Convection Period 1st - 4th Jan

[RODALCO]

View from our Titirangi deck looking over the Waitakere Ranges NW.
Hear the first rumble too.
Time 14:14 hours.

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[spwill]

The same Cb from Mt Eden.

[RODALCO]

Lots of moisture in the air. On our deck out of the wind and in the shade it is 29 degrees C.

[tgsnoopy]

The latest watch:

http://www.metservice.com/warnings/seve ... torm-watch

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SEVERE THUNDERSTORM WATCH

Issued by MetService at 01:36 pm Tuesday 02 January 2018
Valid until 10:00 pm Tuesday 02 January 2018
This watch affects people in the following weather forecast districts:
Auckland
Coromandel Peninsula
Waikato
Waitomo
Taumarunui
Bay of Plenty
Rotorua
Taupo
Gisborne
Hawkes Bay
Taranaki
Taihape
Wanganui
Manawatu
Tararua
Wairarapa

Scattered heavy showers and thunderstorms have developed over the North Island and northern South Island today (Tuesday), and will continue into the evening in most places.

These thunderstorms are accompanied by localised heavy rain or downpours.

In the North Island, from western parts of Auckland and Coromandel Peninsula down to Wairarapa, including the Kaimai and Mamaku ranges and the inland ranges of Gisborne and Hawkes Bay, many of these thunderstorms are expected to be severe, especially inland and particularly about the central North Island, where rainfall rates of 20 to 40 mm/hr (or even 50+ mm/hr) are likely.

Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.

Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.

The thunderstorm activity should ease in Auckland by 5 or 6pm, and elsewhere by 10pm this evening.

Note: A Severe Thunderstorm Watch means conditions are favourable for severe thunderstorms in and close to the watch area. People in these areas should be on the lookout for threatening weather conditions and monitor for possible Severe Thunderstorm Warnings.

For information on preparing for and keeping safe during a storm, see the Civil Defence Get Ready Get Thru website

Issued by: John Crouch

This watch will be updated by: 10:00 pm Tuesday 02 January 2018

[spwill]

I like Auckland this afternoon for storm watching because we are in the fine weather, Waikato looks like a showery mess. Watching south Auckland currently for a possible storm.

[RODALCO]

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Thundercloud is slowly moving towards the Manukau Harbour. Waiatarua may get some action. Clearing in the distance already looking NW.

[NZstorm]

I like Auckland this afternoon for storm watching because we are in the fine weather, Waikato looks like a showery mess. Watching south Auckland currently for a possible storm.

27C out at the airport now.

[jamie]

Thunder non stop since my last post. All IC thunder. Haven’t heard a decent crack yet. Over 10mm so far which is well over due.

[Richard]

Looks to be going off all over the North Island looking by the satellite. Nothing really much is happening down this way.

[Tornado Tim]

Yea quite a bit of Thunder going on, got a indirect hit from a passing storm, which dumped around 20mm, which is very welcome

[TonyT]

Looks to be going off all over the North Island looking by the satellite. Nothing really much is happening down this way.

Thursday is the South Island's big day.

[Richard]

Looks to be going off all over the North Island looking by the satellite. Nothing really much is happening down this way.

Thursday is the South Island's big day.

Thats what i like to hear

[Thunder081]

4:28pm looking NE from Levin

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[NZ Thunderstorm Soc]

Nothing really much is happening down this way.

Same here but humid with that hazy scattered low stratus.
Some weak instabilty inland but nothing to 'wet your pants over'

[Richard]

After an afternoon of promising but weak cb's one has managed to kick it in the guts. Second photo 10 mins later

[Richard]

Another one lurking behind the lower cloud, looking NW

[spwill]

Clouds have been blowing up over southern parts of South Auckland, drove down to Ramarama, very heavy showers down there.

[Richard]

A very photogenic storm in the normal area. Molesworth

[jamie]

Nice one Richard.

Only now seeing blue sky for the first time today. So finally getting a look at the upper portions of the cbs.

[NZstorm]

Nice one Richard.

Only now seeing blue sky for the first time today. So finally getting a look at the upper portions of the cbs.

Yes, too much convection firing over the inland North Island today. A rainy mess. Nice pic Richard.

[dogmelon]

What is it about the Molesworth area that makes it frequently stormy in these boil up type setups?

[NZ Thunderstorm Soc]

Nice picture there, Richard.
I did notice that it did develop some pregnancy and it did fire up.
Yes, it does seem to develop quite often in that area, recently, just like the odd thundery burst we got down here last month, although judging by your photos of the storms around the inland Kaikoura area tend to be rather huge and can be seen from Wellington.
Might be interesting there on Thursday

[Cyclone Tracy]

With the low now over Australian waters and showing signs of initial circulation, it's interesting to see what the higher resolution local models are now producing on run 020117 12z for the arrival of the sub tropical storm. BoM's Access R is projecting an atmospheric river running over 50mm Precip water, a bombing mid 970's hPa surface low with an attacking 110 to 130 km/h gusting north easterly into Auckland. That might require a warning or 2 if it keeps lining up like that in the next 24 hours.

[tgsnoopy]

Last nights update for this afternoon...

http://www.metservice.com/warnings/thunderstorm-outlook

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Thunderstorm Outlook

Valid to: Midnight Wednesday 3 Jan 2018

Issued at: 9:17pm Tuesday 2 Jan 2018

Chart reviewed at 9:15pm Tuesday and no changes made.

A warm humid northerly flow will continue across New Zealand during the second half of Wednesday, which combined with daytime cloud buildups will bring scattered heavy showers or thunderstorms to many parts of New Zealand.

During Wednesday afternoon and evening, the main risk areas for thunderstorms include eastern Bay of Plenty and Gisborne (with the threat continuing into the night), western North Island areas from Waitomo to northern Manawatu (including the central high country), northern South Island areas from Nelson and Marlborough to North Canterbury, and southern South Island areas from eastern Otago to inland Southland. A low risk of thunderstorms covers many other parts of the country as indicated on the chart.

Any thunderstorms that develop will be slow-moving and have the potential to produce localised heavy rain or downpours. Rainfall rates of 10-25mm/hr can be expected, but higher rainfall rates (possibly up to 40mm/hr) are also possible,especially about the western and central North Island from Waitomo to northern Manawatu.

Rainfall rates of this intensity can cause surface and/or flash flooding, and make driving conditions extremely hazardous.

[tgsnoopy]

Also (Just for the record, as per yesterday afternoon).

http://www.metservice.com/warnings/seve ... er-outlook

Severe Weather Outlook

Issued: 2:56pm Tuesday 2 Jan 2018
Valid from Thursday 4 January 2018 to Sunday 7 January 2018

The northeast flow over northern New Zealand strengthens on Thursday as a rapidly deepening low moves towards the west of the North Island from the North Tasman Sea. The deep low is expected to move southeast across central New Zealand during Friday and early Saturday, bringing periods of rain and strong winds to northern and central New Zealand. It should then move southeast away from the country on Saturday, followed by southwesterly flow.

There is moderate confidence that rainfall accumulations will reach warning criteria about Northland and Auckland on Thursday. There is high confidence of rainfall amounts reaching warning amounts late Thursday and Friday for Coromandel Peninsula and Bay of Plenty and the western ranges of Gisborne, but the confidence should reduce to moderate for the area from Waikato to northern Taranaki across to Taupo during the same period.

There is moderate confidence of rainfall accumulation reaching warning amounts from southern Taranaki, Taihape to Wellington, including coastal Marlborough on Friday and early Saturday, but the confidence reduces to low for Wairarapa, Hawkes Bay and coastal Gisborne during the same period. Thers is also moderate confidence of heavy rain for western ranges of Nelson on Friday.

In addition, there is moderate confidence of severe gales across the northern half of the North Island from North Taranaki across to Taupo and northern Gisborne northwards during Thursday and Friday, and for the remainder of the North Island on Friday. There is also moderate confidence that strong southwesterly winds will reach severe gale strength in exposed parts of Banks Peninsula, coastal Marlborough, Wellington and Wairarapa on Saturday.

This significant weather system has the potential to bring severe weather to northern and central New Zealand. People are advised to keep up to date with MetService forecasts and severe weather information.

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