Thunderstorm Potential Early Dec 2009 in the North

[Tornado Tim]

GFS is plotting some nice unstable air out over the tasman atm, although the models are a little to far out to call it at this point of time.
A nice humid NW flow is expected to come with CAPE from the Tasman and drag itself over the north of NZ at this stage.
DPs are expected in the mid to high teens around early december with a expected cool 500mb temperature around Northland to South Waikato (around -15 to -18°C)
If some DTSH gets going we may very well have a "thunderstorm event".
I have attached a Skew-t chart for one of the "HOT" days:
Cross your fingers and lets hope it pans out... LOL

[David]

Seems like instability coming up for northern area for possibly at least 4 or 5 days from 1st December. I made this meteorogram for Auckland here: http://www.ready.noaa.gov/ready/cmet.html

The text results for this output show that at the peak instability, CAPE is modeled at 1023 and 'Best 4 Layer Lifted Index' modeled at -3.4.

Let's dearly hope this remains in the models northerners

metgram28nov09.gif

[NZstorm]

I like the 100kt jet stream in the north Tasman from early week. Thats always a good sign for some interesting weather over the North Island. Should see some major thunderstorm activity fire out in the Tasman next couple of days. Thunder chances reach the upper North Island Tuesday by the looks.

[tgsnoopy]

Be careful, don't Jinx it... I'm not holding my breath, but it would be good to finally get a show. Pity I'm going to have a busy week by the look of things.

[Tornado Tim]

As NZstorm said, A very nice Jet stream coming around soon:
That means the storms will have a bit of tilt on them, meaning that they can last longer

[jamie]

Tazy sea is lighting up nicely tonight off the NSW coast.

[NZstorm]

If there is sufficient heating tomorrow afternoon could see Isolated thunderstorms pop up from Northland to the Waikato. Surface dewpoints will be around the 17-18C mark and upper level air will show some cooling on today. I'm hoping we can get a bit of a surface NE going to converge with the general NW flow.

[KiwiWeather]

Fingers crossed, Steven

[jamie]

whats the word on tomorrow. i dont really have time these days to go over all the models and work it out for myself. are there good chances of thunder storms developing around the waikato and other parts of the country tomorrow afternoon?

[spwill]

some day time heating tomorrow would be good, see what the day brings

[NZ Thunderstorm Soc]

Good luck to you.

JohnGaul
NZThS

[Tornado Tim]

MS have put some areas of Auckland and Waikato under a "high risk" but i am thinking that there is going to be a lack of DTSH and combined with that a warmish upper air temp. So if any CB's do develop i think it will be very hard for them to turn "lightning active".
I will have a look at morning models and then come back....
Heres a skew-t for Matangi around tomorrow at 4PM:
(it doesnt look good)

[NZstorm]

Yes, the cloud cover puts a question mark on todays instability although it doesn't seem as bad this morning. Its good to see the surface flow NNE 10kts which is needed for convergence. Tim, given the good lowlevel moisture the upper air looks cool enough for convection. Should see isolated thunderstorms pop up this afternoon over northern regions. Trigger temperature looks to be around 23-24C mark.

[Manukau heads obs]

unstable looking skies out to my west in the upper level clouds
even some Kelvin wave clouds too at one stage , good sign

[NZstorm]

The gfs likes Northland with cape 800j/kg+ at 4pm. But cape is such a fluid number. It will come down to where the surface heating can occur.

Upper flow indicates any storms that develop will have some speed shear and will move quickly ESE.

[spwill]

Great to see that thick low cloud has gone however a mid to high level cloud sheet is drifting down from the north , how will that affect the day.

[Peter]

What does the acronym DTSH stand for?

[David]

Peter that's day time surface heating

Yes it's good to see the light NE breeze here this morning and brighter skies (although cloudy currently).

[Manukau heads obs]

where do you find the thunderstorm outlook /watch on the new M/S web site now?
thanks

[David]

where do you find the thunderstorm outlook /watch on the new M/S web site now?
thanks

http://www.metservice.co.nz/national/warnings/index
Then the various warning/watch pages are all there on the sub-menu

[Tornado Tim]

where do you find the thunderstorm outlook /watch on the new M/S web site now?
thanks

Its hard to find eh Brian, heaps harder then it was b4.

[spwill]

looks like the NW will keep any shower development east of here, some towering Cu in the east, Radar shows some weak showers Northland to Waikato.

Currently 25C dewpoint 19C , a very warm combination, not much in the way of sunshine this morn, afternoon is looking better for sunshine.

[Manukau heads obs]

ah, I looked at the warning page but missed those links

have had a few showers here, and peaked at 22C despite cloud cover


http://www.metservice.co.nz/towns-cities/auckland

shows 1 minute updated temperature and wind info in the last 10 minutes
good

[David]

24ºC here, wind is still light NE. Hopefully the NW doesn't push in all the way off the eastern coastline!

[NZstorm]

The whenuapai sounding shows drier low level air than I was expecting to see. The low level dewpoint on it is 14C. Could that be an error?

Yes, the NW wind is kicking out the NE so chances of convergence look to be diminishing.