General December Weather

[03Stormchaser]

Tomorrow should be another day around 30c, Tuesday - Thursday be around 20C and then back into the warmer weather from Friday again. Rain also in the forcast, won't be enough but we'll take anything, just over a month of no rain here. So looking like only a short respite from the warmth.

[melja]

SW change on just arrived here, still 29C and a beautiful evening. I see new Brighton is only 19C with a 33kph NE.

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[NZ Thunderstorm Soc]

. Rain also in the forcast, won't be enough but we'll take anything, just over a month of no rain here..

MS saying on their blog if it dosen't rain before 9am, tomorrow morning, a new dryness period record looks likely for ChCh.

[spwill]

See if we can score a shower for my garden today with the afternoon convergence over Auckland, the best chance for a shower will be over the hill country to the north and south. Tomorrow afternoon the convergence looks a little further east.

[jamie]

Desperate for rain here. We missed all the thunderstorms. No proper rain for 26 days now which we had 26mm. Since then we have had 1's and a 2mm (totaling 6mm) which do nothing.

Never do I remember the ground going from saturated to grass browning off in 4 weeks. Getting very brown quickly now.

[Chris W]

Metservice just tweeted that the dry spell is now the longest in 74 years for Christchurch, with 46 days of less than 1mm rainfall. The '1.2mm' day for me was just out at the airport, out at New Brighton we've had nothing for weeks.

[Razor]

Metservice just tweeted that the dry spell is now the longest in 74 years for Christchurch, with 46 days of less than 1mm rainfall. The '1.2mm' day for me was just out at the airport, out at New Brighton we've had nothing for weeks.

This is easy for us- in Halswell it hasn't rained for at least 53 days, because that's when we moved in and we haven't had measurable rain since then. So its that plus a few more

[spwill]

Desperate for rain here. We missed all the thunderstorms. No proper rain for 26 days now which we had 26mm. Since then we have had 1's and a 2mm (totaling 6mm) which do nothing.

Never do I remember the ground going from saturated to grass browning off in 4 weeks. Getting very brown quickly now.

It is looking like a mainly fine sunny week coming up for our region , Northland and the Kaimais have the best chance for a shower next couple of days.

[Cyclone Tracy]

The incredible surge south from the Hadley cell 4 weeks ago has the created the super ridge and its now becoming more clear the consequences for NZ. Eventually the ocean heat bubble will explode but how and when is up for debate. The monsoon trough and walker cell has pushed north of the equator again, so it seems unlikely its an ex TC cyclone in the next 4 weeks. Maybe an upper low can spawn a localised cold core cyclonic gyre in a week or so but this ridge has been bullet proof so far.

IMO, based on water temperature increases from the last 5 weeks to around 21c to 24c off the upper NI, a sizable warm core tropical cyclone could be sustained in late January, early February around the upper NI. This would transition to a powerful extra tropical cyclonic impact on the south island depending on steering and shear. Every day, these oceans temps are becoming more interesting. Time will tell

[Razor]

Just snuck past 30 degrees for the 4th straight day out our way, but I don't think the 'official' temp at the airport has quite made it (yet)

[TonyT]

The incredible surge south from the Hadley cell 4 weeks ago has the created the super ridge and its now becoming more clear the consequences for NZ. Eventually the ocean heat bubble will explode but how and when is up for debate. The monsoon trough and walker cell has pushed north of the equator again, so it seems unlikely its an ex TC cyclone in the next 4 weeks. Maybe an upper low can spawn a localised cold core cyclonic gyre in a week or so but this ridge has been bullet proof so far.

IMO, based on water temperature increases from the last 5 weeks to around 21c to 24c off the upper NI, a sizable warm core tropical cyclone could be sustained in late January, early February around the upper NI. This would transition to a powerful extra tropical cyclonic impact on the south island depending on steering and shear. Every day, these oceans temps are becoming more interesting. Time will tell

You are 100% right Mr Tracy, normally we would be seeing the Tasman Sea a spawning ground for low pressure systems of all shapes an sizes with these SSTs. What we have been seeing is unusual, and a return to normal is bound to come eventually with a significant correction to rainfall totals.

[melja]

The way I see it, well for chch anyway is that we had our annual rainfall months ago so it was bound to get dry at some point to even it out.
Not bad 6 days out of the first 11 of the month hitting 30 here and 8 days topping 28.

[NZstorm]

Just snuck past 30 degrees for the 4th straight day out our way, but I don't think the 'official' temp at the airport has quite made it (yet)

Airport got up to 28C on the metars. Looks unlikely to have got the 30C.

The airports tend to be good locations for weather readings as there is plenty of open space. Temperature recorders need to be over mowed grass and away from buildings.

Blenheim Woodburn got to atleast 31C today. Auckland Ardmore was the warmest of the Auckland airports on 27C.

[03Stormchaser]

Where abouts is this 46 days of no rain in Christchurch record from? I thought we had more than a 1mm on Nov 8th

[melja]

Gardens I think

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[NZ Thunderstorm Soc]

The airports tend to be good locations for weather readings as there is plenty of open space. Temperature recorders need to be over mowed grass and away from buildings.

.

I tend to agree with this.
Temperatures I record here in Geraldine seem to be of an urban base whereas when we were in West Melton, the readings I got from my old defunct Stevenson's Screen were a long way out from any buildings, etc. and probably recorded a more accurate temperature of the atmosphere.

[Richard]

Thats why Hanmer Spring's temps should not be recognised because of buildings and pavements close by, mind you was it deliberately put in such a location so as to give the town promotion.?

Mowed or long grass, does that make any difference?, NIWA's CWS in my paddock at the moment has longish dry grass all around it

[einzack]

Up to 4.7mm of lovely rain so far today. Could definitely do with a bunch more, and we might just get a wee bit.
First >0.5mm fall since November 8th, so like everyone else, very dry.

[NZ Thunderstorm Soc]

Cool southerly moving through here at the moment.
I wonder if we will get any rain out of it?

[Orion]

Southerly just arriving here

[TonyT]

Interestingly the Total Solar Irriadiance (TSI) has dropped significantly in the last few days. The difference from normal is only slight, but I have been watching these readings and there does seem to be a reaction of surface temperature with the more significant spikes downwards.

The last time it did that (and to similar levels) was at the very end of September and the first week of October, when we saw significant low pressure systems affecting New Zealand and some unseasonably cold temperatures with snow on the North Island ranges. Obviously the current warmth in the Tasman Sea will mitigate against a repeat of that this time, but be alert for temperatures this week to be perhaps a little colder than the models predict, and that you might think for the type of system. This will likely be a global effect for a week or so, so more snow and cold in the Northern Hemisphere is likely.

http://lasp.colorado.edu/data/sorce/tot ... 40x480.png

[NZ Thunderstorm Soc]

Yes it is interesting to hear about the cold snowy weather in the eastern USA and in Britain and even reports of snow to high levels in Hawaii.
......so why is California burning?

[TonyT]

Yes it is interesting to hear about the cold snowy weather in the eastern USA and in Britain and even reports of snow to high levels in Hawaii.
......so why is California burning?

Fuel buildup from the very wet summer followed by autumn dryness. Lots of dead grass around to burn. Plus its a typical La Nina USA pattern to be cold in the east and warm in the west. Probably not such a good snow season in the Rockies, pretty epic in the Appalachians.

[einzack]

Ended up with 28mm here. Was lovely hearing rain on the roof again, some very heavy at times. The farmers will be happy! As will my lawn.

[NZstorm]

Weather looking OK for the festive period with a ridge building in. Max temps under 25C on Christmas day but above 25C in many places Boxing day.

There is a pre Christmas cool spell 18th to 20th which could feel very cool up the east coast.