A northwesterly airflow strengthens over New Zealand today with a front sliding across the upper North Island during the day, weakening by evening. Another front (this time a cold change) moves onto the lower South Island around midday then slowly moves northwards. This front clears off to the northeast of the North Island early on Wednesday morning then expect a cold southwesterly airflow for the rest of the day.
Heavy rain and thunderstorms push northwards along the West Coast of the South Island today, reaching the lower / western North Island later in the evening. Showers about the upper North Island may be heavy with the chance of an isolated thunderstorm till evening then easing. The east coast of the North Island has a mainly dry day with northwesterlies strengthening at night. Dry for the east of the South Island although expect strong to gale northwesterly winds to develop for many especially inland, a cold west to southwest change pushes through Southland around midday then into Otago during the afternoon bringing some rain. This cold change reaches Canterbury in the evening.
Showers for the western North Island may be heavy with thunderstorms during Wednesday, easing in the evening. Snow lowers to 800m about the Central North Island. For the east coast expect some morning rain then the odd shower and sunny spells. Winds brisk from the southwest in the west, perhaps strong at times. For the South Island most rain / shower activity is about Southland although a few showers may affect other regions further north at times, some snow about Southland and Otago down to 400m, perhaps 300m at times.
By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz