From low to snow, with a bit of a blow

September 4, 2016

A deep low situated west of the South Island is set to track across southern New Zealand tonight, bringing gale force winds and heavy rain to much of the country.  The heaviest rain is expected around southern Westland and alpine regions of Canterbury south of Arthur’s Pass, where 120 to 180mm of rain could accumulate by early Monday morning.  Gales with gusts around 100kph are expected in exposed parts of central and southern New Zealand, already kicking off in the far south this morning with 93kph gusts recorded in the Dunedin hills.  These winds work north, affecting Canterbury later this morning, Marlborough this evening and Wellington and Wairarapa tonight.

On Monday morning the northerlies ease off down south, but are soon replaced by a strong southerly. It will be a gusty morning in the capital too, where the strong northerlies won’t take a break until the afternoon.  The southerly flick in the south will bring the temperature down, but is only a precursor for strong southerly change expected late Wednesday or early Thursday.

“We are currently expecting a strong ‘southerly buster’ to come through around mid-week” said MetService meteorologist Tom Adams. “This fast moving front will bring southwesterly gales, colder temperatures and even the chance of some spring snow down south”. Farmers with young livestock should be aware of a few frosty nights at the end of the week. “The strong winds won’t be long-lived”, said Mr Adams, “as it is followed up by a ridge bringing cool but settled weather into the weekend, but it will be a reminder that in the spring the weather can change in an instant”.

2016-09-04

This image contrasts the origins of the warm air from the Tasman spreading over New Zealand today, and the colder Antarctic air we can expect on Thursday.  Images produced using NOAA’s HYSPLIT and Google Earth.

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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