9-14 Feb Subtropical northerly flow, embedded troughs

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tunster
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by tunster »

tunster wrote: Sat 10/02/2018 11:11 On the weather front, tomorrow should see widespread 22C-23C dewpoints over Northland and Auckland. It will be interesting if anywhere reaches 24C. 24C is the highest dewpoint I've seen in NZ, but that's from memory not the record books. I wonder what the record high dewpoint is for NZ? (excluding Raoul Island).
Highest dewpoints in the last 60 hours, excluding Raoul:

Whakatane 24.0C
Gisborne 24.0C
Mahia 23.8C (elevated station: 136m high)
Kaitaia 23.8C

....the list goes on

Two curious readings I found are Wainuiomata and Lower Hutt. The former recorded a dewpoint of 23.6C yesterday afternoon while Lower Hutt actually would take the national record of 25C at the same time. There had been low cloud, some rain and northerlies during that period. Wellington Airport hit 22C, probably the highest dewpoint since 2011.


Some interesting combinations of temperature and dewpoint are in Auckland and Gisborne, the latter is currently 28/24. Those are genuine tropical conditions: when I was in Kerala during the SW monsoon last year, it was 28/24 mid-morning which felt incredibly refreshing compared with conditions like 36/27 which seems to be what Chennai gets everyday for half of the year.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by spwill »

The general dewpoint for Auckland today looked to be in the 22--23.5C range.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by jamie »

Haha this is silly. Metservice 2hrly forecast for where I live shows 200mm in the next 24hours. This thing jumps around more than a kangaroo!
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by NZstorm »

jamie wrote: Mon 12/02/2018 19:24 Haha this is silly. Metservice 2hrly forecast for where I live shows 200mm in the next 24hours. This thing jumps around more than a kangaroo!
A little bit cooler aloft tomorrow so as that front moves across a few cb tops to 11km likely.


A shortwave moving across Otago tomorrow triggering a thunderstorm or two over east Otago. Shortwaves tend to be the little bit of magic for storm development so I suggest a decent risk there.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by spwill »

A few thunderstorms occuring over Northland tonight with the front firing up.
A muggy night here, still 23C, dp is 21C.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by jamie »

Thunder rumbling away here rather frequently. Radar shows the trough really starting to fire up
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Tornado Tim »

Yup thunder, some good development....
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Cyclone Tracy »

Quite a few sparks around Northland this morning. Latest MS synoptic has the trough stalling today right down the Upper NI into central NI with the TC Gita link still in place. Another 10mm so far this morning here.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by NZstorm »

Some lightning from Northland to Hawkes Bay this morning. 11mm here so far in Grey Lynn.

The storms will be elevated and 300mb divergence triggering them along the front. Looking like the subtropical jet across North Island providing the divergence.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by jamie »

34mm since midnight for me. 20 fell in an hour at one point.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by David »

Looks like a very wet day coming up. Whangarei showing 20mm last hour.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by David »

Thunder heard to the east of here.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Nev »

Been quite a bit of really loud thunder and lightning out here over the last 30 mins…
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by spwill »

The trough has really cranked up, thunderstorms from Northland, through the Firth of Thames into Waikato overnight, thunderstorms in the Gulf currently.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Cyclone Tracy »

Cloud tops around -50c now in upper NI. Steady rain here.

Issued by MetService at 7:12am Tuesday 13-Feb-2018
Heavy rain for parts of the upper North Island today

A moist northeast flow lies over the North Island today and an active trough within this flow extends from Northland through to Hawkes Bay, delivering heavy rain, isolated thunderstorms and downpours. The trough is expected to weaken this evening and the rain and thunderstorm activity should ease.

This Watch is for the possibility of rainfall amounts reaching warning criteria in Auckland, Waikato, Waitomo, Taupo, eastern parts of Taumarunui and Taihape including Tongariro National Park, and Hawkes Bay between about Tutira and Waipawa.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Twister sista »

Thunderstorm currently in te aroha
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Cyclone Tracy »

Just had a peak 109.8mm/h rate. Mostly moving between 20 to 40mm/h over the last 10 minutes. 25mm for day so far.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by David »

Yes, had a torrential fall in Howick too, peaked at 93mm/hr. Good day to be working from home...
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Cyclone Tracy »

Another couple of mm gives 27mm for the day. 126mm for the event so far.

Might squeeze some more in tomorrow as well.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by David »

And yet another severe weather watch for tomorrow. Maybe the trough is going to intensify again - pretty much fizzled out this afternoon
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by spwill »

Another burst of heavy showers/rain with a SW wind change to slowly move through tomorrow.
Fine & sunny here for Thurs/Friday with the dewpoint a little more comfortable around 18C by then. :>
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by spwill »

See where the temp/humidity can go today, currently 25C with a dewpoint of 22C for Auckland.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by Cyclone Tracy »

Got to 26.1c and a DP 22.8c a short while ago before cloud closed in. Now 25c, DP 21c.

Downloaded my data logs for this week and noticed I hit a DP of 24.4c at 1.30pm on Monday Feb 12th. That record for my PWS will stand for a long time to come I would think.
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Re: 9-14 Feb Subtropical northerly flow, embedded troughs

Unread post by jamie »

Interesting that there appears to be a sea breeze convergence of showers right up the west coast of the northern NI and there is also the main trough.
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