Wicked southerly bringing snow and swells from Wednesday

September 5, 2016

While much of the country woke up to windy and showery conditions to start the week, it is Wednesday when things will really deteriorate. Strong southwesterlies over New Zealand are the hangover from a busy weather weekend, but the frontal system which brought significant rain is now moving away from the country. The southwest flow will ease over the next few days, making Tuesday the pick of the week with afternoon fine spells on the cards for all the major centres.

The entire regime will change on Wednesday when a potent cold front races up the country. This front will spearhead a period of gale southerlies affecting eastern regions of both islands and the capital. The polar air in behind the southerlies will bring a noticeable drop in temperature, plunging the country back into winter-like conditions after a fairly mild start to spring. Most of the South Island can expect single digit highs on Thursday.

The combination of strong, cold southerlies and frontal precipitation is a recipe for snow to low levels. Current forecasts are for snow to 300m around Southland, Otago, Canterbury and Marlborough, and 500m about parts of the North Island. “To top it all off,” said MetService meteorologist Angus Hines, “Significant and potentially damaging swells are going to charge up both sides of the country, starting Wednesday evening. This will be most noticeable along the east coast, where such swells are uncommon.”

Those waiting for more sunshine will need to wait until the end of the week; a ridge of high pressure extends over the country on Friday. However, due to the polar air which has been dragged over New Zealand earlier in the week, temperatures will remain cool. Overnight lows will be especially chilly, and frosts are likely to develop in sheltered areas across both islands.


Strong southerlies on Thursday morning, after the front. Courtesy of MetService Weatherscape.

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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