Taking it easterly this Spring

September 25, 2016

This week has seen a generally easterly flow across New Zealand, brought about by persistent high pressure to the southeast of the country, combined with low pressure systems sliding across the North Island. This has brought periods of rain or showers to many in the North Island, while people in the east of the South Island have had a dreary week, with cool temperatures, cloud and drizzle. On the other hand, Westland has had a mostly sunny week. Looking ahead, this weather pattern looks set to continue into the next week.

Due to this easterly flow, the wettest places over the past week have been the ranges of Coromandel Peninsula and the Kaimai Ranges, where over 200 mm of rainfall have been recorded at some stations between Monday and Saturday. In addition, a Severe Weather Watch is in force for these areas for further rainfall accumulations on Sunday. A Severe Weather Warning is in force for heavy rain for the Gisborne Region during Monday and early Tuesday.

Over on the South Island’s West Coast, it has been a different story. “On the usually wet and wild West Coast, Hokitika Airport has only recorded 0.4 mm of rainfall between Monday and Saturday, and many weather stations in Westland haven’t recorded any rainfall at all,” said MetService Meteorologist Claire Flynn. Hokitika had been seeing some rain today (Sunday), however.

The easterly wind flow is expected to continue throughout the next week as well, as the high pressure to the southeast of New Zealand refuses to budge. Low pressure systems coming from the Tasman Sea continue to trudge across the North Island as well. This means that the weather for the coming week will be similar to the week we have just experienced.

“When thinking of Spring weather, we usually think of westerly winds, and fronts coming from the south, so the last week and next week certainly aren’t your average Spring weather patterns,” Flynn said. “Though nor is it unheard of. The high pressure to the southeast of us has caused things to turn around for a while, but more typical Spring weather will make a return eventually.”

2016-09-25

Average surface pressure and winds, averaged over the next 10 days, based on ECMWF model data. This shows the high pressure system drawing an easterly flow over New Zealand. The broad trough to the north is the average of several troughs and lows moving over the upper North Island.

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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