A shot of cold air is expect to spread across the South Island today and tonight.

As we mentioned earlier, this could be the spark that sets off a few thunderstorms this afternoon and this evening about eastern Canterbury and eastern Otago.

This new air mass is cold enough that some of the precipitation may come down in the form of flakes rather than liquid.  Current indications lead WeatherWatch.co.nz forecasters and MetService forecasters to believe brief period of snow is possible for the Canterbury High Country during the overnight hours.  Accumulations of 4 to 6 cm are possible above 900m with lesser amounts down to 600m.  No snow is expected below 600m.

As a result, government forecaster MetService has issued the following Road Snow Warnings:

• Lewis Pass- A period of rain is expected Monday morning with accumulations of 1cm of snow possible near the summit

• Porters Pass- Rain is expected to develop this evening and turn to snow for a time Monday morning.  4 to 6cm of snow is expected to accumulate near the summit during Monday morning with lesser amounts further down.

• Lindis Pass- Patchy rain is expected this evening with 1cm of snow possibly accumulating near the summit.

Farmers should be aware that cold, snow and breezy conditions may also put stress on livestock.

Homepage image/ Jude Wightman

WeatherWatch.co.nz