Thunder possible this week starting 13th Feb

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NZstorm
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Thunder possible this week starting 13th Feb

Unread post by NZstorm »

Looking like thundery possibilities this week with that upper trough slowly crossing(500mb-17C) and moist airmass (dp16-17C). Daytime heating will be important, looking like temps of 23C-24C will be warm enough for deep layer CAPE.

Today Monday could see an isolated convergence cb pop up over inland Bay of Plenty if the cloud can break up enough for heating to occur.

Tuesday could see daytime heating activating a front over the NI and also over inland South Island ranges with thunder/isolated hail.
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Re: Thunder possible this week starting 13th Feb

Unread post by spwill »

Keeping an eye on Thurs/Fri for possible chase days, dp 17-18C, upper level trough, day time heating and west coast sea breeze convergence.
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Re: Thunder possible this week starting 13th Feb

Unread post by jamie »

hmm yes latest GFS does look very nice for thursday friday.
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Re: Thunder possible this week starting 13th Feb

Unread post by Tornado Tim »

Isolated CB developed on the trough around Paeroa this afternoon/early evening. It has now backed off as it surged out east a little.
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Re: Thunder possible this week starting 13th Feb

Unread post by spwill »

Towering cumulus over Auckland
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Re: Thunder possible this week starting 13th Feb

Unread post by NZstorm »

Some lightning over East Cape this morning.
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Re: Thunder possible this week starting 13th Feb

Unread post by Tornado Tim »

I am surprised Metservice has upgraded the risk to High this morning, looks like more of a moderate setup to me.
Shower activity is expected to become wide spread over the North Island this afternoon and evening being set off by a front which will move onto western areas this afternoon and in areas further east by afternoon wind convergences and daytime heating.

In the far northeast of Bay of Plenty and north of Gisborne, a persistent area of very heavy showers delivering 30 to 50mm/hr in places this morning. This is gradually weakening and is expected to have dissipated by noon today.

There is a high risk of thunderstorms from Manawatu to Taranaki to central Hawkes Bay northwestwards starting in Taranaki this morning and then spreading further east this afternoon. Elsewhere north of about Wellington, there is a moderate risk of thunderstorms which if triggered, will drift out to the east coast in the evening. With all of these thunderstorms, there is the potential for rainfall rates up to 25mm/hr but higher rates are possible in pockets where storm dally. Finally, there is a low risk of thunderstorms over the upper South Island this afternoon and evening.

Elsewhere, no thunderstorms or significant convection is expected.
Just had a look some model runs and it seems the atmosphere is only partially unstable with only some areas getting a slightly lower LI of -1, Northern to central Waikato: 0 to -0.5.
The Warm front will have to be the trigger ontop of DTSH for this setup to pan out, or another form of a trigger such as SB front.
A 500mb temp of -14 to -15°C means there will have to be a good SFC temp to get decent convection.

Outlook courtesy of M/S
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Re: Thunder possible this week starting 13th Feb

Unread post by spwill »

The radar shows some heavy showers along the Front currently.

20C, dp 18C here, sunshine through high cloud.
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Re: Thunder possible this week starting 13th Feb

Unread post by David »

Quite a nice day here so far, 22°C, light NE'er, mostly cloudy but bright conditions with sunny spells. Some heating before the front is good! And the DP here is 17-18C too
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Re: Thunder possible this week starting 13th Feb

Unread post by Thunder »

Nice photos Spwill, will keep an eye on here :)

EDIT: Aaron J Wilkinson sounded lame, Stormchaser from now on.
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Re: Thunder possible this week starting 13th Feb

Unread post by Tornado Tim »

Gone completely cloudy temp around 23°C atm, some showers around but they are featureless atm.
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Re: Thunder possible this week starting 13th Feb

Unread post by spwill »

24C/dp20C, cloud/sunshine mix. Some weak showers crossed the City early-mid afternoon.
Aaron J Wilkinson sounded lame, Stormchaser from now on
We just need a few storms now Aaron. :smile:
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Re: Thunder possible this week starting 13th Feb

Unread post by Manukau heads obs »

I said to Ricky this morning the sky looked pretty stable...
only a realtively weak shower line here went through..but nice total of rain all the same...
no lightning detected...
maybe next days ahead more action?
a cut off low usuaaly delivers!
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Re: Thunder possible this week starting 13th Feb

Unread post by spwill »

There has been better development on the Front east of here.
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Re: Thunder possible this week starting 13th Feb

Unread post by jamie »

got a mushroom cloud from the fast passed lift occuring to my east. hasnt reached the roof of the atmosphere yet though.
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Re: Thunder possible this week starting 13th Feb

Unread post by Tornado Tim »

Ouch I can feel the sting metservice will feel after this, a High risk bust!
I personally didnt know why they put out a High Risk in the first place, perhaps they knew something we didnt.

The air around here is mixing out quite a bit and convection as a result simply flops.....
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Re: Thunder possible this week starting 13th Feb

Unread post by Philip Duncan »

I wonder if they're a little shorter on staff today? As that thunder risk didn't change from just before 9am and their forecast for Auckland hasn't changed since yesterday - still says showers, turning to rain some thundery. Unless the cache on my computer isn't working!?

Glad we publicly lowered our risk for thunder to low for Auckland and moderate for Waikato this morning. But we still thought there would be more rain than what turned up. Seems to be a pattern with these weak west coast lows over the past few years.
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Re: Thunder possible this week starting 13th Feb

Unread post by jamie »

anyone car to punt on how thursday friday will be? friday to me looks the better day but im no good at forecasting
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Re: Thunder possible this week starting 13th Feb

Unread post by Michael »

Could see 4 cbs clear at 7pm but now have clouded over
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Re: Thunder possible this week starting 13th Feb

Unread post by Manukau heads obs »

looking a bit more unstable out to my SW now
maybe it was a bit later coming in than expected?
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Re: Thunder possible this week starting 13th Feb

Unread post by NZstorm »

anyone car to punt on how thursday friday will be? friday to me looks the better day but im no good at forecasting
Both OOZ GFS and ECMRF still have an upper level trough over the North Island Thursday/Friday so storms still on the cards.
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Re: Thunder possible this week starting 13th Feb

Unread post by NZstorm »

looking a bit more unstable out to my SW now
maybe it was a bit later coming in than expected?
The front is just north of us now. It may activate a bit overnight over Northland with isolated elevated storms.
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Re: Thunder possible this week starting 13th Feb

Unread post by Nev »

Tornado Tim wrote:Ouch I can feel the sting metservice will feel after this, a High risk bust!
I personally didnt know why they put out a High Risk in the first place, perhaps they knew something we didnt.

The air around here is mixing out quite a bit and convection as a result simply flops.....
Jim reported earlier tonight that T-Storms were firing up over inland North Island and the West Coast and that T-Storms were affecting areas around Whangaarei, Rotorua, Taranaki and Mahia.

Also, New Plymouth recorded 45mm in 2 hours today and Hicks Bay recorded 130mm in the early hours of this morn.
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Re: Thunder possible this week starting 13th Feb

Unread post by NZstorm »

Hicks Bay recorded 130mm in the early hours of this morn.
Thats an interesting ob.
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Re: Thunder possible this week starting 13th Feb

Unread post by Tornado Tim »

Nev wrote: Jim reported earlier tonight that T-Storms were firing up over inland North Island and the West Coast and that T-Storms were affecting areas around Whangaarei, Rotorua, Taranaki and Mahia.
West coast had a few storms throughout the day but Rotorua as far as I was aware only had heavy showers and possibly the odd rumble of thunder, hardly what I would call a thunderstorm, perhaps what the Americans usually term it a "thundershower" instead.

I can see from the GPATS Lightning archive (via Weatherzone AU) there was hardly any lightning at all today.
Metserivce now has a Severe Thunderstorm Watch Out for Northland now.
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