A thunderstorm watch is in place for the Bay of Plenty and Coromandel with the chance of some more heavy rain this morning.

According to tepukeweather.co.nz, 48.6mm of rain has fallen in the Bay of Plenty so far today.

A thunderstorm watch is in place for the region. Image: MetService.

The MetService is predicting more rain as a slow moving front lays over the northeast of the North Island.

"A front and band of heavy rain over the northeast of the North Island is forecast to move slowly eastwards onto eastern Bay of Plenty this morning and then away to the east this afternoon," says the weather organisation.

"The watch is for the possibility of localised downpours of 25 to 40mm/hr over Great Barrier Island, Coromandel Peninsula (mainly in the north) and Bay of Plenty east of Tauranga."

The risk of downpours eases from the west this morning and should clear eastern Bay of Plenty this afternoon.

Rainfall of this intensity can cause surface and/or flash flooding, slips and make driving hazardous.

Severe Thunderstorm Criteria

MetService uses the following criteria for severe thunderstorms in New Zealand:

Heavy rain (from thunderstorms):

Rainfall of 25 millimetres per hour, or more.

Large hail:

Hailstones 20 millimetres in diameter, or larger.

Strong wind gusts (from thunderstorms):

Gusts of 110 kilometres per hour (60 knots) or stronger.

Damaging tornadoes:

Fujita F1 (wind speeds greater than 116 kilometres per hour (63 knots)) or stronger.

Note: some tornadic systems such as funnel clouds, waterspouts and small land-based tornadoes are possible with thunderstorms that may not be classified as severe.