Whanganui’s summer season may start off with heavy rain, according to Niwa’s seasonal climate outlook.
Heavy rain is possible for early December, with stronger winds than normal and warm, humid conditions anticipated for the summer months ahead in the river city.
The National Institute of Water and Atmospheric Research (Niwa) has released its seasonal climate outlook for December to February and for the Central North Island region.
After the rainy start, drier-than-normal conditions are expected to follow.
Temperatures are equally likely to be near average or above average and spells of warm, humid conditions are likely during December.
Across the whole country, there are similar spells of hot, humid conditions that look likely, and localised marine heatwaves may form in the months ahead affecting sea temperatures.
But people should also be prepared for the wind to pick up, as wind speeds are expected to be stronger than normal.
Soil moisture levels and river flows are about equally likely to be below normal or near normal.
El Nino’s ongoing impact through summer
El Nino’s continuing presence was felt during November, and there’s a 100 per cent chance of that persisting through summer.
The combination of an atypical El Nino alongside other active weather systems brings an increased chance of a more variable-than-normal start to the summer season.
Despite the non-traditional El Nino impacts, an increased awareness around the risk for dry spells is recommended across several regions which may contribute to water restrictions, particularly in areas that may not have had them in recent years.
As of late November, fire danger was low across the country, but variable fire danger conditions are expected in December.
Property owners are encouraged to keep on top of grass growth, as grass may dry out and become a wild fire fuel source.
As the summer season progresses, the eastward propagation of the warmest water in the tropical Pacific may see circulation patterns become more El Nino-like.
More frequent high pressure to the north of the country will also reduce, but not eliminate, the chance for ex-tropical cyclones.