Page 1 of 4

Subtropical rain North Island, from 5th Dec

Posted: Tue 04/12/2007 15:24
by David
One of the weather Zone models has about 80mm out of this system, metvuw I counted about 100mm, this site http://www.weather-forecast.com/locatio ... sts/latest has about 90mm, and ogimet has about 60mm, so looking good for some substantial rain at this stage. Metservice also have a severe weather watch for Northland now and have a moderate confidence of heavy rain reaching warning criteria over northern NZ from 6th-8th December. The only strange thing is that the models also have moderate pressures over us due to the large anticyclone to the east - hopefully won't affect the amount of moisture in the NE airstream.

Re: Subtropical rain North Island, from 6th Dec

Posted: Tue 04/12/2007 16:27
by Manukau heads obs
might just get thick high cloud and some spits out of it , these things dont always deliver
but rain would be welcome, starting to dry out around here now

Re: Subtropical rain North Island, from 6th Dec

Posted: Tue 04/12/2007 18:42
by NZstorm
Given the very high dewpoints (20C) headed in our direction there looks to be the potential for a few thunderstorms (25mm+/hr) over northern NZ with this system (Thursday and Friday). Too early though to make a confident forecast but atleast this system will be something to watch rather than the anticyclonic stuff we have had to put up with of late. :lol:

Re: Subtropical rain North Island, from 6th Dec

Posted: Wed 05/12/2007 06:49
by Manukau heads obs
shocked to see its raining this morning (just a bit) with a 1021 baro (up from last night)
(mind you I have trouble with the my internet connection at the moment so have not been watching enough what was heading our way!)

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 13:56
by NZstorm
Yes, I was suprised to see some decent rain falling first thing this morning.

Tomorrow is looking a high risk to me for a few thunderstorms over Northland given the high surface dewpoints.

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 15:29
by Manukau heads obs
rain clouds gathering more now
according to the synoptic prognosis we are going to have very humid and warm northerlies for in behind this warm front, and then a high over the SI is going to direct cold and dry easterlies up and under the shallow low.....bang, big potential for some real action!

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 16:10
by Manukau heads obs
ah, i see the metservice are already on top of that:
A cold front bringing cooler air moves onto the South Island today.
This front should meet up with the warm air over the central North
Island tomorrow, and this clash of airmasses is likely to lead to an
active frontal zone developing over the central North Island.

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 20:16
by jamie
Sounds like this clash of airmasses is going to be good. heres hoping :D

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 20:34
by NZ Thunderstorm Soc
Yawn :(
What about poor old Canterbury?
Another hideously boring southerly change tomorrow :evil:

JohnGaul
NZTS

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 20:40
by NZstorm
I hope the 'clash of the airmasses' is over the central NI as I would like to see the sun out in Ak tomorrow afternoon. Daytime heating will help destabilise the air. Any sunshine should see temps rise to the 25C mark.

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 21:02
by David
NZstorm wrote:I hope the 'clash of the airmasses' is over the central NI as I would like to see the sun out in Ak tomorrow afternoon. Daytime heating will help destabilise the air. Any sunshine should see temps rise to the 25C mark.
Good point you've got there - although the wind outside is really picking up now, if we get some sun tomorrow afternoon its perfect breeding grounds for heavy thunderstorms popping up. We need this action after such a boring November! :D

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 21:08
by NZstorm
Thats the plan David but knowing our luck it will stay overcast with rain all day here in AK tomorrow. :lol:
Northland will be better placed for some sunshine tomorrow and pop up thunderstorms.

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 21:16
by spwill
'clash of the airmasses'
I see Elton John is doing an outdoor concert in New Plymouth tomorrow night, there will be no Candel in the Wind.

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 21:27
by Manukau heads obs
cant see much sun tomorrow.....
convergence of winds over the area along with topography and some brightening of the skies could be enough of a trigger (if the wind drops from what it is now)
6.7mm here
usefull, but need more , for the farmers

Re: Subtropical rain North Island, from 5th Dec

Posted: Wed 05/12/2007 22:04
by Cameo1
Looks like a bit of lightning over northland at the moment :D

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 03:44
by Willoughby
At the moment? What about all night! :o
Dewpoint to 19C already in Whangarei, 8.6mm here so far which is very welcome. :)

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 06:18
by spwill
Just very light rain here overnight ,current temp 18C, dewpoints a humid 18C.
Looks very unstable over the far north with a few Thunderstorms about.

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 07:03
by NZstorm
Met Service have under done the max temps today for the north. I see Whangarei they are going for just 22C.
I guess it depends on how much daytime heating there is but in these humid airmasses the temperature can shoot up with just a little bit of sun.

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 07:17
by David
Bring this heavy rain on! 17mm in the last hour here, but its tapered of to only moderate rain now :(
edit at 7.36: 21mm in the last hour :D

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 07:47
by spwill
21mm in the last hour

Local downpour, just light rain here but there is heavy stuff just to the north

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 07:52
by Manukau heads obs
15mm here now, nice.
I see the clearance is coming onto the far north now
so maybe by 4pm today it will clear in the auckland area?

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 10:52
by David
A very welcomed 40mm here for this system so far, all soaked up by the ground too :)

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 11:08
by Willoughby
You're lucky with the 40mm! 16mm here so far with light rain falling now. Temp 20C/ Dewpoint 19C 8)

Might be interesting what pops up behind the boundary line in the far north this afternoon.

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 12:16
by David
This is weird, my digital and older manual rain gauges both have 40mm, yet a normal open container I put outside has 52mm. I very much doubt this. Maybe it's because I had it against our deck and in the heavy downpour there was a significant amount of splash maybe?

Looks to be cloudy for a while now, the rain seems to have moved off eastwards, I can't see the temperature going much above 20C unless the sun makes an appearance. Hoping for some more downpours out of this system, the 21mm in an hour this morning was the second heaviest fall for the year here (based on 1hr totals only), close to the 23.5mm/1hr early on 30 March.

Re: Subtropical rain North Island, from 5th Dec

Posted: Thu 06/12/2007 12:18
by jamie
We have only had 20mm here. and nothing in about the last hour.

Man what a horrible heat to work in though. it is just so muggy. At least its good for the thunderstorms 8)