Clark said temperatures would remain similar to what they have been, average during the day and a little bit warmer than average overnight.
Wednesday should clear up with westerlies coming in, although there may still be some showers around the eastern ranges. Westerlies would likely get gusty around Tauranga.
Another front approaches on Thursday and the Bay of Plenty could expect more cloud while on Friday the front "cruises" over the region with rain developing into heavy falls around the eastern ranges.
Clark said as usual for autumn, the weather this week was changeable - the calm and steady weather the region had been expecting was not typical for the season.
"It will be a bit of a shock to the system."
Parts of the Bay of Plenty have seen above-average temperatures and dryness during autumn - with some locations approaching records.
Niwa forecasting principal scientist Chris Brandolino said Tauranga, Whakatāne and Te Puke temperatures for the autumn season so far were about 1C above average.
When temperatures reach more than 1.2C above normal, that is considered well above average.
Brandolino said this meant autumn in these centres was warm but not quite record-breaking.
Rotorua's temperatures were currently sitting at 0.9C above average.
The city was on track for its second-driest autumn on record - but Brandolino said this may yet change, particularly as rain was forecast in coming days.
Te Puke was on track for its driest autumn on record up to 1973, and Taupō was heading towards its second-driest on record.