General December Weather

[Bradley]

Wow!

If this comes off then we are sure in for an interesting summer. Get the umbrellas ready and the storm chasing vehicles fuelled up. And popcorn, must have popcorn handy.

[This is the latest ECMWF prediction of 500mb height anomalies for the December to February period. The intense blue colour over NZ shows significantly lower than normal predicted heights (equivalent to lower surface pressure and/or cold). It also suggests easterly anomalies, with higher than usual heights/pressure in the southern Pacific.]

Excuse my ignorance but if it does mean cold anamolies as well as lower pressure wouldn’t that take away the heat/fuel for more storms, seems to be counter intuitive?

[TonyT]

Wow!

If this comes off then we are sure in for an interesting summer. Get the umbrellas ready and the storm chasing vehicles fuelled up. And popcorn, must have popcorn handy.

[This is the latest ECMWF prediction of 500mb height anomalies for the December to February period. The intense blue colour over NZ shows significantly lower than normal predicted heights (equivalent to lower surface pressure and/or cold). It also suggests easterly anomalies, with higher than usual heights/pressure in the southern Pacific.]

Excuse my ignorance but if it does mean cold anamolies as well as lower pressure wouldn’t that take away the heat/fuel for more storms, seems to be counter intuitive?

Colder air generally produces better convection, hence why we often get our best thunderstorms in southwest wind flows or on the leading edge of cold fronts.

[RODALCO]

Took a couple of pics on my evening walk. Some nice Cumulus around. First is looking east towards Beachlands area at 7:30pm, second is looking north at 8pm.

The second one is the one I saw also from Takapuna.

[Richard]

Was this S wind change and now a cloudy morning forecast?, today's forecast doesn't say anything about early morning cloud clearly

[NZstorm]

Models indicating some thunder next week over the North Island. EU has an upper trough mid to late week.

[shovelopikis]

We drove through taihape two days ago and hit the biggest hailstorm ive ever seen in NZ, around pea to marble size and lay on the ground and road all afternoon. .

[Nev]

We drove through taihape two days ago and hit the biggest hailstorm ive ever seen in NZ, around pea to marble size and lay on the ground and road all afternoon. .

A few good pics in the media.
https://www.nzherald.co.nz/nz/news/arti ... d=12172469

https://www.stuff.co.nz/national/109150 ... in-streets

P.S. Probably should be in the T-storms thread…

[Dean.]

A warm muggy night here 21 with a dewpoint of 16 at 7.30

[NZ Thunderstorm Soc]

Same here with increasing high cloud.
DP of 10.5C
Nice to have our evening repast outdoors

[Richard]

A very summery day with a 28deg max, a light NW wind sprung up mid afternoon

[NZ Thunderstorm Soc]

Warm and muggy here too especially when the sun came out when we were at the Plains Railway in Tinwald.

[Dean.]

Warm and muggy here too especially when the sun came out when we were at the Plains Railway in Tinwald.

Was very warm and muggy in the high country today too...overcast 24 today DP's 17...winter in the tropics

[Cyclone Tracy]

Something to ponder and keep an eye on for NZ off todays 0912 00z runs for EC and UK.

[cbm]

Warm over in the Rotorua area today. Car was reading as high as 29C due to near solstice sun heating the road surface. Lake Okataina was very high, It has no outlet so follows long term rainfall trends. Lakeside signs were underwater. About 6-8m high Manuka in places on lake edge is dying from being submerged.
Saw a high of 26.8C in Cambridge, was fairly sheltered in this flow also.

[NZstorm]

That was a warm airmass over the North Island at the weekend but the southwesterly kept temperatures down in the west. Managed to get 23C in Grey Lynn on both days though.

Looking like lighter winds from tomorrow afternoon with convection increasing this week over the country. Thunder about the central North Island ranges tomorrow afternoon.

[spwill]

A mostly sunny weekend here but the wind was a real spoiler.

[Tornado Tim]

Yes, looking quite convective from tomorrow onwards..... quite an interesting pattern emerging.....

[NZ Thunderstorm Soc]

After yesterday's humid weather and warm temperatures, looks like the 'clagg' has returned today and looks likely to hang around all week.

[cbm]

Very savanna like tonight. Warm and still with storms in the distance.

Sent from my SM-N950F using Tapatalk

[Simon Culling]

According to this NIWA tweet, Rotorua recorded its highest ever December temperature (28.4*C) on Sunday the 9th, although I am not aware of the length of the record.

https://twitter.com/NiwaWeather/status/ ... 6963212288

[Richard]

One colour grey low cloud this morning, within the storm low risk and close to the moderate area here this afternoon, its normally favourable for development later in the day when its gloomy first thing, but that's whats unusual about last weeks small storm which developed close by,it started off grey like this, very unusual for here.

[Tornado Tim]

Very hazy out here atm... Upper temps are a little warmer than the last few setups today so that could impact chances of getting a decent storm.

[spwill]

A sunny start here, afternoon convergence will bring a low end shower chance here. Tomorrow looks better for an afternoon shower chance over the Auckland region, more likely over eastern parts with isolated thunder risk.

Keeping a watch on the rest of the week for afternoon showers/thunder. Friday could be an interesting day.

[Cyclone Tracy]

EC 1012 12Z now projecting the cut off low scenario into it's medium range with an upper low attack on a very strong ridge. Plenty can change of course but fascinating to watch this unfold from 2 weeks ago with Rossby waves propagating into the lower stratosphere, moving the Polar Jet equatorward.

[Nev]

According to this NIWA tweet, Rotorua recorded its highest ever December temperature (28.4*C) on Sunday the 9th, although I am not aware of the length of the record.

https://twitter.com/NiwaWeather/status/ ... 6963212288

Think you mean 28.4C on Monday 10th and 28.0C on Sunday 9th.

That Rotorua site, around the town's Arawa Park Racecourse, is just over 3-years-old. So not hard to beat its own record of 28.3C on Dec 28, 2015. However, NIWA also said that records go back to 1972, so I assume they're including the airport, even though records began there in 1963, with 29.5C recorded in Dec 1969. There was also an earlier (aero?) site just south of the town, which has recorded a few higher Dec temps between 1921 and 1956, the highest being 31.1C in 1948.