Low 15-17th December

[David]

Don't know what metservice were thinking??? Ended up with a lousy 2.4mm rainfall.

[Manukau heads obs]

the lows/fronts from the tasman have been weakening by the time they reach the NI for a few weeks now...they should have factored that in more...

[David]

Yes not good how we could be heading into January and February already dry - the last several years summer rainfall always seems to end up lower than could be expected.

[Tornado Tim]

A Truly massive CB Calvus is developing to the East just now, It had a Pileus cap for about 1 minute then went.
Might be a thunderstorm soon,good for the people of the East.
Seems to be allot of verticle activity today for the waikato.
Looking North it looks quite good too.
Update:
DP: 14-15 deg reasonable
LI: -2-3 @ 750mb-500mb which means thunderstorms are possible
Something is brewing its hot and moist and all clouds are towering here!
Yay

[Storm Struck]

All eyes on the sky today and again we live in hope .
A warm 21C at the moment with a breezy N-NE wind, also some mid level cloud coming through from the west with a few showers in it.
I was busy watching the lightning flashes to the west last night when a long thin cloud simular to the one Lacertae seen earlier in the evening came up very fast from the westerly direction.
The low cloud line passed over with a breezy Westerly for about 5 minutes then died down.
I have heard the Avon river mouth is quite high this morning as well as the ocean, must be a combination of a full moon with king tides, and the strong onshore flow from this system.
Cheers
Jason.

[Lacertae]

Nice pic of the Pileus cap Tim !

[CHCH Weather Chaser]

25.7 degrees here very warm morning. Cloud cover jsut starting to spread from the west now, fairly high but some nice CU's around as well. Thunderstorms and heavy showers in the forecast late in the day.Earlier was saying thunder possible and isolated but now says this:
"Canterbury
Patchy rain, some thundery falls this afternoon and evening as a southerly change spreads north. Showers tomorrow, some heavy in the afternoon. "

Interesting afternoon we will wait and see. Yesterdays rainfall of 3mm will find us back to square one with the fine spells and windy weather from yesterday and warm temps of this morning.

[Tornado Tim]

Oh man another Pilues cap has just formed.
That means that the updrafts on this cloud are 32 to 48 kph.
That is high when a Calvus cloud can pick up a slab of air and thrust it upwards, and cause the the slab to condence and make it look nice and smooth eh?
Here is 3 pics, this formation is better than the other 1 posted:

[carrot]

Looking pretty good atm for this arvo activity me thinks.

[Razor]

Looks like the NW has swept through which will kill much chance of thunder now.

I agree with john, its looking like a poor thunder year. All the southerly changes have been so weak this year.

However, I love to be proven wrong. It happens, once a decade or so

[Razor]

Looks like the Mestervice agree too, only predicting a few showers now, possible heavy. The thought of a decent rain band has been shelved.

[Storm Struck]

There actually wont be any NW up high because the Low at around 989hpa will be sitting over us around 1pm, so very little winds should mean good vertical development.
No ridging for quite awhile until the air turns more SW this evening.
Had a few light spots of rain here before, but early days yet.
Cheers
Jason.

[CHCH Weather Chaser]

Yes few spots here now and the wind has died down completely. The wind direction here is NE, had no NW here today.....North very briefly but that was it. Heavy showers forecast tomorrow afternoon as well. Radar starting to look more interesting actually.

[melja]

Nw is a killer at any level with low DPs and not much heating going on with all the high cloud!
I think we dont get T/S when its a dry summer in canterbury because of the lack a moisture, maybe someone can look back and see if the good T/S summers happend when we wernt in drought conditions

[spwill]

dry summer in canterbury because of the lack a moisture,

Looks to be on the change with some southerlies showing up in the long range mix.

Very warm here with 18C dewpoints overnight but the air is drying now, currently sunny 27C , some towering Cu out to the east.

[CHCH Weather Chaser]

Looks like brief heavy rain for pretty much entire south island on sunday at 1am on the 7 day rain maps just been updated. Something to look out for, ofcourse it will probably change

http://metservice.com/default/index.php ... st_7daytas

[Manukau heads obs]

always surprising how much the city is warmed by the land to the NW of it in a NWer ...only 23oC max here (NW wind is coming off the Tasman for for us)

[Storm Struck]

Plenty of scatterd CU about with a few darker bases more NW of here at the moment.
I dont really expect too much until this evening, as a cooler pool of air drags up with the SW change.
Breezy onshore NE wind which i hope sticks around for the rest of the day until the change, good to see that upper level cloud move on too allowing the clouds to develope more freely.
An interesting low system at the weekend and maybe a wet xmas day even .
Cheers
Jason.

[Tornado Tim]

Brian, What does it look like in Manukau today? Vertical Development?
I wont get a bit of the storms develop over here as the wind is NE, Damb it.

[CHCH Weather Chaser]

Some clouds out there moving from NE direction and some SW now

[Manukau heads obs]

there was some very nice development around the east auckland area at around 1pm
but thats all died away now
17C DP here at the moment

[Nev]

always surprising how much the city is warmed by the land to the NW of it in a NWer ...only 23oC max here (NW wind is coming off the Tasman for for us)

Interesting. Would your higher elevation make much difference?
Auckland Aero recorded 25.5°C at 1pm. Just hit 26.0°C in our back yard.

[NZstorm]

Lifted index chart for NZ for 4pm (0300Z) today based on GFS 1800Z run.

LI's try to dip below zero over a large portion of the country but the upper air is warmish and the dewpoints are falling so no convection. A convergence area over mid Canterbury suggests a tstorm could be possible there.

[Storm Struck]

Very nice looking radar at 3pm i would say around the Waimate area with even a slight hint of purple.
Sitting outside when the sun peeped through at times before it was absoululty schorching hot.
Quite abit of scatterd CU about now and ive just noticed the wind is more E-SE.
Cheers
Jason.

[CHCH Weather Chaser]

Plenty of unstable looking cloud out there and a rain band that is not too far off now at all just south to the city. Could be something good out of this, feeling 70% confident now!