Another Low Pressure system for the weekend 2-3 August

[NZ Thunderstorm Soc]

Yes, well, the barometer is quite low, so anything could happen
Been steady here all day at about 988hPa
I had to hit mine with a hammer to try to make the needle move

JohnGaul
NZTS

[Peter]

I see this Sunday morning system as potentially having the best thunderstorms for Auckland but the Saturday front has potential.

What time is this Sunday system due? I'm flying out at 7:00am from Auckland Airport. 8o

[CHCH Weather Chaser]

Looking at the 7 day radar image for rain from metservice the loop is showing at 6pm saturday hitting the western areas of north island and auckland with a low of 979hpa and hitting parts of malborough midnight sat - into sunday. Here in christchurch we have not seen the sun in ten or so days and all day again its drizzled and rained with the latest bomb backtracking north towards us and stooling! Forecast tomorrow is for morning drizzle then FINE but rain returning again in the evening.

[NZstorm]

What time is this Sunday system due? I'm flying out at 7:00am from Auckland Airport.

It'll be nothing that will bother the airport. Some very squally showers/ts coming thru Sunday morn.

As for this evenings front, hopefully it can clear Auckland in time for kick off.

[Michael]

These are the Wet Winters I mention a lot in the mid 1980s through the early 90s especially probably noticing it from Wanganui where yes they had wet spells but they only were short but not months like here.

[Nev]

Mark, can I just remind you that what you're looking at is not a "7 day radar image", but rather a '7 day forecast model' of predicted accumulated rainfall.

And as for "the latest bomb", we've only had one 'weather-bomb' and that was on Saturday, i.e a pressure drop of at least 24 hPh within a 24 hour period, which is an extremely rare event for NZ.

[Manukau heads obs]

and thats the pressure in the center of the low too....not your own pressure (which would have started higher)

[Manukau heads obs]

new system thats a coming is lightning active, my boltec picking up the strikes nicely
CB's popping up in the cloud sheet
the sky this morning, with that unstable looking alto cumulus, looked ominious to me...its developing quickly this new system and the whole situation is very dynamic

[Vertigo]

yes, it is!

[Philip Duncan]

These are the Wet Winters I mention a lot in the mid 1980s through the early 90s especially probably noticing it from Wanganui where yes they had wet spells but they only were short but not months like here.

I wish I could find the quote where someone RIPPED me down for going against NIWA saying back in March that I thought this winter would end up becoming a wet one - even made specific mentions on TV to people in northern facing regions to be prepared to to go from droughts to flooding this winter. I don't usually gloat but this person was so rude to me I feel the need to mention it here!

[Manukau heads obs]

yes, also a number of us here also posted that the warm tasman sea over the autumn could result in lots of thunderstorms in june/july

[Philip Duncan]

Yeah it just seemed so obvious! I'm not a huge fan of long range forecasting - well, not for 2 small islands in the south pacific and in the roaring 40s. But even I figured warmer waters usually equals wetter weather - certainly in winter when the air pressure is lower more often.

[Manukau heads obs]

sever thunderstorm watch out from M/S
http://www.metservice.co.nz/default/ind ... stormwatch

[Peter]

that's a very wide area for the severe watch, and quite strong wording - feel like I'm back on the Plains on a "Low Risk" day!

[Michael]

Not quite about today,but the dry 1946 year ended up wet in winter and recently 1998 was another dry/hot summer and remember the floods.

[tgsnoopy]

It's going to be an interesting evening with a little luck.

Metservices Severe Thunderstorm Watch


I like the outlook:

Severe Convection/ Thunderstorm Outlook
Valid to: 00:00 am 3 Aug 2008 NZST
Issued at: 9:12 am 2 Aug 2008 NZST

A low is currently deepening in the central Tasman Sea and it is expected to cross central New Zealand tonight. The associated cold front looks to be quite active as it crosses the North Island this afternoon and evening with very strong northerlies ahead of it and strong northwesterlies in behind.Thunderstorms are expected along the cold front, which may take on squall line characteristics as it crosses the upper North Island.

CHART AND DISCUSSION AMENDED TO INCLUDE NORTH TARANAKI... There is a moderate risk severe thunderstorms affecting areas from Northland to North Taranaki later this afternoon, and the Coromandel Peninsula and Bay of Plenty this evening. The fast moving nature of these thunderstorms gives rise to potential wind gusts of over 110km/hr (they could reach 130km/hr) and there is a real risk of damaging tornados in the vinity of the front, especially in coastal areas. Rainfall rates should be somewhat limited the mobility and are likely to fall into the 10-25mm/hr category.

Then following in behind the front more fast moving thunderstorms are expected in the northwesterly flow, and these should move into areas from Gisborne to the central plateau to Taranaki and then Manawatu, squeeze through the Gorge into northern Wairarapa, and then across the Kapiti Coast, northern Marlborough and Nelson this evening. These thunderstorms have the potential to give wind gusts in the 90-110km/hr range, rainfall rates of 10-15mm/hr. In addition, there is a risk of a weak tornado over the remainder of Taranaki and northwest of the central plateau in the afternoon as the cold front passes there (the potential is judged to be somewhat less than the area already mentioned further north.

Please refer to www.metservice.com for details of watches and warnings in effect.

There is a low risk of some spill over thunderstorms in the east of the North Island this evening, but otherwise no thunderstorms or significant convection is expected elsewhere

[Nev]

I wish I could find the quote where someone RIPPED me down for going against NIWA saying back in March that I thought this winter would end up becoming a wet one - even made specific mentions on TV to people in northern facing regions to be prepared to to go from droughts to flooding this winter. I don't usually gloat but this person was so rude to me I feel the need to mention it here!

Umm, we've still got one month to go yet. According to NIWA, May was a cold month, with the national average temperature being 1.1°C below average. In terms of extremes, it was a very quiet month, with few high intensity rainfall events. Winds were also much lighter than normal in many areas. Anticyclones dominated the weather patterns. Above average sunshine hours occurred in the west of both islands and inland areas of the South Island. Only in the east of the North Island were sunshine totals well below average. Sunshine was well above normal in Auckland and Hamilton recorded their 2nd highest ever, while in the other 3 main centres sunshine was near normal. Rainfall was also either near or below normal in the 5 main centres.

[David]

What has May got to do with Phillip Duncan predicting a wet winter?

[Nev]

Sorry, my bad! Got my months mixed up

[Philip Duncan]

lol

[Manukau heads obs]

seems to me that the CB activity on this approaching cold front is sporadic
its going to be a hit or miss for any one place me thinks

[Philip Duncan]

Do you think the Severe Thunderstorm warning is a bit OTT?

[Manukau heads obs]

at the moment I cant see anything out of the ordinary happening
but things could change as the front gets more organised as it gets closer

the lightning activity has faded away from what it was first thing this morning too

[NZstorm]

Severe Thunderstorm warning is a bit OTT?

Its a Severe Thunderstorm Watch Philip, not a warning. Two entirely different things. A watch indicates the chance of severe weather occuring, a warning means the severe weather is happening.

[jamie]

I think this could easily be a no show... but yet again it could be good.. could make the test an interesting one tonight.

Lightning has definitly slowed but it could just be recycling itself and about to become more active again as these sort of fronts usually do.