Dr Kathleen Kozyniak
Principal Scientist Air
Hawke’s Bay Regional Council
September’s rain was a big relief. The region received above average rainfall and in some areas, well above average. That included the Ruataniwha Plains, the south coast and northern Hawke’s Bay. Soil moisture levels are either near or above median levels for the time of year, which is encouraging for the start of spring. I understand that some people are still finding it quite dry at depth though.
River flows could do with more rain and remain below seasonal averages in places such as the Ngaruroro Catchment. Groundwater levels continue to be stubbornly below normal for the time of year. Air temperatures were average for September and soil temperatures ended September on about 12°C on the Plains and 9°C on higher ground.
I mentioned last time that a tussle was happening between different climate influences and thankfully during September those favouring wet weather appeared to win. They include a waning Indian Ocean Dipole, warm seas around us, and a La Niña event that looks increasingly on the cards. On the other hand, sea level pressures are forecast to be higher than normal over eastern and southern New Zealand in the next three months, potentially bringing drier skies.
Falling out of that mix is a forecast for near or below normal rainfall and warmer than usual temperatures for the few months ahead. The start of the tropical cyclone season is almost upon us and the latest forecast is for an increased chance of one or more ex-tropical cyclones bearing down on northern New Zealand during the season. Hopefully we don’t end up with a dreaded mix of drought conditions and one torrential storm!
Percentage of Normal Rainfall