by the Alps effect.

The Canterbury irrigation system would make it harder to get a 43C reading I suspect. Wetter ground does not heat up as much as dry ground.

yes that would be true too, less radiating heat from green dairy paddocks than dry land land farming

I suppose that there's no way to know what the Tasman sea temps were in 1973 ?

Well there is Richard .I worked at Metservice in Wellington at Kelburn in 1973 and plotted the sea temperatures onto weather maps. Whether those maps still exist depends if they are stored any where .Certainly we had stores at Kelburn in the basement and up at Upland Road where all the charts and incoming observations were kept .Metservice did not throw away their drawn weather maps . Field books for marine and land observations were all kept going back to when a station opened

Oh ok, would be interesting to know the temps were that year

I worked in Kelburn in 1975, sea surface temps came from ship observations which were plotted on weather maps. I understand that those old weather maps are now in storage at NIWA in Auckland

There were some high maximums in Christchurch in the days leading up to 7 feb 1973.
3rd 30C, 4th 33C, 5th 33C, 6th 28C.

The 43C occurred in conjunction with a front because on the 8th the max was only 18C.

January 1973 was a below average month for max temps at Christchurch. So looks like it was just a synoptic warm event rather than any seasonal situation.