Very cold cold air with snow making potential is due to hit Southland later this evening. The snow risk mainly lies in Southland, coastal Otago and North Canterbury. Parts of Central Otago and South Canterbury will also get a few flurries but due to the southwesterly airflow it will be a little more sheltered there then coastal areas in terms of receiving snowy weather. The ranges in Fiordland and through to South and parts of North Westland also carry a risk.

Snow will develop to 500m this evening in Southland then lowering to sea level by late Tuesday morning, snow showers will then clear at night. Accumulation of 5 to 10cm to 500m and 3 to 5cm to sea level is possible. Temperatures are not likely to get above 6 degrees in Southland on Tuesday so it will be a very cold day.

Some snow will fall in Central Otago today to 700m spreading from the west, expect 3 to 5cm. Early tomorrow morning the flow changes more southwesterly, a maximum of a further 3 to 5cm of snow to low levels is possible during the day clearing in the evening however the result may only be a centimetre or two on Tuesday. It will likely be very cold on Tuesday not getting above 4 degrees, severe frosts can be expected on Tuesday night so black ice will be a concern for Wednesday morning.

About coastal Otago, bitterly cold strong to gale force southwesterly winds develop tomorrow morning bringing snow flurries to sea level which clear on Wednesday morning. All up 5 to 10cm could accumulate to sea level during this event however due to snow melt at times final amounts could be in the range of 3 to 5cm. Tuesday will be very cold with temperatures not getting above 6 degrees however no frosts at night as southwesterly winds will keep temperatures just above 0 degrees.

For the likes of coastal Canterbury mainly about Banks Peninsula and Christchurch expect strong cold southwesterlies to develop by midday tomorrow, sleety showers develop in the afternoon and there is even the chance of a few sea level snow flurries later in the evening. Accumulations will likely be 5 to 10cm on Banks Peninsula to 300m, 3 to 5cm down to 200 maybe even 100m. A slim chance of a centimetre or two accumulating to sea level. South Canterbury can be quite sheltered from these southwesterly airflows so while it will be cold the snow risk is low, perhaps 1 or 2 centimetres to low levels in the afternoon and evening then clearing at night. For inland North Canterbury 3 to 5cm to low levels is possible in the afternoon and evening then clearing at night.

Low level snow flurries will also develop about the Kaikoura coast late afternoon on Tuesday clearing overnight with the potential for 3 to 5cm. And in Wellington showery conditions develop late afternoon or evening tomorrow, snow in the ranges to 600m lowering to 200m overnight. 5 to 10cm possible to 600m and 3 to 5cm possible to 200m. A few sleety showers may even make it into the capital early on Wednesday morning for a time.

Homepage image / Andrew Dallow

By weather analyst Aaron Wilkinson, WeatherWatch.co.nz