Heavy rainfall South Island west coast, October 8th-12th

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Chris W
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Heavy rainfall South Island west coast, October 8th-12th

Unread post by Chris W »

An extended few days of heavy norwest rainfall is on the cards from today through to the weekend for the coast, Metservice warnings projecting 450-650mm for the ranges and 200-300mm for the coast to the end of Thursday with 250-350mm spillover rain into the Canterbury high country. More rain through the weekend but low confidence of warnings for the weekend at this stage. It's the coast yes, but MS are calling it a significant fall so I thought it worth a thread.

https://www.metservice.com/warnings/sev ... r-warnings
Last edited by Chris W on Tue 08/10/2019 11:19, edited 1 time in total.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Razor »

Some startling numbers from Metservice for Franz Josef. If its that much on the low lying land I can only imagine closer to the divide, and what follows Thursday through the weekend could make this look like the March event all over again
franz.jpg
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Cyclone Tracy »

Cloud tops on the Tasman storms are hitting -65c as the cold pool starts to interacts with the sub-tropical moisture.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by NZ Thunderstorm Soc »

Cyclone Tracy wrote: Tue 08/10/2019 15:48 Cloud tops on the Tasman storms are hitting -65c as the cold pool starts to interacts with the sub-tropical moisture.
Should be a lot of storms then?
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Cyclone Tracy »

NZ Thunderstorm Soc wrote: Tue 08/10/2019 16:18
Cyclone Tracy wrote: Tue 08/10/2019 15:48 Cloud tops on the Tasman storms are hitting -65c as the cold pool starts to interacts with the sub-tropical moisture.
Should be a lot of storms then?
Only in the Tasman in my opinion. Cold air aloft will warm as its cut off from the westerly flow. Plenty of rain though :smile:
Chris W
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Chris W »

GFS only has 500mb temperatures up to about -22ish, so if that's correct turn the air aloft is a bit warm. Very moist though.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by tich »

The main rivers in east of SI should consequently rise significantly.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Chris W »

They were showing some signs this morning of doing so, but even in the March event this year the Waimak stayed within its banks.

The Waiho will be giving the new bridge a good test.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Razor »

Chris W wrote: Wed 09/10/2019 15:11 They were showing some signs this morning of doing so, but even in the March event this year the Waimak stayed within its banks.

The Waiho will be giving the new bridge a good test.
Waiho is the one rain gauge thats offline with the West Coast Regional Council at present. A few sites have tipped out 200mm+ so far and I see West Coast Civil Defence has opened an ops centre
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Razor »

Looking at the WCRC gauges several sites have popped past 250-300mm for the event so far, not out of the norm for West Coast, it seems the worst has failed to eventuate, touch wood
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Chris W »

Yes it seems it hasn't been as bad as it could have been, great news.
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by melja »

To be fair MS did note this in there updated weather warnings.

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Chris W
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Re: Heavy rainfall South Island west coast, October 8th-12th

Unread post by Chris W »

Yes, no criticism of MS at all. They did a great job of warning and then updating.
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