An area of low pressure east of the South Island induces a cold south to southwest airflow to develop about the far south which then spreads northwards during the rest of today, westerlies for the North Island. This cold air spreads over the North Island on Wednesday.
Showery conditions for much of the western North Island today, easing by evening and long dry spells developing. Overnight showers pick up a bit about western coastal areas. The east coast of the North Island has a dry morning then spots of rain may spread from the west late afternoon / evening. Expect a period of early heavy rain for the West Coast of the South Island then easing, rain picks up again late afternoon / evening. Morning showers for Nelson / Marlborough then some sun breaks through. Canterbury is mainly dry with high cloud then showers move into South Canterbury in the evening, turning to rain and becoming heavy overnight, rain moves into North Canterbury overnight. Dry to start for the far south, showers move into Southland during the morning then Otago during the afternoon as southwesterlies freshen. Snow gradually lowers to 300m about the ranges.
Showers for the western North Island on Wednesday, becoming heavy in the afternoon with a risk of thunderstorms and hail then easing later on. Snow lowers to 500m about the Central Plateau. Rain or showers moves into Wairarapa in the morning then further north in the afternoon with a southwest change. Morning rain about the upper South Island may be heavy then easing to showers in the afternoon, becoming restricted to coastal areas in the evening, snow to 400m. The West Coast is mainly sunny, morning rain about North Westland clears. Showers about the far south for much of the day, snow flurries to 400 or possibly even 300m at times.
By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz