Thunderstorms mon 6th

squid · Unread post by **squid** » Sun 05/02/2006 11:26

Could be an interesting day what does everyone think

An approaching upper trough will move over North Island Monday afternoon and evening. As it does so, it will significantly cool the temperatures in the upper atmosphere destabilising the atmosphere over the upper half of the North Island.At this time, there is some conflict in our guidance as to just how cold temperatures aloft will get. But despite this, there is a high risk of thunderstorms occurring in areas of wind convergence tomorrow afternoon and evening from Taumarunui to western Bay of Plenty and up to Northland.

In Waikato, Waitomo and possibly western areas of Bay of Plenty, there is a moderate risk of severe thunderstorms capable of delivering heavy downpours up to 40mm/hr due to their likely slow motion, and hail in the 20 to 30mm range.These storms have the potential to cause local flash flooding and hail damage.

Outside this area from central Bay of Plenty to northeast Taranaki and up to Northland, there is a high risk of thunderstorms giving significant rainfalls and hail, but not quite as intense as those in the severe thunderstorm area.

spwill · Unread post by **spwill** » Sun 05/02/2006 11:53

It's a shame we have lost a lot of our moisture from last week, dewpoints now around 13, 14C.

Willoughby · Unread post by **Willoughby** » Sun 05/02/2006 18:19

Looks good for thunderstorms tomorrow.. will need a very solid moisture feed in place as the surface winds look as though they'll be predominately southeasterly.

spwill im glad the high dewpoints are gone.. that means you can actually see and photograph the Cbs!

. instead of everything being obscured by low cloud and constant heavy downpours!

NZ Thunderstorm Soc · Sun 05/02/2006 19:41

No chance, sorry.

The anticyclone will be moving in too quickly to allow the upper air to destablelize any atmospheric conditions, mind you Hamilton could in the firing line as that is a very thunderous city, well it seems to be at the moment

Things look very good down here for Wednesday,possibly Thursday, so folks down here, keep your fingers,legs and arse crossed for something exciting to happen

JohnGaul
NZTS

spwill · Unread post by **spwill** » Sun 05/02/2006 21:13

spwill im glad the high dewpoints are gone.. that means you can actually see and photograph the Cbs!

Varies with different situations but yes generally with the very high dewpoints there's a lot more low cloud to burn off.

NZTS said,

Things look very good down here for Wednesday,possibly Thursday

Yes, the risk moves north on Thursday

NZ Thunderstorm Soc · Sun 05/02/2006 21:25

spwill wrote:
Yes, the risk moves north on Thursday

...knowing NZTS's luck, the risk has more potential north, especially around Hamilton,than down here.

...but then
JohnGaul
NZTS

Manukau heads obs · Sun 05/02/2006 22:26

wih the SWer today the salt spray was back here..cutting down on the visibility
.in the easterly the visibility has been very good...

i see eastern BOP got some rain overnight from a flick of the cloud that was left over from tc jim....(which did go NW as the models predicted (what was left of it)

dew points have been rising all day here....now 14.8oC DP

Willoughby · Unread post by **Willoughby** » Sun 05/02/2006 22:42

Some very crisp, beautiful towering cumulus this evening far away to our southeast.. Rotorua registering some shower activity this evening.

Wind has just turned southeast here.. it looks to be quite gusty in Taupo and other central places.

Manukau heads obs · Mon 06/02/2006 05:58

it was 2:30am before we got the SE change here!
could be good to go for thunderstorms here, with that SEer, as they will build up out of the waikato and then move up here...
as long as the sw sea breeze does not get up too much...

NZstorm · Unread post by **NZstorm** » Mon 06/02/2006 08:29

Some great looking Altocumulus castellanus this morning indicating unstable air in the mid levels.

tgsnoopy · Unread post by **tgsnoopy** » Mon 06/02/2006 08:31

Ok, some action at last... Not too sure about being out in hail 20-30mm in size though! Petrol station forecourts could be the order of the day I think (as my car only has fire, 3rd party & theft insurance).

Is anyone planning on heading over to Hamilton which is roughly the centre of this event for a look? I'm considering going up to the top of the Kaimais or further if it shapes up ok.

Thoughts anyone? Foggy, what are your plans this afternoon?

squid · Unread post by **squid** » Mon 06/02/2006 09:06

still looking very good for some action today coul someone tell me what the current dps are now please for northland/auckland area cheers

spwill · Unread post by **spwill** » Mon 06/02/2006 09:19

Some great looking Altocumulus castellanus this morning indicating unstable air in the mid levels.

Yes, they look like Towering Cu.

Partly cloudy here 19C, dewpoint14C.

Manukau heads obs · Mon 06/02/2006 09:37

i see a tower has gone up to my SW
and the animation on the web cam shows the upper level winds are form the NW, so its leaning to the SE...
update, now blown off tops to the SE with a upper level NW wind...
and a surface SE wind...

wind tending more southerly here now..

i think pukekohe could be a good spot to be...

squid · Unread post by **squid** » Mon 06/02/2006 09:47

a large tower has gone up to my SW also right on the coastal boundary just appears to be sitting there plenty of other delevopment all round pretty good for this time of day

C-Nimbus · Unread post by **C-Nimbus** » Mon 06/02/2006 10:45

yes some really good looking castellanus type (turret) mid level and upper level clouds indicating the cooler upper temps and destabilising atmosphere.

Very exciting indeed, and its only 10:45!!!

Few towers up over helensville way

its looking pretty damn good thats for sure

tgsnoopy · Unread post by **tgsnoopy** » Mon 06/02/2006 10:46

Ok, all the batteries (digital video & digital still) are charged and the car is full of gas. Fingers crossed!

No takers for a group gathering?

C-Nimbus · Unread post by **C-Nimbus** » Mon 06/02/2006 10:47

also to add, a weak convergence line has developed over whangarei, and it appears that a good multi cell storm is a 100km or so of the west coasrt of auckland

spwill · Unread post by **spwill** » Mon 06/02/2006 11:24

tgsnoopy said

No takers for a group gathering?

Have to wait and see what and where things develop.

Cu starting to build on the Waitaks, West Ak.

Manukau heads obs · Mon 06/02/2006 11:29

i would be in...have to milk cows this arvo...but could be after that ...
middle layer cloud has been stopping heating over northern waikato, but thats starting to break up now

best action has been over the sea so far...but once the land heats up...

squid · Unread post by **squid** » Mon 06/02/2006 11:45

1st storm of the day very solid and crisp anvil to my S SW just off the coast and it only 11 45am

NZstorm · Unread post by **NZstorm** » Mon 06/02/2006 11:46

Some surface based t/cu over West Auckland now. Temp now 23C, dp14C. Not overly moist but temp will top 25C today.

Will be interesting to see todays sounding. Hopefully upper air is cooling.

Thunder · Unread post by **Thunder** » Mon 06/02/2006 11:56

Hopefully some good reports at the end of today!!

The models were definatley signaling thunderstorms for today so something will happen.

I'd join ya Tgsnoopy but that usual circumstane of being stuck down here is problematic....

Cheers

ricky · Unread post by **ricky** » Mon 06/02/2006 12:08

Heading back to Akl from Taupo today so I'll go in the direction of anything that looks interesting..

Mostly clear sky here in Taupo, quite cool ~19C and windy.. a little Cu above the mountains and to the North and a bit of streaky high cloud

spwill · Unread post by **spwill** » Mon 06/02/2006 12:14

Towering Cu over Waitaks, West Auckland.