This Saturday a large and deep low will move towards the South Island. There is likely to be some wild weather in many places with heavy rain on the West Coast of the South Island, gales being a main feature for the North Island and parts of the South Island. Snow will also feature high on the list for inland parts of the South Island above 400 meters.
The reason for the heavy snow potential given by WeatherWatch.co.nz forecasters is we’ll have a northerly airflow coming in from the northern side of the low bringing in lots of moisture then on the southern side of the low a cold southeasterly airflow undercuts the northerly airflow riding above. This type of snowfall is called warm advective snowfall and can lead to large amounts of snow falling.
A similar situation happened on the 6th June 2012 earlier this year however the air at the surface was much colder then hence snow fell to sea level. This system about to bear down on us will be quicker moving but fairly intense as it moves through.
For Saturday, heavy snow at this stage is likely to fall to 400m from Inland Otago up into South and Mid Canterbury, 500m and above for North Canterbury then down to 600m in Marlborough. Conditions are forecast to ease in all areas later at night.
Farmers and people travelling in the high country of the South Island this weekend are advised to take note and keep up to date with how this system will develop.