Active Trough crossing N.I. - June 20/21

[jamie]

Can't sleep so thought I would have a look at the trough approaching the country. Looks fantastic on the sat images at the moment. Here's hoping it holds together and belts the west coast of the north island.

[Manukau heads obs]

certainly lightning active at the moment

its moving fast, might get a bit too far ahead of the main trough axis by the time it gets here?

[Tornado Tim]

Looks quite good doesnt it, hopefully it has some good structure when it comes in

Keep an eye on late tomorrow afternoon also.

[jamie]

That's a good point Brian. It does look like its moving faster than the main cold pool.

[Tornado Tim]

A faster approaching front can actually enhance the forcing making a more powerful updraft.

The lightning activity may die down this morning, like it usually does, hopefully it will spark up again in the afternoon if it does that.

[NZstorm]

GFS has the front crossing Auckland early evening. These systems often break up as they hit land so we'll see what happens.

[jamie]

MS thunderstorm chart looks ok. This is the sort of system that requires the sea isnt it? So as soon as it hits the land its going to fall apart. Hopefully it is in a cycle of ramping up just before it hits the coast so it still has some guts to it as it crosses.

Metservice: A series of troughs are expected to move onto central and northern New Zealand from this afternoon, while temperatures in the upper atmosphere gradually cool. There is a high risk of thunderstorms for Northland, Auckland and western Waikato this afternoon and evening. This risk then spreads into western Waitomo,north Taranaki, Coromandel Peninsula and Bay of Plenty at night. These thunderstorms may produce localised rainfall rates of 10 to 15mm/hr, small hail(note, hail of 10 to 15mm diameter is possible in western Waitomo and north Taranaki this evening), strong wind gusts of 90 to 110 km/h, and the chance of a few small tornadoes. A low risk of thunderstorms extends over the rest of Waikato and Waitomo, south Taranaki, the Marlborough Sounds, and the northwest of Nelson as depicted on the chart.
No thunderstorms expected over the rest of the country.

For later reference

[Manukau heads obs]

one lightning active CB to the west of norhtland I see
http://www.blitzortung.org/Webpages/ind ... bpage_0=21

[David]

Well it seems no one got thunder based on the quietness in here Just the odd shower here today apart from a period of rain mid-late afternoon.

[Manukau heads obs]

there was one strike off the coast here around 3:30pm as the front came through
I heard if very sligthly the thunder, and my boltec picked up a close strike
Jim Hicky mentioned a thunderstorm near the manuakua heads for that time....was surprised he mentioned it as it was a one stike wonder, and off shore...I wonder who reported it ...

Ricky is getting lots of rain at the moment,....looks like you are just missing that

[NZstorm]

We had a bit of a downpour here early evening.

Nice to have another mild day with 17C.

[Michael]

Its been quite wet all morning it was here,a 3 hour or so showerless overcast spell about in the afternoon then more after dark,not cold tonight.Dont think much will amount tonight as far as thunder.

[jamie]

There has been some nice looking convection going on around the waikato from about midday. The radar shows showers poping up all over the place. Its amazing to see that happening on the shortest day of the year. Its quite warm out there too.

Ive got a grand view out my office window of a nice popcorn updraft feeding the cell which is growing of the kaimais/mt te aroha

[Thunder]

Total totals are high over that area today, I wondered if there could be some convection.

[Aucklandstorm]

I'm sure I Just saw a funnel out west Auckland, that even possible with what we got ATM? Dam getting to dark now to see.

[Manukau heads obs]

cloud formed from NZ steel

[David]

There were lots of showers in the city at uni this afternoon, some heavy bursts - only 0.8mm in Howick though!

[spwill]

A nice day until mid afternoon when some showers arrived, some of the showers did look heavy , just light falls here. Light winds , max 16C.