Week Ahead: High Country Snow and Coastal Otago Heavy Rain
After much anticipated waiting and numerous drastic swings in model data, the moment is finally approaching. Commencing today, precipitation will start to develop on the West Coast as the expansive low gradually moves nearer to New Zealand. Strong winds and heavy rainfall are poised to dominate both islands, with the North Island projected to experience minimal cumulative effects, aside from the East Coast on Thursday (refer to our significant weather outlook). There are numerous substantial weather hazards at play, and we strongly recommend staying informed by regularly visiting our in-depth analysis section, updated in the evening for the upcoming day.
It is important to note that the forecast is currently indicating heavy rainfall for both the east and west coasts of the South Island. Coastal Otago stands out as the main area of concern, with the possibility of over 100mm of rain accumulating over the next three days. The East Coast of the North Island, although experiencing a dry year so far, is also at risk of heavy rain later in the week, and depending on where the heaviest rain sets up; surface flooding, rapid stream and river rises are possible. While Canterbury poses a slight risk due to previous model data suggesting significant rainfall, it is projected that no more than 50mm will fall at this stage.
We have a series of maps showcasing the extensive size of this low-pressure system and the significant amount of precipitation it is carrying.
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Tuesday
Wednesday
The likelihood of snowfall has shown steady consistency in recent days. Late on Monday night, a surge of cold air is forecasted to advance up the lower South Island towards South Canterbury by early Tuesday morning , extending to North Canterbury by Wednesday. Snow is anticipated to fall between 400-500 meters above sea level for Southland, Otago and South Canterbury, and above about 600-700 metres for North Canterbury. At present, total snow accumulation ranges from 20-50cm (higher amounts at those higher levels) throughout the week and have resulted in ENHANCED and HIGH risks as indicated in our In-depth analysis and Significant weather Outlook . It is unlikely we will see snow below 900 metres on the North Island.
Roads at elevated areas including alpine passes maybe affected and could lead to closures by the NZTA, and heavy snowfall and associated wind chill could pose risks to livestock. It is considered unlikely that snow levels will not lower below the mentioned altitudes (+-100m). Nevertheless, as conditions are highly changeable, all precautions should be taken into account.
The snow maps presented below are generated by one of our weather models, illustrating the projected amount of snowfall for each day. It is crucial to note that these maps serve solely as an indication and should be utilized with caution - remember to always follow our forecaster produced forecasts rather than raw model data.
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Tuesday
Wednesday
PLEASE ensure you keep up to date with or In-Depth Analysis and our Significant Weather Outlook for up to date information.
In-depth Analysis: https://www.severeweather.co.nz/in-depth-analysis (Typically issued by 8pm each evening)
Significant Weather Outlook: https://www.severeweather.co.nz/ (Typically issued by 9pm each evening)
