A thunderstorm watch is now in place for the Bay of Plenty.

The MetService is forecasting thunderstorms to develop around midday.

"Some of these may become severe from early afternoon until this evening, bringing localised downpours with intensities of 25 to 40 mm per hour," says a spokesperson for the weather organisation.

"There is also a low chance of a small tornado forming. The thunderstorms are expected to ease this evening.

"Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.

"Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain."

Area: Waikato, Waitomo, Taumarunui, Bay of Plenty, Rotorua, Taupo, Gisborne, Hawkes Bay, Taranaki, Taihape, Wanganui, Manawatu, Tararua, Kapiti-Horowhenua, Wairarapa
Valid: 7 hours from 2:00pm Thu 22 Dec to 9:00pm Thu 22 Dec