Subtropic Interaction then Cold Change - 1st to 5th July

Archive of NZ Weather and Climate
Forum rules
These topics are a read-only archive and may be subject to out-of-date information.

For today's weather discussion head to: New Zealand Weather & Climate
User avatar
Tornado Tim
Moderator
Posts: 4920
Joined: Sun 19/10/2008 17:17
Location: Raglan, Waikato / Hillcrest, Hamilton
Has thanked: 102 times
Been thanked: 202 times
Contact:

Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Tornado Tim »

This month is going to be an interesting month for sure.

Esp the first half of this month, and this upcoming subtropic interaction coming in Wednesday.

Has a look at the 500 hpa Temp prognostics on the ECMWF model, the output is quite remarkable.

Typical Summer time upper air temps over most of the North Island(-10 C to -14), then mid winter ones coming into the South Island with a incoming polar shortwave (-30 C).

Setup's like this usually result in quite squally storms with very strong straight line winds on the leading edge of the cold change, so something to keep an eye out on later this week.
You do not have the required permissions to view the files attached to this post.
NZAPStrike.net - NZ Aus Pacific Strike Network
Bradley
Posts: 1516
Joined: Wed 01/05/2013 21:06
Location: Christchurch
Has thanked: 142 times
Been thanked: 269 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Bradley »

There was a few of those temperature differential cold fronts move through Canterbury this summer, quite spectacular and almost lost the trampoline over the neighbours fence in one of them!
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Cyclone Tracy »

EC's latest 18Z upgrading with more widespread heavy rainfall across the NI. Atmospheric river is running at 30 to 40mm on Thursday into Friday towards Coromandel and BOP. This map only goes out to Friday morning but you get the picture.
You do not have the required permissions to view the files attached to this post.
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

GFS showing almost no rainfall here for the next 7 days. EC showing around 40mm. Hard to tell how much we'll get...
Image
User avatar
NZstorm
Posts: 11333
Joined: Mon 10/03/2003 19:38
Location: Grey Lynn, Auckland
Has thanked: 342 times
Been thanked: 361 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by NZstorm »

All models agree on a deluge over the Bay of Plenty ranges, upto 250mm there. There are variations in rainfall amounts elsewhere but I think its a safe bet to say most parts of the North Island will catch some heavy rain tomorrow. Looks like some lightning possible upper Northland. And snow levels dropping over the Ruapehu region later tomorrow.
User avatar
Richard
Posts: 8369
Joined: Tue 14/07/2009 07:32
Location: Medbury, Inland North Canterbury
Has thanked: 1656 times
Been thanked: 800 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Richard »

Just a light skiff of snow for the SI by the looks of it.
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

GFS, EC and ACCESS-G all showing around 50mm for Auckland tomorrow. Would make it potentially the wettest day of the year so far.
Image
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

NZstorm wrote: Wed 03/07/2019 07:15 All models agree on a deluge over the Bay of Plenty ranges, upto 250mm there.
Just seen the BOP radar has gone offline for "urgent maintenance". Bad timing! Hopefully back before tomorrow? :-k
Image
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by tornado »

met service has a low risk for thunder in upper north island tomorrow but they could change it to moderate tonight.
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Cyclone Tracy »

MS now have the severe weather watch in place associated with the rainfall, snow and wind. https://www.metservice.com/warnings/sev ... ther-watch

Juicy atmospheric river now developing. It all comes down to where the convergence zone amplifies. Probably 50 to 80mm difference either side of the 100km wide subtropical waterslide during tomorrow. Looking forward to reviewing the 00Z runs this evening.
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Cyclone Tracy »

There is going to be some decent flash flooding around Auckland if that UKMet 00Z scenario plays out tomorrow afternoon. Big squeeze zone dropping 80mm to 100mm in a short period of time.
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by tornado »

maybe a rumble of thunder too.
NZ Thunderstorm Soc
Posts: 18488
Joined: Wed 12/03/2003 22:08
Location: Raukapuka Geraldine
Has thanked: 1769 times
Been thanked: 1412 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by NZ Thunderstorm Soc »

tornado wrote: Wed 03/07/2019 19:18 maybe a rumble of thunder too.
probably not but much needed rain to fill up the reservoirs that's needed in the auckland area.
JohnGaul
NZThS
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by tornado »

NZ Thunderstorm Soc wrote: Wed 03/07/2019 22:16
tornado wrote: Wed 03/07/2019 19:18 maybe a rumble of thunder too.
probably not but much needed rain to fill up the reservoirs that's needed in the auckland area.
true.
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

On 11mm so far, Metservice expecting another 60-80mm after 9am
Image
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Cyclone Tracy »

12mm already here.

Plenty if moisture appearing in the mid levels NW of Auckland above the convergence line at the moment.
You do not have the required permissions to view the files attached to this post.
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by tornado »

David wrote: Thu 04/07/2019 07:27 On 11mm so far, Metservice expecting another 60-80mm after 9am
if that heavy rain does fall it will stop the water crisis thats starting to happen
jamie
Posts: 5907
Joined: Fri 25/02/2011 21:35
Location: Hamilton NZ
Has thanked: 22 times
Been thanked: 273 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by jamie »

Bloody annoying that the BOP radar isn’t working.


Sent from my iPhone using Tapatalk
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

Was 16C all night. Unusually high for July
Image
jamie
Posts: 5907
Joined: Fri 25/02/2011 21:35
Location: Hamilton NZ
Has thanked: 22 times
Been thanked: 273 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by jamie »

David wrote:Was 16C all night. Unusually high for July
Very warm and humid. We are almost in the clouds. Cloud base about 20m? And rain. Very warm and humid too. Not like it’s a cold cloud base. This tells me conditions are ripe for a downpour.


Sent from my iPhone using Tapatalk
spwill
Posts: 9907
Joined: Sun 29/06/2003 22:39
Location: Mt Eden Auckland
Has thanked: 839 times
Been thanked: 866 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by spwill »

Cooler SW here now.
cbm
Posts: 1030
Joined: Fri 17/10/2008 08:50
Location: Cambridge, Waikato NZ
Has thanked: 13 times
Been thanked: 214 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by cbm »

S here now, gusting 50kms at the airport. A good 2 hours ahead of when the models had it arriving.
User avatar
David
Posts: 7578
Joined: Sat 18/08/2007 21:02
Location: Howick, Auckland
Has thanked: 416 times
Been thanked: 825 times
Contact:

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by David »

cbm wrote: Thu 04/07/2019 10:11 S here now, gusting 50kms at the airport. A good 2 hours ahead of when the models had it arriving.
Also noticed this, the direction change was earlier than I expected. Fairly solid rain here currently, up to 20mm since midnight.
Image
tornado
Posts: 1660
Joined: Sat 02/03/2019 21:58
Location: flat bush,botany,auckland
Has thanked: 81 times
Been thanked: 93 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by tornado »

It was 16 degrees Celsius. this morning and now its gone down to 13 degrees Celsius. yeah the rain is needed. hopefully its enough to stop the water crisis that they reckon is about to happen
Cyclone Tracy
Posts: 2488
Joined: Thu 07/09/2017 19:25
Location: North Shore, Auckland
Has thanked: 771 times
Been thanked: 1719 times

Re: Subtropic Interaction then Cold Change - 1st to 5th July

Unread post by Cyclone Tracy »

Just clocked 30mm here so far.
Locked