Westerlies to return with a vengeance next week

September 28, 2016

After more than a week of east to northeast winds affecting the country, you might be wondering where the normally westerly winds of Spring have gone.

In the past week, persistent northeasterlies have brought flooding rains to Auckland, the Coromandel Peninsula and Gisborne. A Severe Weather Warning and Watch remain in force for further heavy rain expected to affect the northeast of the North Island through to Thursday. Meanwhile, West Coasters have been enjoying a relatively fine and dry period of weather. 
“Milford Sound, which averages around 550mm of rain during September, has received less than half that amount so far this month, and only 2mm has fallen there in the past 10 days,” said MetService meteorologist Peter Little.
After this unusual hiatus, caused by a blocking high camping east of the country, the equinoctial gales we usually associate with Spring weather are poised to return next week. 
“We enter a transition period this weekend as the blocking high begins to weaken and move away to the east,” said Mr Little. “This will allow our weather to start moving in a more typical west-to-east fashion again, and by the looks of the long range models the westerlies will be the dominant weather driver for the first half of October,” he added.
On Friday MetService releases its latest rural monthly outlook, reviewing the past month’s weather and looking ahead to what October will bring. You can sign up to receive these monthly outlooks by email here: Monthly Outlook Email.

Forecast surface pressure and winds for 1pm today and 1pm next Wednesday, based on ECMWF model data. This shows the dramatic change to strong westerlies across the Tasman Sea and New Zealand by the middle of next week .

Official Severe Weather Watches and Warnings are reviewed and re-issued by MetService at least every twelve hours, and more often if necessary. To get the most up to date information on severe weather around the country, or any other forecasts, see metservice.com or on mobile devices at m.metservice.com. You can also follow our updates on MetService TV, at MetService New Zealand on Facebook, @metservice and @MetServiceWARN on Twitter and at blog.metservice.com 

MetService issues Warnings, Watches and Outlooks for severe weather over New Zealand. 

Warnings are about taking action when severe weather is imminent or is occurring. They are issued only when required.
Recommendation: ACT 

Watches are about being alert when severe weather is possible, but not sufficiently imminent or certain for a Warning to be issued. They are issued only when required.
Recommendation: BE READY 

Outlooks are about looking ahead, providing advance information on possible future Watches and/or Warnings. They are issued routinely once or twice a day.
Recommendation: PLAN 

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