General August Weather

[Bradley]

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.

It's a pity the MJO isn't playing ball in the next 10 days and also high pressure systems will be in the wrong spot blocking the worst of any cold outbreaks that are coming up in the next 7-10 days because that is a truly spectacular forecast for the SAM over the next few weeks, it could have been something special if it wasn't for those 2 factors!

[Chris W]

Still might be, don't want to underplay the MJO not least as my understanding of it is limited but the polar vortex is getting very involved courtesy of stratospheric factors with that ozone/warm area from June (see the strat thread). When you throw a Tasman low in there's good potential even without the holy grail of a perfect storm of straight roaring southerlies, -10 850s and a supercharged subtropical dipping jet, IMO.

[Cyclone Tracy]

A cell is currently lightning active 200km NW of Auckland over the Tasman. Cloud tops near -60c.

[NZ Thunderstorm Soc]

A cell is currently lightning active 200km NW of Auckland over the Tasman. Cloud tops near -60c.

Yes. Watching it on the Blitz. Would be nice to see this activity down this way?
tornado, i hope you are keeping an eye on this ?

[Awhituobs]

nice looking blob ..I might get this here

[NZ Thunderstorm Soc]

A rather cold day here with a mixture of low cloud or fog and high cloud layers when the low cloud parted.
Today's maximum being only 9.4C.

[Awhituobs]

great barrier island getting a thunderstorm currently
we got some needed rain at least, 17mm

[Awhituobs]

a polar high in the southern ocean is showing up in the models for in a week and there will be very cold air shoveled north because of it..but some models have that missing the south island to the east?

[David]

Almost 16mm here overnight. Mostly fell in 30 minutes near midnight. Was woken by a clap of thunder at 12.10am, but didn't hear any further activity.

[NZstorm]

6mm here overnight.

A shortwave trough due this afternoon and another one tomorrow morning.

[Richard]

A rather cold day here with a mixture of low cloud or fog and high cloud layers when the low cloud parted.
Today's maximum being only 9.4C.

Wouldn't have thought yesterday that this top end of Canterbury was so different to your area John, managed 17 deg here.

[Awhituobs]

lightning active CB just passing to my west

[Nev]

Almost 16mm here overnight. Mostly fell in 30 minutes near midnight. Was woken by a clap of thunder at 12.10am, but didn't hear any further activity.

32mm here overnight, most of which fell in the hour to about 1:30am, along with a few strikes in and around the island not long after 1am.

[Cyclone Tracy]

7mm locally overnight. Currently 14c, a 13c DP with the sun out.

[tornado]

yes woken by a downpour territorial rain at midnight. flash of lightning/clap of thunder too. quite loud rumble too yay. more possible this afternoon. august is a month where we can get a lot of rain/thunder. 23mm overnight i actually think this might be our best thunder set up this year.

[tornado]

A cell is currently lightning active 200km NW of Auckland over the Tasman. Cloud tops near -60c.

Yes. Watching it on the Blitz. Would be nice to see this activity down this way?
tornado, i hope you are keeping an eye on this ?

i was. but i didnt wanna overclogg the forum like i used to do lol.

[Awhituobs]

does look like a good cold blast and snow coming for eastern SI in a week...

[TonyT]

does look like a good cold blast and snow coming for eastern SI in a week...

The MJO will come out of the "anti-SW" phase 4 and into the null phase in the next 3-4 days, so that makes the end of next week event more likely than the last two times cold and snow has been modelled 7 days out (ie targeting today, and next Tuesday) only to fizzle out. Third time lucky perhaps?

[Bradley]

does look like a good cold blast and snow coming for eastern SI in a week...

The MJO will come out of the "anti-SW" phase 4 and into the null phase in the next 3-4 days, so that makes the end of next week event more likely than the last two times cold and snow has been modelled 7 days out (ie targeting today, and next Tuesday) only to fizzle out. Third time lucky perhaps?

Let's hope so though both GFS and EC are both now saying nothing at all severe in terms of SW changes until at least Saturday now (even then only EC is suggesting low level snow for next Saturday, GFS has nothing) this winter is quickly starting to rival 2014 as the most uneventful/boring of the past decade...

[spwill]

Been a nice day here so far, 17C, a shower line to come through this afternoon. Northland has been catching thunder today

[spwill]

At this stage Northland looking well placed for thunder this afternoon, I see a storm has developed on the line west of Auckland.

[tornado]

yes thunderstorm west of auckland. coming in soon. re most of the activity keeps going to northland. i want more than one rumble. when will auckland get a proper storm for once?

[mikestormchaser]

The MJO will come out of the "anti-SW" phase 4 and into the null phase in the next 3-4 days, so that makes the end of next week event more likely than the last two times cold and snow has been modelled 7 days out (ie targeting today, and next Tuesday) only to fizzle out. Third time lucky perhaps?

Let's hope so though both GFS and EC are both now saying nothing at all severe in terms of SW changes until at least Saturday now (even then only EC is suggesting low level snow for next Saturday, GFS has nothing) this winter is quickly starting to rival 2014 as the most uneventful/boring of the past decade...

Next fri/ sat is definitely one to keep watch on. But the event next monday /Tuesday has vanished.

[tornado]

the incoming shower might miss us but we might get the main band. and maybe something thundery could go off when that arrives.

[Awhituobs]

nice thunderstorm through here,hail even, and close strikes in the Waiuku area...edit...reports that the waiuku area had a good thundestorm and torrential rain ...it intensified quickly on the rain radar thats for sure!