Severe Weather Outlook through to Saturday 12th October

[JennyLeez]

Issued: 2:34pm Monday 7 Oct 2013 by the Metservice
Valid from Wednesday 9 October 2013 to Saturday 12 October 2013

The low should cross central New Zealand during Wednesday, and rain is expected to spread to most of the North Island, with gale southerlies about Wellington and south Wairarapa, and gale westerlies about Northland. There is a moderate confidence that the southerlies could reach severe gale about Wellington on Wednesday, but a low confidence that gale westerlies about Northland could reach severe gale.

On Thursday, a front is expected to move quickly over the country, followed by a low late Friday to early Saturday. However, at this stage there is some uncertainty as to the position and track of the low on Saturday. A strong to gale west to northwest flow precedes these two features, with rain expected about most western areas. There is a low confidence of heavy rain about Fiordland on Thursday, with a moderate confidence of severe northwest gales about Wairarapa and central Hawkes Bay on Thursday and Friday. There is then a moderate confidence of severe northwest gales about northern Hawkes Bay and Gisborne from Friday to Saturday, with a low confidence of severe westerly gales about Northland, Auckland and the Coromandel Peninsula on Saturday.

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[TokWW]

An image from MetVUW shows the very deep LOW over the South Island on Saturday with gale to storm force westerlies over most of the North Island.  Now this forecast was run on Monday so it is 5 days out and possibly likely to change in intensity and location over that period.  This will need watching as it has the capability to do some damage!

[JennyLeez]

Update from the Metservice:         

A low should cross the North Island on Wednesday. There are various warnings and watches for this event that should be over by Wednesday evening.

On Thursday a cold front should move onto the South Island while a strong mild westerly flow spreads over the North Island. A brief period of heavy rain is likely in Westland and Fiordland but amounts will probably stay below warning levels.

During Friday a very strong northwest flow is expected to develop over the North Island as an active front approaches and a deepening low crosses central New Zealand. A low risk of severe northwest gales is shown for all the North Island during Friday and Saturday morning, with the most likely area being Hawkes Bay and Gisborne where a moderate risk is indicated. This low and front will also bring rain to most of New Zealand with a low risk of heavy falls shown for western North Island areas from Waikato to Manawatu, and also western Nelson. Buller, and northern Westland. On Saturday a strong southwest flow should spread over New Zealand with rain easing and gales abating. During Sunday another strong northwest flow spreads onto the South Island with more rain for Westland and Fiordland.

         
From Weatherwatch:
7 days of windier weather about to roar in -
Some haven't had much of a break from the strong spring winds so far this October, while others have finally been able to enjoy calm conditions and mostly sunny skies.
But on Friday the predicted windier change will arrive - marking a week ahead of sometimes intense winds and possibly signalling a mostly windy change up until Labour Weekend.
Head weather analyst Philip Duncan says this is spring peaking.  "October is traditionally when spring peaks with strong winds, thunderstorms and some hot weather finally moving in to some regions.  This windier change , which starts this Friday, is simply the peak spring winds pushing through".
Mr Duncan says a large low around Antarctica and a big high north of us puts New Zealand "smack bang in the squash zone, where the winds are strongest".
"The Roaring Forties are going to race up and roar over New Zealand for at least the next week or two".
To add fuel to the windy weather the Southern Alps, the eastern North Island ranges and Cook Strait region all work to create a funnel effect, pushing up wind speeds even more for central New Zealand and eastern areas of both islands.
However at this stage WeatherWatch.co.nz does not see a repeat of the Canterybury wind storm last month.
Also,. the windier weather can being spectacular sunny skies to eastern and north eastern areas, like Bay of Plenty, Gisborne, Marlborough, Canterbury etc.
This windy spell will likely finally start to dry soil conditions in many eastern and northern areas too.
Winds should take a bit of breather around next weekend - but central and southern areas may still have a brisk wind lingering.

[TokWW]

Saturday at 01:00 (1am) is showing the strongest action from this nasty little deep depression with a centre below 980hPa with 40knot westerly winds (80km/hr) south of new Plymouth to 35kt sou-westers north of Hokitika = 70km/hr.  There will be storm damage.  The rain may not be as heavy as first thought in the North island, but the gale force easterlies on the east Coast of the South Island will have very heavy overnight falls - Friday night.  Eastern rivers will rise quickly. 

During Saturday, the Low moves off to the East fairly quickly and the winds will abate and turn sou-westerly over the whole of NZ.