Unstable over NI 22nd-27th

[David]

Most models still looking sure of this scenario for cold upper atmosphere, but how come metservice only mention few showers in the outlook for next week?
Are they not expecting anything? That would be disappointing.

[NZstorm]

metservice only mention few showers in the outlook for next week?

Met Service generaly don't put much detail in their long range forecasts.

Looking like the cold pool will cross Northland Monday with a high risk of thunderstorms/hail there. Not sure about Auckland at this stage. Looks like the best of the instability on Monday will roll over the top of us.

[spwill]

Met Service generaly don't put much detail in their long range forecasts.

Blue skies do this much better (at fencePost)

[David]

Blue skies do this much better (at fencePost)

Would like to have a look on there... but the internet is so slow I cannot get anywhere on that site

Very annoyed now, first I tried to open my tipping bucket rain gauge earlier (turn the funnel clockwise) and then the funnel was jammed so I spent two minutes twisting and forcefully trying to turn it, and then it finally came open. The most annoying part was the ten tips recorded

What a way to start the holidays, the weather better offer something good soon.

[David]

Metvuw charts suggesting a depression may move down over the north island from the north next friday, with rain and wind. Bit far out right now so would not be very accurate. The US-7day models on weatherzone also predict similar.

Upper air temps still looking to be cold from Monday

[David]

Auckland meteorogram seems good at the moment.
CAPE looks to rise, as well as lifted index, 500mb temps set to fall, and I don't know what convective inhibition is if anyone can help me there.
Good amount of precipitation there too, 69mm.
Looking good

[David]

Metservice don't seem to be expected much from this. Maybe there is some limiting conditions, i.e one factor preventing much activity from happening. You'd think that if there were going to be some nice thunderstorms Met service would have picked that up. Hopefully I'm wrong, but usually with things like these something limits the atmospheric activity and the potential for what may have happened is often just what it says, a 'potential'.

[David]

I deleted the metvuw image I posted as it dramatically changed and showed an anticyclone instead.
(another reason not to trust forecasts beyond the next 2-3 days)

500mb temps for later this week for Auckland, around -32 for a time

[David]

Warm this morning at 16C right now, but the sky is 8/8 with cloud cover. It is clears we may get some convection occurring.

[NZstorm]

It is clears we may get some convection

Yes, but possibly more cloud cover today.

[David]

From Metservice:

Valid to: 12:00 am 24 Sep 2007 NZST
Issued at: 9:23 am 23 Sep 2007 NZST

A frontal wave is expected to move down over the upper and central North Island through the period destabilising the atmosphere. Some cooling aloft, an injection of low level moisture and daytime heating, combine to give a moderate risk of thunderstorms over southern Northland, Auckland,Coromandel Peninsula Waikato and Waitomo and parts of Taumarunui. These storms could give rainfall rates in the 10-25mm/hr range and some small hail. There is a lower risk of thunderstorms in a wider envelope from central Northland over to eastern Bay of Plenty and as far south as northern Manawatu. The risk in Bay of Plenty comes in the evening and at night.

There is also a low risk of thunderstorms along the South Island west coast from about Hokitika to northwest Nelson.

Elsewhere, no thunderstorms or significant convection is expected.


Great! Was not expecting much activity over the Auckland area today, but it seems the main area of focus has shifted south than from where it was expected to be. Cloud breaking now so we should get some good heating here today. Just as long as the current northeasterly does not pick up any more...

[C-Nimbus]

This grotty cloud will have to burn off first. The heating component would be very important at this time of year one would have thought.

Still tho, metservice increased their risk from low to moderate in the last 24hrs

[spwill]

Nice to wake up to 19C, dewpoints 15C.

Low cloud will burn away like yesterday .

[David]

Must be some low level moisture, saw on my walk that the distant sky tower had the section above the viewing platform hidden behind cloud. Sunshine getting through now and temps warming, but the cumulus around only looks to be the 'humilis' or 'fair weather' type with a few at the mediocris stage at the mo, would have expected some stronger development to have been occuring at this point of the day.

Also moderate risk tomorrow for thunderstorms

And spwill! You only just woke up!

[Cameo1]

Big rain drops falling here Thats a good sign

[David]

Doesn't that mean that the updraught in the cloud is strong enough to enhance coalescence and support larger rain drops?
This also meaning once a cb becomes glaciated that the cloud can allow hail to develop?

[Manukau heads obs]

heavy rain now developing over the waitakere ranges....but moving out into the tasman...but it looks to be back building a bit

[David]

I'd say the clouds have alot more developing to do before they yield heavy rain and thunderstorms around auckland, the one you're referring to Brian must be an isolated one. Spitty rain drops here but skies clouding over now.

Here's the best i've seen, taken at 1.30:

[spwill]

Low cloud has cleared however medium level cloud and some light rain has moved in from the north killing convection for now. This cloud sheet may have moved through by mid afternoon but I think the thunder chances today are now a dead duck.

[David]

How disappointing and typical

[NZstorm]

Looks like we have ended up with persistent rain this afternoon rather than scattered showers. That warm front has become more active as it has drifted south into our area.

[Cameo1]

Whats going on out there guys??? What happened to our thunderstorms ???????

[David]

Whats going on out there guys??? What happened to our thunderstorms ???????

No lightning strikes but a few heavy showers in central northland by the looks of the rain radar. A fizzer today.
Edit at 4.43
I thought I heard thunder but the lightning tracker did not pick up anything so it must have been a plane

[Cameo1]

oh darn I hate it when that happens, though its usually trucks that do it to me lol:D

[David]

I see Brian's station at graham's beach reported 16mm in an hour
Must have slowed and intensified over his area, considering the 5pm radar showed nothing spectacular.
Should be some more shower activity over Auckland later this evening.