General July Weather

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Richard
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Re: General July Weather

Unread post by Richard »

Yep neat photo alright.

Thick heavy fog here this morning which has helped keep the frost away.
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Re: General July Weather

Unread post by snowchaser01 »

Now that this event is mostly over in terms of snow fall, we can start talking about late next week, which has been in the models for a few days now. A possible advection element in there too. Could be interesting for sure.
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Re: General July Weather

Unread post by NZ Thunderstorm Soc »

Yes, could be. Have to wait to see how the models pan out for this :P
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Re: General July Weather

Unread post by Bradley »

GFS likes it more then EC at this stage - a good sign as EC so far this winter has been performing badly compared to past seasons!
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Re: General July Weather

Unread post by Dean. »

Bradley wrote:GFS likes it more then EC at this stage - a good sign as EC so far this winter has been performing badly compared to past seasons!
Agree...Metvuw (GFS) very accurate for this region all year
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Re: General July Weather

Unread post by NZ Thunderstorm Soc »

Good. :smile:
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Re: General July Weather

Unread post by Razor »

Yes, GFS has been looking promising next week for some for a few days now. Time will tell, lets see what it looks like come Monday
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Re: General July Weather

Unread post by mikestormchaser »

I'm not 100% sure on the numbers for warm advection events but it looks quite warm. I know warm advection is different and the models dont pick it all up. But it still does look warm this far out
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Re: General July Weather

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mikestormchaser wrote:I'm not 100% sure on the numbers for warm advection events but it looks quite warm. I know warm advection is different and the models dont pick it all up. But it still does look warm this far out
Things like thickness and the upper temps don't really hold much value when it comes to advection. Its all about cold air undercutting warmer air, and the heavy precip that the warm air brings lowers the freezing level.
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Re: General July Weather

Unread post by spwill »

I think with the warm advection low level snow ( approaching north Tasman low) you still want to see at least quite cold air in the model, residue chilled air in the inland valleys helps a lot as well.
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Re: General July Weather

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spwill wrote:I think with the warm advection low level snow ( approaching north Tasman low) you still want to see at least quite cold air in the model, residue chilled air in the inland valleys helps a lot as well.
The warm advection snow in Tekapo earlier this month had 850mb temperatures around 0C in the modelling and snow fell to 700m.
A big snow dump in Southland on 24th July last year occurred with 850mb temps -2 to -3C and snow fell to 100m. This gives a rough idea of what temperatures to look for in warm advection snow forecasting. And yes, a severe frost in the valleys helps.
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Re: General July Weather

Unread post by Bradley »

Yes and the big one in Canterbury in June 2015 had 40cm of snow to 300m ask and 10cm right down to 150m with 850hpa temps of only -2C
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Re: General July Weather

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Definately something big and nasty brewing for Thursday next week - knowing the unpredictability of these low pressure systems though it could just as easily end up hitting the North Island instead #-o
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Re: General July Weather

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GFS has backed off big time this morning. If only we could get just one decent saturating weather system. :mad:
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Re: General July Weather

Unread post by einzack »

Currently cloudy and -1.6°C.
Decent frost, with low of -2.5°C but it clouded over quite quickly now so could be a rather miserable day.
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Re: General July Weather

Unread post by einzack »

It's actually started drizzling and it's still -1.6°C.
Went outside to get some wood and yeah, got a little bit wet and still well below zero.
Not sure I've ever experienced that before.
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Re: General July Weather

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Bradley wrote:Definately something big and nasty brewing for Thursday next week - knowing the unpredictability of these low pressure systems though it could just as easily end up hitting the North Island instead #-o
Yes, another cold southerly blast seems locked in, but only brief, and not as cold as the last one.
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Re: General July Weather

Unread post by Razor »

Looks interesting Thursday/ Friday!

Considerable uncertainty I know, but if this comes off...it'll be an interesting end to the school hols
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Re: General July Weather

Unread post by Bradley »

Yes a couple of key elements of this event such as precipitation, 850hpa temps and thickness levels remind me of the 12th June 2006 event, if anything this could be even nastier! As we know though the position of these low pressure systems are notoriously hard to predict. For reference below is the meteogram from the night before the 2006 event and also the latest meteogram for Friday:
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Re: General July Weather

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Strong wind possible with the system late week.
Currently the gfs is going for severe gales in exposed areas for the North Island with Thursdays front. Auckland area could see big gusts.
And severe gales for eastern South Island Friday. Just model output at this stage and not a forecast.
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Re: General July Weather

Unread post by NZ Thunderstorm Soc »

I'd like to know where tomorrow's heavy rain is coming from tomorrow?
Over 20mm for Timaru forecasted.
Looks like a forecast for Hamilton or Auckland. o_O
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Re: General July Weather

Unread post by Plato »

Mt Cook Village has been awfully cold so far this month. Average high of 3C and an average low of -7C (July normals are 6.5C/-2C). July 7th was the coldest day, at -3C/-12C (though yesterday was close, at -2C/12C).
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Re: General July Weather

Unread post by spwill »

Plato wrote:Mt Cook Village has been awfully cold so far this month. Average high of 3C and an average low of -7C (July normals are 6.5C/-2C). July 7th was the coldest day, at -3C/-12C (though yesterday was close, at -2C/12C).
The higher parts of the Mackenzie can be bitter in Winter including Tekapo and Twizel.
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Re: General July Weather

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NZ Thunderstorm Soc wrote:I'd like to know where tomorrow's heavy rain is coming from tomorrow?
Over 20mm for Timaru forecasted.
Looks like a forecast for Hamilton or Auckland. o_O
Coming down heavy here near Pleasant point for the last couple of hours, 10mm in the gauge. if it keeps up for another couple of hours wont be far off the 20mm forecast.
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Re: General July Weather

Unread post by NZ Thunderstorm Soc »

Yes, interesting. Been raining here since this morning from the north.
Looks dark towards the Point but is clearing to the north. 4.3mm so far here for today.
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