Winter Anticyclone

[NZ Thunderstorm Soc]

Looks likely an intense anticyclone is set to move slowly over New Zealand to end of this month of June.
Interesting to see if it will make it up to 1040hPa.
Anticyclones like this this, sadly, bring frosts and night pollution to many areas.
Also fog and cloud can be trapped under these intense surface pressure conditions which lead to areas having "Anticyclonic Gloom" resulting in drizzle , etc because of no air movement to get rid of moisture in the air.

[Tornado Tim]

Yes John, interesting to see how strong these anti-cyclones are looking, reviewing the longer term prognostics, there is an overall trend that we could see some more very strong anti-cyclones in the next two weeks and a interaction with the sub tropics in between.
The positioning of these ridges is quite interesting, as I was running through some of the model output, the pattern is abnormal. The ridges are forecast to sit well south of where they would typically reside at this time of year. This pattern is more alike to early to mid summer where anticyclones like sitting further south blocking the longwave troughs of the southern ocean.
The trend is exhibited through several model outputs and has relatively good ensemble mean spread through consecutive model runs, so a fair amount of confidence

Example of some extended ECMWF MSLP prognostic

[RWood]

Looks likely an intense anticyclone is set to move slowly over New Zealand to end of this month of June.
Interesting to see if it will make it up to 1040hPa.
Anticyclones like this this, sadly, bring frosts and night pollution to many areas.
Also fog and cloud can be trapped under these intense surface pressure conditions which lead to areas having "Anticyclonic Gloom" resulting in drizzle , etc because of no air movement to get rid of moisture in the air.

Everything has a price, but I'll take the anticyclonic setups anytime. Your neck of the woods (meaning South Canterbury lowlands down to North Otago) gets more cloudiness in summer than in winter, but presumably the summer cloudiness can often be due to easterly flow.

[David]

Another clear calm night but still not cold enough for a frost
Pressure up to 1034 hPa

[Chris W]

Signs are currently that this ridge holds on until around Monday before a low may start making its presence felt next week. Have to say it's great to have so much sun, but some rain for the lakes/farms etc. would be useful.

Weather Underground site for Amberley right now seems a bit high with a reading of 1051.47 hPa!
https://www.wunderground.com/weather/nz ... 172.729634

[David]

Now up to 1035.5 hPa just 0.6 off my record...

[ScottyD]

I’m up to 1036.7 hPa, but then again, not sure how accurate it was when I set it up. Went by other nearby stations and airport obs at the time.

[David]

Not as cold on 4C this morning. Baro now at 1036.6

[Cyclone Tracy]

My station maxed at 1037.7 hPa at 10am. Wobbled back to 1036.9 now. Latest EC and Access R runs suggest that pressure will go through the 1038 hPa barrier on Saturday morning across the Upper NI and breach 1040 hPa in parts of the NI and SI.

[harleyb]

Abnormal or not, I'll take it. Stunning winter weather. Here's a pic I took yesterday on my way out to Kapiti Island. Way too nice to be at work.

DSC035651.JPG

[Orion]

^ just about glassy!

[midgrove]

ERA-5.jpg

Tara Hills (Omarama) recorded 1041.7 at 9am this morning and Queenstown 1040.0, a "cold high" was drawn on the 0600hr MetService analysis this morning. Apparently the all time record was 1045.9 in Wellington in 1889. on the 2nd September 2008 the ECMWF reanalysis showed a high with 1048 isobar east of New Zealand

[David]

Peaked at 1038.1hPa here near midnight

[Nev]

Highest pressure recorded by NIWA was 1043.2 hPa at Motu, Gisborne this morning for this BFH...

It's official: the high pressure system anchored over New Zealand is one of June's strongest ever!

On Saturday morning, the mean sea level pressure at Motu, Gisborne reached 1043.2 hPa, the highest value observed in the North Island during June on record.

This represents New Zealand's 3rd highest June "pressure day" overall.

5 June 2016, 1044.7 hPa, South Island
28 June 1989, 1043.9 hPa, South Island
29 June 2019, 1043.2 hPa, North Island

Other notable max sea level pressures from Saturday morning (hPa): Auckland 1037.5, Hamilton 1040.0, Ohakune 1042.8, Taumarunui 1041.2, Wellington 1037.4, Napier 1040.1, Gisborne 1039.9.

>Ben

[NZ Thunderstorm Soc]

Interesting article on the front page of this morning's Timaru Herald about the anticyclone.
A local resident in Twizel recorded a reading of 30.7 inches on his dial aneroid barometer yesterday saying that that was his highest reading in the 25 years he has been living there.
Apparently 30.7 inches equals to 1039.6 hPa in modern day terms.

[Bradley]

2C at Christchurch Airport at 6pm, Metservice only predicting -1C tonight though, they must think a decent breeze is going to spring up at some point in the next few hours? Going to the Crusaders vs Hurricanes game tonight, hopefully the temperature doesn’t keep going down at the rate it has or it could be below freezing by kickoff!!