By Rebekah LaBar, MetService Meteorologist Satellites are one of a meteorologist’s best tools. Satellite images can tell us where weather systems are and how fast they are moving. They can also often help us distinguish between many things such as thick and thin clouds and high and low clouds, as well as detecting snow, fog, volcanic ash, smoke, thunderstorms, and much more.
By Rebekah LaBar, MetService Meteorologist
The low-pressure system that brought cold weather, snow, and thunderstorms to New Zealand is pulling off to the east today. An unsettled southwest flow will continue to dominate the weather this week, although temperatures will gradually rise as we head towards the weekend and the recent snowfalls will start to melt.
A deep upper-level trough of low pressure is moving over the South Island of New Zealand today, while an associated surface low lies to the southeast. The trough is dragging up cold air all the way from Antarctica in our first significant cold outbreak of the year that will continue to bring snow to parts of the South Island and high elevations of the North Island today and tomorrow. Thunderstorms with small hail are also possible. As the low-pressure system strengthens, it will also bring strong winds and high swells to coastal areas of especially the South Island.
A burst of cold air originating from the Antarctic ice sheet is expected to affect New Zealand on Monday and Tuesday. Unseasonably cold temperatures, strong winds and snow to low levels are expected over the South Island where this event is likely to have a high impact. Snow is forecast down to around 200 to 300 metres in Fiordland, Southland and Otago but 400 to 500 metres in Canterbury. Hail and snow flurries could penetrate even lower. People in places such as Invercargill and Dunedin may see some snowflakes that melt as they hit the ground.
A burst of cold air originating from the Antarctic ice sheet is expected to affect New Zealand on Monday and Tuesday. Unseasonably cold temperatures, strong winds and snow to low levels are expected over the South Island where this event is likely to have a high impact. Livestock could be affected and it will probably have an effect on higher roads where significant snow accumulations may make driving conditions difficult and could lead to some road closures.
Update by Peter Little, MetService Meteorologist, at 4.30pm
A polar blast due early next week will see temperatures plummet in many places, with snow expected to unseasonably low levels over the South Island and lower North Island. On Monday, MetService is expecting snow to fall to 400 metres in the far south of the South Island and to 600 metres on Banks Peninsula. Early Tuesday, snow is expected to lower to 900 metres for a time on the Tararua Range.
For much of New Zealand it was a warm Easter break with many places recording temperatures well into the twenties. On Easter Sunday, 5th April 2015, the warmest spot in the country was Kawerau in the Bay of Plenty when the thermometer reached 25.7°C. However, as we look ahead to this weekend the forecast looks very different, with cold air spreading across New Zealand from Sunday.
What’s the forecast?
Each year on 23rd March, National Weather Services around the globe celebrate World Meteorological Day. This marks the establishment of the World Meteorological Organization (WMO) on this day in 1950. WMO is the global co-ordinating agency for meteorological and hydrological activities, formed because weather simply doesn’t limit itself to national boundaries.
Cyclone Reuben crossed latitude 25 South overnight last night, with the Wellington Tropical Cyclone Warning Centre assuming high seas warning responsibility for the system this morning. As Reuben continued to move southwards it weakened, and at midday today (NZDT) was re-classified as an extra-tropical low.
CHRIS NOBLE, MANAGER PUBLIC WEATHER SERVICES
18 March 2015
Now that Cyclone Pam has passed the Chatham Islands, here's a look back at events of the last couple of weeks...