Heavy snow, rain and bitterly cold southwest gales
MetService News Release
Monday 24 September 2018
Snow has fallen to 300 metres over parts of southern New Zealand this morning, and there’s more snow to come through to the middle of this week.
A Severe Weather Watch for heavy snow remains in force for eastern parts of the South Island. Snow is also expected to affect most of the South Island highway passes, with Road Snowfall Warnings reissued this morning.
“The heaviest snow is expected in Otago this afternoon and evening, then Canterbury this evening and Tuesday morning,” MetService Meteorologist Peter Little said. “Snow is expected to fall down to around 300 metres in parts of southern New Zealand today and Tuesday, with significant accumulations possible above 400 metres. Rain is likely at lower elevations, which could approach warning amounts in eastern Otago and South Canterbury.”
“A slow-moving low-pressure system east of the South Island is forecast to deepen today, directing a cold and moist southeast flow over the South Island. The low moves away to the east on Tuesday, with the cold air spreading over the North Island. Snow will start to fall about higher parts of the North Island, and the Desert Road will likely be affected. Snow is also expected to lower to near sea-level over southern New Zealand Tuesday evening.”
“Cold temperatures are expected across the entire country on Tuesday, with a maximum of just 10°C forecast for Wellington and low teens for much of the remainder of the North Island. Strong to gale force southwest winds will add significant wind-chill too, making it feel much colder. A Watch for severe southwest gales has been issued for southern parts of New Zealand.”
Graphic showing strong to gale force southwesterlies in many places Tuesday afternoon
“On Wednesday, wintry showers and gale force southwesterlies continue in the far south, but showers and winds begin to ease across the remainder of the country.”
“A ridge of high pressure moves onto the country from the Tasman Sea on Thursday, providing a more settled end to the week’s weather. Although daytime temperatures begin to recover, horticulturalists and gardeners should be aware there’s a risk of overnight frosts in some areas.”
MetService issues Warnings, Watches and Outlooks for severe weather over New Zealand.
Warnings are about
* When severe weather is imminent or is occurring
* Issued only when required
* Recommendation: ACT
Watches are about
* When severe weather is possible, but not sufficiently imminent or certain for a Warning to be issued
* Issued only when required
* Recommendation: BE READY
Outlooks are about looking
* To provide advance information on possible future Watches and/or Warnings
* Issued routinely once or twice a day
* Recommendation: PLAN