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Storms Possible - 24 September
Posted: Wed 23/09/2015 21:17
by Tornado Tim
Interesting how the Metservice increased the risk of a Storm over Auckland in this evenings update:
Updated withe the target area for thunderstorms moved over Auckland and northern Waikato...
Cold temperatures aloft and afternoon heating are expected to produce showers over the North Island on Thursday afternoon and evening. There is a moderate risk of thunderstorms developing over northern Waikato and Auckland tomorrow afternoon, clearing in the evening. These thunderstorms have the potential to produce hail in the 10 to 20mm range and rainfall rates of 10 to 25+mm/hr. The highest rainfall intensities are most likely over the Auckland area due to slow storm motions. In addition, there is also a risk of significant localised hail accumulations. These conditions would make driving difficult and may cause localised flash flooding.
The risk of thunderstorms is lower in a surrounding area including Waitomo to Bay of Plenty and eastern parts of Northland.
Elsewhere, no thunderstorms or significant convection expected.
Most like due the sfc trough forecast to be further north and SFC dps being a bit higher than more inland.
Re: Storms Possible - 24 September
Posted: Wed 23/09/2015 21:39
by NZstorm
The last couple of runs of the gfs has pushed the moisture convergence northward to lie over the Auckland region.
Overall looking like a borderline set up but hoping for an improved outlook in the overnight modelling.
Re: Storms Possible - 24 September
Posted: Wed 23/09/2015 21:56
by spwill
See what the cloud cover is like tomorrow, our weather has been underperforming for sunshine lately.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 07:21
by NZstorm
The moisture is right today with moist air at the surface and dry aloft. Big tick there. GFS indicates convergence still on the cards for the Waikato and also around Auckland up to Whangarei. There is good upper easterly flow over the Waikato so any development will quickly move into the west. Auckland north should see slow motions with lighter winds aloft. Localised heavy falls/small hail possible.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 07:35
by Manukau heads obs
wind has died here again...this morning..from the SW
so a bit of a repeat setup to Tuesday in that regard
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 08:12
by Manukau heads obs
wind shifted SE here now...good sign
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 08:42
by Tornado Tim
The 12Z run of the GFS has moisture back in further South over central Waikato. Today could be interesting. Will watch the radar with interest
Would like to see the Whenuapai Sounding......
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 08:44
by Tornado Tim
This Morning's T-storm Outlook, even more north:
Metservice wrote:Cold temperatures aloft and daytime heating are expected to produce showers over northern parts of the North Island, with a broad low risk of isolated thunderstorms from Waitomo and Bay of Plenty northwards, as indicated on the chart. However, this risk of thunderstorms is considered nearer moderate over northern Waikato and Auckland this afternoon and early evening. Any thunderstorms that eventuate have the potential to produce localised heavy rain of 10 to 25mm per hour and hail of 5 to 15mm in diameter.
Elsewhere, no thunderstorms or significant convection expected.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 09:02
by Manukau heads obs
temperature climbing with some sunshine here
Storms Possible - 24 September
Posted: Thu 24/09/2015 09:25
by jamie
Not great here with light shower at the moment
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 09:37
by Tornado Tim
jamie wrote:Not great here with light shower at the moment
Yea Looking at the Radar, a few more will have come through yet. Hopefully they fizzle fast, otherwise we will get Tuesday occurring again.
Need that temp to climb.....
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 10:17
by David
Unfortunately it's a rather dull cloudy day here in central Auckland
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:31
by shovelopikis
Activity will be more south I reckon, judging by current outdoor obs it's 17c with on off cool showers, hot sun....we had hail showers the other day, this one might produce something......I hope.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:34
by treetop
Thunderstorms over Mamakus heading Hamilton way intensifying now . Looks good for West Waikato. Will be hail too. Happy chasing !
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:39
by Manukau heads obs
that early warming caused early cloud build ups (was impressive bases on them)...and it cooled down again...sunny spells again now here...so it might have another go at it
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:40
by Tornado Tim
Yup fair bit of Lightning going on in central Waikato atm
Heading west
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:46
by Tornado Tim
Up to 18 so far in Matangi, nice
Initiated very early.......
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:47
by David
Weather has fined up nicely now, I see it's currently 18C with dewpoint 13C in Howick.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 12:51
by Manukau heads obs
we actually have a light sea breeze here...so things could get interesting later...or not...
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 13:10
by Tornado Tim
Manukau heads obs wrote:we actually have a light sea breeze here...so things could get interesting later...or not...
I love how pessimistic we have become
......... LOL
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 13:56
by shovelopikis
Few rumbles here's, dark cloud bases with heaps of Sun in between on a balmy 18c now.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 14:20
by NZstorm
3pm convergence chart from gfs. The southern Waikato convergence shows up well.
Perhaps some convergence over Auckland as well but the NZWP midday sounding shows some CIN aloft.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 14:23
by NZstorm
NZWP sounding from today. A warm nose at 700mb.
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 14:37
by Tornado Tim
Some Thunder to the North of Raglan
Re: Storms Possible - 24 September
Posted: Thu 24/09/2015 15:10
by Nev
Pic of a funnel-cloud over Hamilton airport this arvo posted on
Civil Defence Waikato's Facebook-page…