"Once these fronts pass through, calmer conditions are expected through into the weekend," she said.
"Today we are expecting showers across the region, some heavy with possible thunderstorms, mainly from afternoon.
"Tomorrow, rain develops with this second approaching front in the morning, heavy with possible thunderstorms, which ease in the evening as winds turn from the northwest to southwest.
"From Friday until the end of the weekend we are expecting areas of morning cloud, then mainly fine afternoons apart from isolated showers."
Parkes said the daily maximum temperatures for Rotorua and Tauranga were expected to be about average for this time of year.
"Tauranga ranges from about 23C through to 25C, whereas Rotorua is a tad cooler in the 19C to 22C range."
Heavy Rain Watch
Area:
Bay of Plenty east of Ōpōtiki and the ranges of Gisborne.
Valid:
12 hours from 10am to 10pm Thursday.
Forecast:
A period of heavy rain, with thunderstorms and localised
downpours possible. Rainfall amounts may approach warning criteria.