Tropical moisture drenching New Zealand
A trough is dragging very humid, tropical air from much lower latitudes over New Zealand, resulting in widespread heavy rain.
New Zealand's North Island and upper South Island are receiving a drenching at the moment, with rainfall amounts of 50-100mm in some areas such as Northland and Nelson. The rain is coming from the north, dragged south by a trough firmly positioned over the country. The heavy rain is expected to continue well into Monday, with some places likely to receive a further 100-200mm, at times falling as much as 20-30mm per hour. Alongside delivering heavy rain, the synoptic conditions are conducive to thunderstorm formation, and a Severe Thunderstorm Watch is current for much of the western side of the North Island and the northwestern area of the South Island.
A cold front that recently crossed Tasmania and southern Victoria is on its way to New Zealand, and will push the trough away from the South Island, however it looks as though the trough will be anchored over the North Island for a while yet. The cold front will also bring some more rain to the South Island, albeit not as much as the trough has produced, though good for lower parts that are currently very dry and missed most of the rain that fell to the north.
Looking ahead, forecast models have Tropical Cyclone Gita, currently east of Tonga and moving westward, making a very large but slow u-turn over the South Pacific, and could impact parts of New Zealand in around a week or so.
© Weatherzone 2018