Unsettled - July 21-24

Manukau heads obs · Fri 22/07/2011 19:48

wow, a tornado in Waipu!
that frontal band north of auckland now must be the same one that produced that?
the picture in the first link Nev sure looks ominious!

CbFan · Unread post by **CbFan** » Fri 22/07/2011 20:04

Just got pasted by a line of intense Cb's throwing CG's about 30 min ago, just north of Kerikeri. Got really stroppy for about 15min or so. Some real low frequency, long duration thunder.

CHCH Weather Chaser · Fri 22/07/2011 20:12

The amount of tornados occurring in NZ suddenly is a bit concerning...

Manukau heads obs · Fri 22/07/2011 20:19

The amount of tornados occurring in NZ suddenly is a bit concerning...

blame it on global warming I say
more surface heat and more surface moisture,means more fuel for weather systems to produce tornadoes

Tornado Tim · Unread post by **Tornado Tim** » Fri 22/07/2011 20:25

CHCH Weather Chaser wrote:The amount of tornados occurring in NZ suddenly is a bit concerning...

But really one could say that they are getting reported more often......

Michael · Unread post by **Michael** » Fri 22/07/2011 20:39

People have access to cheaper/better apparatus,cameras,cellphones etc etc wheres in the old days it was newspapers,I have clippings from those days mentioning them time to time.

CHCH Weather Chaser wrote:The amount of tornados occurring in NZ suddenly is a bit concerning...

NZstorm · Unread post by **NZstorm** » Fri 22/07/2011 20:48

Interesting to see the tornado report. Must have occurred on the frontal boundary as you suggest Brian. The surface dewpoint and temperature at Whangarei airport were both 15C late afternoon, so saturated air.

Nev · Unread post by **Nev** » Fri 22/07/2011 20:49

Manukau heads obs wrote:wow, a tornado in Waipu!
that frontal band north of auckland now must be the same one that produced that? ...

Yes, that heavy band has just hit here.

I've updated my post overleaf to include a radar image. You can clearly see the 2 intense (if not short lived) T-storms just before the event.

David · Unread post by **David** » Fri 22/07/2011 21:05

Has started raining pretty heavily in Howick now.

Razor · Unread post by **Razor** » Fri 22/07/2011 21:29

CHCH Weather Chaser wrote:The amount of tornados occurring in NZ suddenly is a bit concerning...

Why? Like others say everyone these days has more access to share vids, photos and first hand reports. I see no evidence that there has been any dramatic change from the norm.

David · Unread post by **David** » Fri 22/07/2011 21:36

David wrote:Has started raining pretty heavily in Howick now.

Had 9mm in an hour. I see the moderate thunderstorm risk extends down onto east Auckland tomorrow, might get lucky

Philip Duncan · Unread post by **Philip Duncan** » Fri 22/07/2011 21:43

Razor wrote:
CHCH Weather Chaser wrote:The amount of tornados occurring in NZ suddenly is a bit concerning...
Why? Like others say everyone these days has more access to share vids, photos and first hand reports. I see no evidence that there has been any dramatic change from the norm.

Agree with you Razor

iomkiwi · Unread post by **iomkiwi** » Fri 22/07/2011 22:04

getting real close now - less than 2 secs from flash to bang

Storm Struck · Unread post by **Storm Struck** » Fri 22/07/2011 22:17

To me global warming is a lame excuse for politics to put thier foot in the door and make a country loud and proud for no real reason, i think its just climatical shifts that the earth goes through every hundred thousand or so years we have had ice ages etc in the past before nothing to say that wont happen again.
Of course it doesnt happen just like that it would be over time very gradual increases and changes in weather patterns and records, as we are seeing the last 10 or so years across the world.

spwill · Unread post by **spwill** » Fri 22/07/2011 22:19

More storms forming over the water just NE of the Bay of Islands currently.
Certainly some interesting weather for Northland today with that tornado.

Nev · Unread post by **Nev** » Fri 22/07/2011 22:25

Jason, please stay on-topic!

iomkiwi · Unread post by **iomkiwi** » Fri 22/07/2011 22:40

This thunder seems to be causing someting in the neighbourhood to short out, the tight groupings to my SSE are happening just after the louder rumbles, the boltek goes crazy for a minute or so.
http://www.kerikeriweather.co.nz/wxlightning.php

Tornado Tim · Unread post by **Tornado Tim** » Fri 22/07/2011 23:00

iomkiwi wrote:This thunder seems to be causing someting in the neighbourhood to short out, the tight groupings to my SSE are happening just after the louder rumbles, the boltek goes crazy for a minute or so.
http://www.kerikeriweather.co.nz/wxlightning.php

I think whats happening Alan is your Boltek antenna is picking up the individual strokes in a lightning "flash" since its so close.
Since Nexstorm plots strokes as strikes your getting a tight grouping where that nearby flash occurred.
I saw your boltek go to 427p/min at one stage (which is very plausible) as you where getting stuff very close.
Eg: the Boltek has enough info to open close the gateway to capture the strokes properly.
Distant lightning isnt so good as the the individual strokes are less definable.

The Strokes I am getting from that storm your way are actually quite weak here (ratio of about 2/10 per stroke)
Avg Amps: 32 (which is fairly weak) but the CG Avg amplitude I am getting is a little higher: 36.5.
Of note: that storm spat out a nice +CG which was around 83amps

iomkiwi · Unread post by **iomkiwi** » Fri 22/07/2011 23:06

Thanks Tim.
I'm keeping an eye on those cells to my NNW which are both making a beeline for me, looks like they might join up here around midnight!

iomkiwi · Unread post by **iomkiwi** » Fri 22/07/2011 23:36

I have a couple of other cameras up my mast, currently set on motion detection, check the archive pages from here for the northern and western cameras
http://www.kerikeriweather.co.nz/wxtest.php
- definately some close strikes on that western cam

Manukau heads obs · Sat 23/07/2011 06:45

spounds like a fun night up north
that heavy rain band is about to hit the auckland area, and still has some (weaker) lightning in it

spwill · Unread post by **spwill** » Sat 23/07/2011 07:00

Have just seen lightning out to the NE, distant.

Nev · Unread post by **Nev** » Sat 23/07/2011 08:00

Received 33m here last night from a few heavy falls, including a very intense but seemly isolated cell going by the 1am radar.

Tornado Tim · Unread post by **Tornado Tim** » Sat 23/07/2011 08:17

Some storms over Coromandel atm......

NZstorm · Unread post by **NZstorm** » Sat 23/07/2011 08:50

The 12Z NZWP sounding shows some interesting low level shear with a ESE on the surface and NE at 850mb. The 0-3km SRH (storm relative helicity) was -193, which is a favourable number for a rotating updraught. These numbers are representative of Waipu yesterday afternoon. The upper flow was weak though (500mb 20kts) which means the cb would have been short lived, more the pulse type.

Looks like a isolated short lived storms possible today with any convergence over the north. GFS has reasonable looking CAPE values over northern areas.

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