Atmospheric river boosts NZ’s temps by several degrees… but 11 years ago this week it snowed in Auckland
19/08/2022 7:05am
> From the WeatherWatch archives
If you’ve noticed how mild it is at the moment, you’re not wrong. Temperatures across NZ, fuelled by a tropical northerly, are four to eight degrees above normal for what has historically been recorded at this time of year.
It’s an incredible set up and an unusual one. It’s mostly being caused by a very powerful and large high pressure zone to NZ’s east which is reaching up into the tropics, pulling down all the moisture – then blocking it from moving away from NZ.
11 years ago this week a similar large high was parked on the opposite side of NZ, near Tasmania. This opposite set up brought in air from just as far away, but in 2011 it was coming from polar regions. Heavy snow fell to sea level in Dunedin, Christchurch and Wellington while snow flurries even were recorded for the first (and only) time this century in Auckland and on the ranges in the Far North near Kaitaia.
High pressure zones to the east of NZ pull down tropical air due to the anticyclonic flow – whereas highs over Tasmania often dredge up colder southerlies for NZ.
At the start of this month our ClimateWatch update forecast that August would lean warmer than average, despite the wintry blast we had last week (which was forecast). This warm weather will ease into the weekend but for many areas it will still be fairly mild over the coming week.
COMPARING THIS WEEK IN AUGUST… 2011 vs 2022
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Before you add a new comment, take note this story was published on 19 Aug 2022.
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Bart on 19/08/2022 5:10am
Is this unprecedented event earlier this year likely to be related to the amount of rain we have had this year?
https://www.jpl.nasa.gov/news/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere
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WW Forecast Team on 19/08/2022 5:16am
Hi Bart, no totally unrelated. In fact, if anything, the Tonga eruption would generally be cooling things. Remember “weather” is day to day – “Climate” is decade to decade. This fact is now lost in NZ’s media as they clickbait and hype any flood.
Cheers
WW
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Bart on 19/08/2022 8:00am
Did you read the article I linked. I’m well aware volcanoes are typically associated with cooling but in that linked article it says this.
“ In contrast, the Tonga volcano didn’t inject large amounts of aerosols into the stratosphere, and the huge amounts of water vapor from the eruption may have a small, temporary warming effect, since water vapor traps heat.”
Ignoring the warming, as you did, what about the extra water? Do you think that might be associated it’s the extra rain we have been having?
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