General August Weather

[jamie]

Stunning day today. Very warm. Our grass growth on farm this past 4 weeks has been phenomenal. Plenty of people making silage and it’s first week August.


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[Awhituobs]

the key will be that the soil temperature has been higher than normal (I am on 12.5c here )

[Richard]

10cm soil temp is at 8.5 deg here as of now. Nice day with a NW wind and a max of 17.4deg.

[David]

Yep, a beautiful Spring-like day, went up to Mangawhai and did the coastal walkway - amazing views. Wore a t-shirt most of the way.

[cbm]

I can walk, even use a ladder anywhere on the lawn at the moment and it does not sink in which is great now but a bit scary. Lets hope it's a different summer to the last two, with regular rain events.

[NZ Thunderstorm Soc]

Another day of extensive high cloud but much thinner and sometimes, lumpier than the previous days with some mammatus and lenticular forms in the cloud, extending out from the west.
Not much wind again, if so, light and variant.
Today's maximum was 15.4C.

[tornado]

Some fog across auckland clearing away now to a sunny day. some rain end of week. perhaps thunder but i doubt it.

[Bradley]

MJO is currently in phase 4 which is the anticyclonic phase for NZ, but the blocking H to the east and the north to northeast airflow we are stuck under is more phase 5. If the flow is going to go well southwest in the near future then we need the MJO to push back towards phases 2&3. Currently only the JMA wants to bring that on, the rest can't make up their minds. Just how cold and how long lasting this next cold shot is will depend on where the MJO settles to.

Some very interesting divergence's in the forecasts from EC and GFS for next Tuesday - EC not keen on any severe coldsnaps at all with only -4C at 850hpa forecast for Tuesday for Canterbury whereas GFS paints a very different picture indeed with a consistent forecast of 850hpa temps of -8C on Tuesday with near sea level snow. Based on the last few months I am favouring the reality to be more like the GFS forecast. Tony are you seeing anything around which might point to which model may be more accurate?

[snow101]

MJO is currently in phase 4 which is the anticyclonic phase for NZ, but the blocking H to the east and the north to northeast airflow we are stuck under is more phase 5. If the flow is going to go well southwest in the near future then we need the MJO to push back towards phases 2&3. Currently only the JMA wants to bring that on, the rest can't make up their minds. Just how cold and how long lasting this next cold shot is will depend on where the MJO settles to.

Some very interesting divergence's in the forecasts from EC and GFS for next Tuesday - EC not keen on any severe coldsnaps at all with only -4C at 850hpa forecast for Tuesday for Canterbury whereas GFS paints a very different picture indeed with a consistent forecast of 850hpa temps of -8C on Tuesday with near sea level snow. Based on the last few months I am favouring the reality to be more like the GFS forecast. Tony are you seeing anything around which might point to which model may be more accurate?

Its quite hard to get a clear picture about where things are going to next week. I've been watching the gfs ensembles which have been pretty consistent about the event from the beginning, where as EC (and its ensemble) has been in and out. Interesting few days ahead for sure.

[TonyT]

Tony are you seeing anything around which might point to which model may be more accurate?

No, Its a head scratcher. Basically the MJO is not playing ball with cold SW, so there are background influences gnawing away at that idea.

[spwill]

The northern low early next week would be interesting for snow if it tracked further south but it looks likely will cross northern NZ area.

Snow fell to sea level for parts of Tasmania yesterday and reports of sleet for coastal Victoria and snow to low levels on the hills inland

[Bradley]

Tony are you seeing anything around which might point to which model may be more accurate?

No, Its a head scratcher. Basically the MJO is not playing ball with cold SW, so there are background influences gnawing away at that idea.

Thnaks Tony, does the MJO always have to be in the favourable phase to get a severe cold snap? Like the one's in July and August 2011? Or is it possible without the MJO playing ball?

[Razor]

Surprised to see this freezing southerly change sneak into ChCh today. Wasn't expecting that!

[Razor]

Tony are you seeing anything around which might point to which model may be more accurate?

No, Its a head scratcher. Basically the MJO is not playing ball with cold SW, so there are background influences gnawing away at that idea.

At this stage Metservice is pumping for a fine week next week, for ChCh anyway.

[Cantab03]

The latest run on the GFS has pulled back quite a bit on the projected wintry blast. I definitely feel the EC is a far better model several days out compared to the GFS. Thing we will start seeing GFS coming into alignment more and more now with EC moving forward. Pity, would have been good to get one decent snowstorm this winter, very starved of late!

[spwill]

Some fog across auckland clearing away now to a sunny day. some rain end of week. perhaps thunder but i doubt it.

Friday through to Saturday morning showing thunder risk here as the main rain/shower features come through.

[TonyT]

Thnaks Tony, does the MJO always have to be in the favourable phase to get a severe cold snap? Like the one's in July and August 2011? Or is it possible without the MJO playing ball?

To get a severe cold snap, probably yes. To get a cold snap, probably not. Its the salt which enhances the flavour, not the flavour itself.

[David]

Just 4.6mm here over the last 14 days. Very strange to see the ground this dry in August.

[NZ Thunderstorm Soc]

A partly cloudy day with the odd sunshine and weak looking Cu humulus cloud forms dotted across the plains.
Today's maximum was 15C.
Low cloud this evening.

[Chris W]

Plenty model variability going on for Monday and we’re still 5 days out, lots to play for especially with the jet interaction.

Before that, Friday might be a chilly awakening after the recent warmer spell. Uppers aren’t as cold as they were being modelled but it’s still a cold change. MetService going for snow to 6-700m on Saturday.

[NZstorm]

Certainly a chance of thunder for Auckland region with that cold upper level system crossing. Front early morning and another front Friday afternoon. UKmet has up to 30mm for Auckland tomorrow but EU and GFS less.

[Cyclone Tracy]

Twin sister vortex's coupled between Stratopshere and Tropopshere over the Antarctic continent today. SAM (AAO) index falling off the cliff in the next 7 days on GEFS ensemble.

The Polar Jet will probably displace equatorward in the next 10 days. Models will be become volatile soon with relation to cold outbreaks and polar streamers. Seems to be show time coming soon.

[Awhituobs]

I see that the low crossing central Australia is bringing good rain to South Australia, will see them up nicely for spring crops etc

[tornado]

yes thunder chance tommorow. august can be a wet and thundery month but this august might be drier. and less thundery. i really hope tommorow produces thunder and lightning. metservice has a mod risk for us tonight. totally changed from yesterdays outlook for today.

[mikestormchaser]

Thnaks Tony, does the MJO always have to be in the favourable phase to get a severe cold snap? Like the one's in July and August 2011? Or is it possible without the MJO playing ball?

Its the salt which enhances the flavour, not the flavour itself.

Thats a very good simple way of putting it.