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Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 12:46
by Tornado Tim
GreggWard wrote: Thanks for the explanation Tim. How would I go about trying to learn about this? Do you have any good web page references etc?
Jeff Habby has a whole Website about Meteorology, a really good resource: http://www.theweatherprediction.com/habyhints/
The NZ Meteorlogical Soc is another resource: http://www.metsoc.org.nz/ (To which I just became a member a month ago, honestly dont know why I waited so long)
Some American University's have powerpoints and other resources you can access for free too.

Some really good books on the weather that I use:
The NZ Weather Book by Eric Brenstrum
"Weather" by Burroughs, Crowder,Roberston,Valier-Talbot and Whitaker - This book I highly recommend if you can get your hand's on it- It made me a walking cloud dictionary :D

Forecast charts are great but they only capture one or two aspects of the Weather at a time. So if you want to analyse more data at a time, I would recommend to read up on Skew T charts, they are very powerfull and give a more full picture about what going on in the atmosphere.
Jeff Habby has whole section on Skew-T's and touches on the more advanced weather index's and how they should be used.
Hope that helps, if you want a bit more info I am sure Steven, myself and other members would like to help you out.


Gone mostly cloudy here at present, I dont expect anything to come from today.

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 12:49
by jamie
I'm not expecting much either. However I do see there have just been a couple of light showers develop around raglan. Maybe the start of things?

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 12:58
by NZstorm
A good area of rain coming down from the north so hopefully we all get some tonight.

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 12:59
by GreggWard
Tornado Tim wrote:
GreggWard wrote: Thanks for the explanation Tim. How would I go about trying to learn about this? Do you have any good web page references etc?
Jeff Habby has a whole Website about Meteorology, a really good resource: http://www.theweatherprediction.com/habyhints/
The NZ Meteorlogical Soc is another resource: http://www.metsoc.org.nz/ (To which I just became a member a month ago, honestly dont know why I waited so long)
Some American University's have powerpoints and other resources you can access for free too.

Some really good books on the weather that I use:
The NZ Weather Book by Eric Brenstrum
"Weather" by Burroughs, Crowder,Roberston,Valier-Talbot and Whitaker - This book I highly recommend if you can get your hand's on it- It made me a walking cloud dictionary :D

Forecast charts are great but they only capture one or two aspects of the Weather at a time. So if you want to analyse more data at a time, I would recommend to read up on Skew T charts, they are very powerfull and give a more full picture about what going on in the atmosphere.
Jeff Habby has whole section on Skew-T's and touches on the more advanced weather index's and how they should be used.
Hope that helps, if you want a bit more info I am sure Steven, myself and other members would like to help you out.


Gone mostly cloudy here at present, I dont expect anything to come from today.
Thank you very much Tim for all of the info.

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 13:05
by jamie
Looks like some convergence is getting underway up the west coast. Nice and close to here but can't see a thing due to all the cloud

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 13:46
by spwill
Yes, convergence shower line showing up west Waikato, isolated storm there
Some towering cumulus around Auckland now, overcaste and humid

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 14:35
by Manukau heads obs
the shower lines down the west coast here have developed very quickly
not a sea breeze convergence, more of a orograhic lift and slowing up of the wind down the west coast

you can see there is also orographic lift rain down the east coast of northland...ie the instability is such that it does not take much for shower activity

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 15:12
by Manukau heads obs
that shower line to the west of piha was explosive for develoment
its actually high based...more that it bored down from the top down

I can see the rain falling out to sea from here now..black as..as its lightning active

the clouds are building right over the coast line here too now...so I think we will get a good thunderstorm here soon...

I will be in waiuku though...young fellas touch rugby game

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 15:38
by spwill
Yes, a heavy shower line with thunderstorms has developed along the Auckland West Coast but just offshore going by radar

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 17:32
by David
Rain radar shows moderate rain over Howick for 40+ minutes, in reality there hasn't been enough to measure in the rain gauge yet 0_o

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 17:35
by jamie
David wrote:Rain radar shows moderate rain over Howick for 40+ minutes, in reality there hasn't been enough to measure in the rain gauge yet 0_o
Oh really? That's good..... Here I was thinking we were yet again missing out.

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 18:02
by NZstorm
Heavy shower here.

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 20:17
by NZstorm
That shower didn't give us a lot, about 2-3mm. Persistent light rain now.

Tim
Its because the upper air expected to be dry
That's one reason why a cap in good for thunderstorms, it helps protect the surface moisture from mixing upward into drier air.

The regions of the world that get severe thunderstorms have a strong capping inversion as part of the thunderstorm climatology, such as eastern Australia and USA. (loaded gun type sounding).

Re: Convective period. 26-28 Nov

Posted: Wed 27/11/2013 22:13
by mikestormchaser
Saturday night/sunday looked like a chance for us in Canterbury from when i checked the upper air was reasonable at -24.. not bad for summer anyways. wouldnt want it to cold.. but it seems thats also drifting offshore " sigh' :(

oh no.. just checked looking ok saturday afternoon actually..

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 00:15
by Michael
some rain here now,least the cooler weather this afternoon allowed the lawn to be mowed without the searing heat,the wind appears more southerly here now,can feel it in the window,southerly quarter winds tend to bring the most precipitation rather than NE.

Convective period. 26-28 Nov

Posted: Thu 28/11/2013 01:27
by jamie
Finally getting solid rain now. Very nice.

I also see MS have us on the boarder of a moderate risk for storms tomorrow. Maybe we can catch some more rain.

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 06:54
by NZstorm
Rain has been good but only 10mm here.

Today looks good for thunderstorms except for the quality of the low level convergence. Considering the time of year, thunderstorms will develop somewhere but pinpointing a good area? Waitomo could be ok.

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 06:54
by Manukau heads obs
you did well jamie I see, 25mm or so

15mm here in total
still raining a bit,...southerly wind...but rain bands moving down from the NW...

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 06:55
by Nev
We've had 34mm of very welcome steady light rain/drizzle here since about 3pm yesterday. :D

Convective period. 26-28 Nov

Posted: Thu 28/11/2013 07:10
by jamie
Yea did very well in the end. 28.2mm here. Makes me happier. Hopefully we can catch a storm too!

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 07:25
by David
We got 33mm in Howick, certainly more than I expected. Very pleasing!

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 07:35
by NZstorm
The east Auckland Hunua site on the Environment Waikato got 75mm!

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 07:38
by Manukau heads obs
sure hope those rain bands in the tasman rotate onto us today
but I have a feeling they might rotate over the top of us here and onto northland only
need another 10mm...that would be ideal,for us here....but cant complain too much :)

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 08:10
by spwill
This low has been a bit of a non performer for thunderstorms with the action being mostly offshore or over the central NI.
Good to have the rain :D and it has been warm.

Re: Convective period. 26-28 Nov

Posted: Thu 28/11/2013 08:30
by Manukau heads obs
westerly change arrived here now
you could see that on the rain radar , just to the north of that main rarin band out to the west

was a nice line of thunderstorms off the west coast here yesterday....shame it did not form a bit further east