Upper Trough, Inland North Island, February 20th

[Tornado Tim]

Looks like an upper trough will pass the North Island in the afternoon and there is a possibility of a storm or two in inland regions.
Providing upper air is cool enough and upper support (such as the upper trough) comes in the right time there is fair risk of a storm, otherwise it will be a heavy heat shower type setup.

Take what we can get I suppose

[Thunder]

Maybe if a small low forms on the coast down here something could happen here to, figures aren't great but would take what we can get down here to. Your chances would be better though.

Perhaps more south canterbury at this stage.

[Manukau heads obs]

looks unstable here already...

[Tornado Tim]

Morning all,
Yes It does look unstable, the upper trough to the east has quite a bit of Cumulus Congestus sustaining any convection overnight. A very varied sky here this morning with cirrus, altocumulus and unstable low level cumulus.

Will be interesting to how the day pans out.

[Richard]

Its even looking a little unstable here as well,with cloud moving from the north this can often be a good sign,so who knows ,maybe

[jamie]

Woohooo i just got moved in the office to a window seat. I now look what i think might be NE. I am looking right out the the colliflower skies. Looks good already.

[Nev]

This morn's T-Storm update hasn't changed too much from last night's...

MetService - Severe Thunderstorm Outlook

Valid to: Midnight Monday 20 Feb 2012
Issued at: 8:23am Monday 20 Feb 2012

Over the North Island increasing instability and converging winds inland are forceast to give showers in many areas this afternoon. A moderate risk of thunderstorms is indicated for inland areas from Waikato down to Taumarunui and Taihape and southwards across much of Hawkes Bay and Wairarapa. Any thunderstorms that occur in these areas will be reasonably slow-moving leading to localised heavy rainfall rates up to 25mm/hr. A region from the Taihape ranges down through southern Hawkes Bay and northern Wairarapa is picked out with a low risk of thunderstorms becoming severe (25-40mm per hour) late afternoon and early evening. Convective showers should die away in all areas this evening.

For the South Island, isolated showers are expected to develop on the foothills of South Canterbury and in parts of Otago and Southland in the afternoon, but these are not expected to turn thundery.

[NZstorm]

Looks like a marginal set up today. Showers will certainly develop but not so much thunder activity. Just isolated brief storms over the central NI by the looks.

Looks like the country will be under the influence of upper troughing through to Thursday.

[Tornado Tim]

Cbs and some isolated thunderstorms are occurring in the CNI, a cell has just gone up south of me which had quite a bit of pileus when it was still developing.

500hpa wind is a bit keen from the west.

[jamie]

there is a nice little cell that looks to be near whatawhata. might go a drive. have nothing better to do

[spwill]

A few showers have developed over the hill country of West Auckland, photo of a Cb over the Waitaks

[NZstorm]

A couple of anvils appeared in the west this afternoon from sea breeze convergence.

Can see t/cu and cb tops to far south also.

[spwill]

A thunderstorm over Northland and the cell near Hamilton looks good

[Justout]

Heavy rain with thunder and lightning south of Te Awamutu

[Tornado Tim]

Very nice storm to west pumping out quite a bit of distant thunder......

Saturated updraft and outflow structure is awesome!

[NZstorm]

Outstanding photo Tim!

A zoomed in pic taken from Grey Lynn of distant cb to south.

[jamie]

Wow this is a brilliant storm here.

[Tornado Tim]

Apparently the storm had a warning on it....

This warning affects people in the following local government areas:
WAIKATO, HAMILTON CITY and WAIPA.
At 07:45 pm, MetService weather radar detected severe thunderstorms near HAMILTON, WHATAWHATA, NGAHINAPOURI and TEMPLE VIEW.
These severe thunderstorms are moving towards the southeast, and are expected to lie near HAMILTON, OHAUPO and HAMILTON AIRPORT at 08:15 pm and near HAMILTON, CAMBRIDGE, TE AWAMUTU, OHAUPO, LEAMINGTON and HAMILTON AIRPORT at 08:45 pm.
These thunderstorms are expected to be accompanied by very heavy rain.
Very heavy rain can cause surface and/or flash flooding about streams, gullies and urban areas, and make driving conditions extremely hazardous.
A Severe Thunderstorm Watch remains in force for HAWKES BAY, MANAWATU, TAIHAPE, TARANAKI, TARARUA, TAUMARUNUI, TAUPO, WAIKATO, WAITOMO and WANGANUI.

They seem to be using New Plymouth radar for this storm warning, rather odd, perhaps its getting a better pickup.

[jamie]

no way the taranaki one picks it up better. the BOP one has been the best for hamilton ever since it was put in. I just looked at the taranaki one and it hardly picked it up.

that storm exploded for about 30 minutes but died very quickly. strangly only dropped 2 CGs according to transpower. must have all be IC.

we also had an awesome sunset here.

[Tornado Tim]

no way the taranaki one picks it up better. the BOP one has been the best for hamilton ever since it was put in.

Yea I was thinking that, also the BOP has Dual Polarization so why on earth use the NP one which doesnt have it.

This storm this evening was real visual treat
Here are some photos in sequence attached.

The first shot in the other post was when it started dishing out the thunder, the storm started to develop right to my west and then got dragged along SE'wards, while still containing quite a bit of thunder, no lightning was visible yet.
A gust front developed on the SE side of the storm and started to surge SE more promptly and the thunder started to cease. I then took pictures of the northern side of the storm and took some shots of the structure and the sunset.
I only saw 1 CG with this storm, most of the lightning was IC.

we also had an awesome sunset here.

Yea sunset was really good especially when a storm is ahead of it

[GreggWard]

We had a storm pass to the north of Palmy, between 4:00pm and 5:00pm. I was stuck at work so couldn't venture out and chase it. My wife, who works in Feilding, said that they heard quite a bit of thunder from it. This storm went briefly Severe Thunderstorm Warned, on the eastern side of the Tararua's just south of Pahiatua. The warning made mention of large hail. I didn't manage to take a copy of the warning.

[GreggWard]

Great photos Tim.

[NZstorm]

Thanks for the pics Tim. Looks like the cb tried to develop into a squall line type structure.

[NZstorm]

We got a heavy convergence shower here last night with 10mm at Grey Lynn around midnight.

[Nev]

We got a heavy convergence shower here last night with 10mm at Grey Lynn around midnight.

I see Ricky has 1.4mm/min, which I assume equates to 84mm/h? Quite a downpour!. Sounds similar to the 12mm rogue cell we had here early Saturday morn.