Updated 8:49pm: A tropical cyclone has formed near Vanuatu and while short lived (likely only a day or two, as it’s tracking south out of the tropics) it will soon morph into a new storm system in the NZ area. This is what tropical cyclones do when they move southwards and leave the “tropical” part that creates them. As they change into this new, colder air, fuelled storm/low near our country the severe weather moves out from the centre and becomes scattered further afield – this process will create areas of severe weather for parts of NZ in the coming days.

At the time of recording this video the cyclone was not officially named by the Fiji Met Service – but tonight the Fiji Met Service named the Tropical Cyclone “Tam”.

Cyclone Tam is now a Category 1 storm with gale force winds around the centre. Category 1 is damaging, but it is also the lowest on the tropical cyclone scale (which goes up to five). In comparison, Cyclone Gabrielle had Category 3 strength when it reached New Zealand just over two years ago.

Ex-cyclones, even once winds have eased, can bring flooding if high pressure near New Zealand slows it down – or stalls the rain in one area for days. High pressure is likely to be in that position in the days ahead, which is why forecasters are tracking this low so closely.

#Developing: Tropical #CycloneTam has formed near Vanuatu. It's likely to be a fairly short lived Cat1️⃣ cyclone as it tracks southwards away from land. As it moves towards #NZ it will transition to extra-tropical. This changes the structure, but brings severe weather risks here. pic.twitter.com/cmlBrOzBi9

— WeatherWatch.co.nz (@WeatherWatchNZ) April 15, 2025

Powerful high pressure to the east of NZ will create a “squash zone” (a line of windy nor’east weather) as the storm approaches NZ in the next two days.

Heavy rain will also slide southwards with heaviest falls in the north of both main islands. High pressure may well stall the rain in some nothern regions which means forecasts may change, especially due to our mountains and ranges breaking up some of the flow of rain and wind as this all moves through.  Also the low will be changing shape in the days ahead – that also alters where the bulk of the severe weather goes.

Slips, flooding, large waves and travel problems are all possible over the next few days in certain regions.

There will also be dry and calm areas across some areas with below normal rainfall for this time of year (mostly southern parts of both main islands – but see the video for more).

We give you the next full forecast for this week and the long Easter Weekend on Wednesday.

• WeatherWatch.co.nz