UPDATED 6:30pm, Friday

The latest from MetService on the thunderstorms moving in tonight and tomorrow.

A large low pressure area covers the Tasman Sea and New Zealand, and bands of showers are moving across the country. There is a high risk of thunderstorms developing in Northland late morning, then spreading this afternoon to Auckland,northern Coromandel Peninsula, Waikato, Waitomo and Taranaki. The thunderstorms are likely to be accompanied by localised brief heavy rain, winds gusts to 80km/hr, and possible small tornados. There is also a low risk of a damaging tornado.

Chart BELOW amended for introduction of risk of severe thunderstorms.

The next band of heavy showers and thunderstorms will move onto the west of the North Island this evening and cross the upper North Island overnight and Saturday morning.

There is a moderate risk of one or two thunderstorms becoming severe over northern Northland later this evening. These may produce brief heavy rain, hail of 10-15mm possible damaging wind gusts of 110+km/hr and a possible small tornado about the northeast coast. Then over the rest of Northland and northern Auckland and extending down into north Taranaki, there is a moderate risk of thunderstorms developing by the end of the period giving localised brief heavy rain, small hail, wind gusts to 90km/hr, and possible small tornados.

There is now a moderate risk of thunderstorms in northwest Marlborough for a few more hours this evening.

A low risk of thunderstorms extends across into Bay of Plenty and Taupo, and down into north Westland, as indicated on the chart.

No thunderstorms or significant convection expected elsewhere.

The low starts to move southeastwards towards central New Zealand from Saturday afternoon. Further bands of showers and rain are expected to spread across northern and central New Zealand. The high risk of thunderstorms persists in the northwest of the North Island as before, with still a low risk of damaging tornados. There are likely to be further heavy thundery falls in the Bay of Plenty. In Nelson and northern Marlborough, the high risk of thunderstorms continues.The likelihood of heavy rain increases in this area, while the risk of hail and small tornados diminishes.

– MetService/NZ Govt