General August Weather

jamie · Unread post by **jamie** » Tue 11/08/2015 07:10

Looks a good frost here. Station is in the shop getting some r and m done so I'm throwing a guess to say it's colder than -2.

SnwAddct · Unread post by **SnwAddct** » Tue 11/08/2015 08:10

Wow what an afternoon we had yesterday! Huge amount of thunder and lightning and about 5cm of graupel settled. Crazy for Auckland

RWood · Unread post by **RWood** » Tue 11/08/2015 08:51

Horrible SE/SSE-er for the 4th day in a row coming up. My most loathed mode in the local climate. Makes the brisk SW/SSW of June & July very pleasant by comparison. The SE/SSE has a bone-chilling quality which makes it feel colder than the other mode, and can drag on for days - the SW/SSW does not hang around long and is normally quickly followed by bright sunshine.

spwill · Unread post by **spwill** » Tue 11/08/2015 16:47

I left a 2 litre bottle of water on the back seat of the car in Arrowtown overnight last night , it was near frozen solid this morning, Central Otago can put on a good frost.

NZstorm · Unread post by **NZstorm** » Tue 11/08/2015 20:12

SnwAddct wrote:Wow what an afternoon we had yesterday! Huge amount of thunder and lightning and about 5cm of graupel settled. Crazy for Auckland

Yes, it was interesting as the day overperformed. Another pic here of the developing convergence line over Auckland taken from the west coast at Murawai.
The line stretched north and south down to the Waikato.

The pic quality is not great as I dropped my phone and the camera has never been right since.

NZstorm · Unread post by **NZstorm** » Tue 11/08/2015 20:39

Manukau heads obs wrote:have seen pictures of the snow pellets on peoples windscreens in west auckland last evening...looks very much like sleet/snow...put you can see little chunks of ice instead of crystals...so its snow pellets (groupel)

Last time we saw snow pellets in Auckland was about 4 years ago.

spwill · Unread post by **spwill** » Wed 12/08/2015 11:13

More cold upper level air heading our way for the weekend, could be some unstable skies Sat/Sun.

Bradley · Unread post by **Bradley** » Wed 12/08/2015 18:04

ACCESS/GFS hinting at a warm advection snow event for this Saturday/Sunday for north Otago/Canterbury above around 200m asl...

snowykiwi · Unread post by **snowykiwi** » Wed 12/08/2015 18:39

will be interesting to see how the model runs keep going. I see metservice are showing snowy weather for Methven for Wednesday, Thursday and Friday next week.

matttbs · Unread post by **matttbs** » Wed 12/08/2015 19:50

Bradley wrote:ACCESS/GFS hinting at a warm advection snow event for this Saturday/Sunday for north Otago/Canterbury above around 200m asl...

I don't see it? The 850mb temp is only -2 at best. Sure the high country may get something but definatly not down to 200m?

Bradley · Unread post by **Bradley** » Wed 12/08/2015 20:14

GFS only had the 850hpa temp at -2C for June's event Matt, also ACCESS has it more like -4C, if that stays then the snow line could get as low as 200-300m...

matttbs · Unread post by **matttbs** » Wed 12/08/2015 20:31

Bradley wrote:GFS only had the 850hpa temp at -2C for June's event Matt, also ACCESS has it more like -4C, if that stays then the snow line could get as low as 200-300m...

I thought it was more like -4 in June but if that's the case it's could be another very busy few days.. The last lot hasn't even melted yet!

jamie · Unread post by **jamie** » Wed 12/08/2015 20:58

Anyone got any idea what snow levels on Sunday could be in central North Island?

Bradley · Unread post by **Bradley** » Wed 12/08/2015 21:31

matttbs wrote:
Bradley wrote:GFS only had the 850hpa temp at -2C for June's event Matt, also ACCESS has it more like -4C, if that stays then the snow line could get as low as 200-300m...
I thought it was more like -4 in June but if that's the case it's could be another very busy few days.. The last lot hasn't even melted yet!

This event is a little more erratic in the models so it may not result in low level snow in the finish but the possibility is there so I'll be keeping an eye on the models the next 24-36 hours for sure!

SnwAddct · Unread post by **SnwAddct** » Wed 12/08/2015 22:25

jamie wrote:Anyone got any idea what snow levels on Sunday could be in central North Island?

I would say around 1600m looking at various models..

NZstorm · Unread post by **NZstorm** » Thu 13/08/2015 07:15

Looking like a thunder/hail risk Fri to Sun for western and upper North Island. Cold upper air creates the instabilty with a couple of strong 500mb vortex to cross the region.

Gfs 500mb chart for later Friday.

spwill · Unread post by **spwill** » Thu 13/08/2015 08:19

Does look like there will be atleast isolated thunder and hail for parts of the upper NI Sat/Sun.
Less the graupel this time

, the low level air is looking warmer than it was on Monday.

Bradley · Unread post by **Bradley** » Thu 13/08/2015 11:13

GFS really liking the idea of 2 wet/snowy events over the next week or so for Canterbury

spwill · Unread post by **spwill** » Fri 14/08/2015 07:47

This webcam at Piha ( West Auckland) http://www.takeabreak.co.nz/accommodation/piha.asp will be useful for observing weather, excellent webcams at http://www.takeabreak.co.nz

Nev · Unread post by **Nev** » Fri 14/08/2015 09:15

Here's this morns T-storm Outlook update for today, with the emphasis more on strong winds and possibly the odd tornado…

MetService - Thunderstorm Outlook

Valid to: Midnight Friday 14 Aug 2015
Issued at: 8:56am Friday 14 Aug 2015

A front crossing Northland this morning is expected to move southwards over Auckland this afternoon and lie over the eastern Bay of Plenty and central North Island on tonight. A band of rain and strong northeasterly winds accompany the front.

As the front moves southwards over Northland this morning and Auckland and northern Waikato this afternoon, the risk of thunderstorms is generally considered low, however the combination of convective cells embedded within the rainband and the the strong northeasterly winds are likely to produce localised wind squalls of 90-120km/hr (or possibly stronger in a few places), as well as short periods of very heavy rain. One or two small tornadoes are also possible.

Winds of this strength can cause damage to vegetation and insecure structures etc, as well as make driving conditions hazardous. A Severe Weather Watch is now in force for Auckland.

As the front moves further south, the risk of thunderstorms increases to moderate over southern Coromandel Peninsula and Bay of Plenty in the evening,along with a continuing risk of heavy rain, strong wind gusts and possibly one or two small tornadoes.

Behind the front, there is a moderate risk of a few thunderstorms developing over Northland in the afternoon, and then further thunderstorms spreading off the Tasman Sea into Northland and Auckland at night. These thunderstorms are likely to contain small hail.

A lower risk of thunderstorms cover the central North Island and western Nelson from evening as indicated on the chart.

No other thunderstorms or significant convection expected elsewhere.

MetService T-storm Outlook Map for Aug 14.png

Tornado Tim · Unread post by **Tornado Tim** » Fri 14/08/2015 10:41

I see there could be a fohn wind for the Waikato and Parts of the BOP, on Sunday, will be interesting.

Liking the risk of a storm and squall today. The narrow upper level jet streaming down towards Taranaki and Westland this afternoon will play a good part in how vigorous the event will be today.

Heavy Showers a risk on Saturday, might turn Thundery with the risk of Hail. - Less organised than Today due to the trough being much more broad and the jet extending from Auckland northwards.

The Residual Moisture and mild SFC temps should help with any convection that occurs though.

Manukau heads obs · Fri 14/08/2015 12:02

torrential rain here

Manukau heads obs · Fri 14/08/2015 13:27

17mm here in 2 heavy bursts

jamie · Unread post by **jamie** » Fri 14/08/2015 13:45

Gutted I haven't got the station back from weather data yet. Will miss this event except for wind speeds.

I'm at Taupo currently and the wind is starting to pick up here.

littleheaven · Unread post by **littleheaven** » Fri 14/08/2015 16:30

Very benign here in Takapuna, after a very blustery wet morning. Patches of blue sky to the East, a bit murky to the West. After this morning's headlines about weather bombs (lol) and battering thunderstorms, it's amusingly quiet.

NZ Weather Forum