Batten down the hatches New Zealand - a turbulent end to the week is on the cards.
Some areas may get over 100mm of rain, Weatherwatch says.
From today, a northerly wind is strengthening.
Afternoon thunderstorms are likely in inland regions in the southern part of the North Island today and tomorrow. They spread to the South Island tomorrow and Thursday as a low-level northerly wind strengthens.
Some storms may be severe, producing locally heavy rainfall exceeding 30mm in an hour - and 100mm over a few days - as well as gusty winds, and possibly hail, a Weatherwatch spokesman said.