Heavy showers similar to those accompanying last night's thunderstorms are forecast for Tauranga later today, making St Patrick's Day a damp one this year.

The slow moving front bringing the rain is moving down from the Coromandel peninsula where heavy rain overnight isolated the town of Whitianga this morning.

The MetService expects heavy rains to hit the Western Bay of Plenty tonight. Photo: File

Metservice communications meteorologist Lisa Murray rain is expected to begin falling heavily in the Western Bay of Plenty tonight at about 9pm.

'The taxis will probably do quite well out of it,” says the former Dubliner.

'There will be periods of heavy rain mainly tonight and Friday morning. Localised downpours are possible. You could get even more than 30mm in an hour.

'There is potential for localised flooding, surface flooding on roads, slips also driving conditions visibility can be compromised.”

Last night's thunderstorm over Tauranga saw about 100 lightning strikes in the Western Bay as the front moved through, with about 10mm of rainfall recorded between 9pm and 10pm. Tauranga airport recorded 15mm of rainfall.

The majority of it was in the big burst between 9pm and 10pm.There was another downpour at about 2am.

Today's weather watch advises of periods of heavy In the 24 hours between 10am Thursday and 10am Friday, when a further 80 to 120mm is possible, especially in the north.

Localised peak intensities in excess of 30mm per hour are likely, especially this morning and again tonight. The cause is a slow-moving trough currently over the Coromandel Peninsula.

This trough is expected to bring further bursts of heavy rain the region today and then should move southwards by tonight and Friday morning, with heavy rain possible in Western Bay of Plenty and Eastern Waikato.

While a heavy rain weather watch for the Coromandel Peninsula has now been upgraded to a full warning.