A low sat in the western wings this week sending periods of rain to the South Island’s west coast throughout the week.
However, it wasn’t until Thursday that the system sent its final performer over the entire New Zealand ‘stage’ in the
form of a trough which eventually merged with the former Tropical Cyclone (TC) Donna. This duet between the trough and
remnants of TC Donna meant large rainfall accumulations and gale force gusts over parts of the North Island.
Much of the North Island and northwest corner of the South Island were put under severe rainfall watch or warning from
Thursday through to Friday as the trough, fuelled with moist air from the remnants of Donna, made conditions ripe for
persistent rain and brief downpours. “Nelson was soaked early Thursday, with a torrential downpour of 49mm in one hour
recorded in Collingwood” reported April Clark, meteorologist at MetService.
“Prolonged rain affected the North Island later Thursday and into Friday, with the heaviest falls observed about the
higher ground north of the central plateau. A rain accumulation of 269mm was recorded over a 36 hour period from
Thursday midday in the Gisborne ranges” she continued. As the remnant low of Donna passed to the east of the North
Island on Friday winds turned strong southerly with severe gale gusts recorded in exposed places on the eastern coasts
of the North Island.
Though it wasn’t a dry end to the working week, the South Island generally fared better during the performance of the
trough and Donna, though southerly winds and clear skies meant frosty temperatures for those east of the Alps this
Mother’s Day morning.
Looking ahead, another low is expected to move eastwards over the country on Thursday bringing periods of rain ahead of
it, and cold showery southerlies behind. The southerlies bring the potential of snow falling to the lowest level since
last season.