General July Weather

[David]

cold heavy rain showers going through the auckland area!
5c here with rain
i.e cold air trapped at the surface with rain showers going over the top of that
we dont get it much colder than that!

Yeah was 4C here when it rained at 2.30am, a little unusual for us

[Awhituobs]

temperature still dropping here (will do until the sun comes up)
as the wind has stopped and the sky is clear
only 2c now in Waiuku

[Bradley]

Thanks Tony thought that isn't like you to talk about events so far out, is there something in the models that is leading you to think that it is a possibility? Negative AAO combined with a favourable phase of the MJO perhaps?

Well I have been quite vague, deliberately!

MJO is spiking into 2 and expected to be declining in 3 by then. So that is supportive of the idea (well lets put it this way, you wouldn't put money on a mild N airflow with that MJO pattern). But really its just something which has been in the longer range modelling for some time (so consistency is a factor) and backed by the posts above - in a time when meridional flow is dominant over zonal and the polar vortex is wobbly (not unusual) then a leak of cold air onto the country is likely, but when?. Those dates just fit with what the longer term modelling is saying.

Ben Noll from NIWA on Breakfast TV this morning saying we should expect ‘warmer then normal’ temperatures for the next 2-3 weeks, he must be seeing something the rest of us aren’t...

[Awhituobs]

but he was talking about after this cold snap
and he is talking averages
this saturday will be warm NW winds over the eastern SI for starters
then sunday a warmer than normal northerly flow
then a cold SW flow
and after that,....you can only talk in very general ideas

[Awhituobs]

I see Jamie went down to -1.2C this morning
so a good frost in the Waikato

[snowykiwi]

32mm of rain overnight here in Rakaia

[Orion]

Please, what is AAO and MJO?

[Awhituobs]

MJO is madian Julian Oscilation
its refers to a back building increase in thunderstorm development that propagates along the inter tropical convergence line, starting in Indonesia
and ending up NE of NZ eventually
and that increase in tropical energy occurs every month or so
and some phases are stronger than others
when it couples with a tropical jet stream that is diving south then NZ is more prone to injections of tropical moisture from the north
it also spawns tropical cyclones too sometimes (in that season)

i think AAO is the antarctic annual oscilation (or also the SAM ...southern anular mode...i.e how far north the westerly belt is )

[spwill]

The chance for a frost tonight for parts of Auckland.

[cbm]

I see Jamie went down to -1.2C this morning
so a good frost in the Waikato

-1.7C at mine. Decent, but given this is early July only a moderate frost for here.

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[cbm]

Unusual for Tauranga to be in single digits this time of day.

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[NZ Thunderstorm Soc]

Some cloud overnight but a mainly fine and cold day, here.
Light winds. Today's maximum was 8.4C.
Frosty this evening, down to minus 1.1C at 10pm.

[spwill]

Clear skies here but a breeze is holding temperatures up , currently 9C.

[Awhituobs]

ohh, 3.1c at Ricky's place currently
(its 9.2 c here with the southerly wind)

[NZstorm]

Ardmore Airport on -1C.

[Awhituobs]

-0.4c in waiuku

[David]

Down to 1.3C here this morning, frozen cars and a light frost.

[spwill]

Light frost here, some white on open grassed areas.


More cold air next week. Some thunder chances next week, it has been a poor thunderstorm season for my area so far.

[tornado]

-1c in takanini this morning. yes another thunderstorm chance next week. had 2 thunderstorms this year in my area. maybe chance of more tornadoes? taranaki perhaps. anyway. winter has fully started for now. frost this morning too.

[cbm]

Some of you got colder than me, only -0.8 this morning.

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[NZ Thunderstorm Soc]

From minus 4.2C this morning around 8am, a lovely fine day eventuated. Not much wind
Thin high cloud moving across from the west from later this afternoon.
Should be a cold NW day tomorrow with the Arch and lack of windflow.

[NZ Thunderstorm Soc]

Some thunderstorms on the West Coast with this incoming system, tonight.

[NZ Thunderstorm Soc]

A basically fine day with some high cloud moving across from the west.
Today's maximum was just 9C.

[Orion]

Technicolor-scarlet clouds before sunrise this morning!

11.9°C at present

[spwill]

Nice to have the mild start to the day , Grey Lynn 14.8C by 9am. Some cold mornings later in the week.