Weather: Thunderstorm, lightning risk across New Zealand

New Zealand is at risk of thunderstorms on Wednesday afternoon as southeast winds meet southwest winds over the country.

"The warmer airmass still over the upper North Island (along with cold temperatures further up in the troposphere) means the 'fuel' for thunderstorms formation is there," MetService says.

"We have a moderate risk for these thunderstorms to form over parts of the Bay of Plenty, Taupo, inland Waitomo and Taumaranui this afternoon where southwesterlies in the north are expected to converge with southwesterlies further south which will act as the 'trigger' for thunderstorms.

"Thunderstorms are also possible over the Tasman ranges today but remember, thunderstorms are very localised in nature so everyone in a moderate risk will not get caught one!"

NIWA has issued a map showing the risk across New Zealand for lightning strikes on Wednesday.

There's a large patch forecast for the central North Island, as well as a cluster around Nelson and a line running up the West Coast.