SEASONAL CLIMATE OUTLOOK

What’s the Weather Doing Late in Summer?

Well – more of the same, actually

10th January 2010

Scientists at NIWA’s National Climate Centre say the current El Niño is well-established in the equatorial Pacific, and is likely to persist at moderate intensity through the rest of summer, before weakening during the autumn.

The scientists  say that spells more of the same for most of the country over the next three months:– similar conditions to those experienced in December.

According to the centre’s latest outlook, mean sea level pressures are likely to continue to be higher than normal to the north of the country and lower than normal to the south, resulting in stronger than normal westerlies over New Zealand.

Current dry soil conditions are likely to continue in the north and east of the North Island.

The same will apply in much of the eastern South Island, where below normal stream flows and soil moisture levels are likely through to March.

The centre says late Summer (January to March) rainfall totals are likely to be in the below normal range in the north and east of the North Island, normal or below normal in Nelson-Marlborough, and in the normal range in other regions.

Temperatures are likely to be average or below average in all regions, for the 3-month period (January, February and March) as a whole.

There will, of course, still be warm spells at times, especially in eastern regions in north-westerly wind conditions.

Rivers flows and soil moistures are likely to be below normal in the north and east of both Islands, but in the normal range in western regions.

Overall Picture

Temperature:

Air temperatures are likely to be average or below average in all regions. Sea surface temperatures are expected to be below average around and east of the South Island, but near normal to the north of New Zealand.

Rainfall, soil moisture, and stream flows:

Rainfall is likely to be below normal in the north and east of the North Island, normal or below normal in the northern South Island, and near normal elsewhere.

Below normal soil moistures and river flows are likely in the north and east of both Islands, with near-normal soil moistures and river flows likely in western regions.

The Regional predictions for the next three months:

Central North Island, Taranaki, Whanganui, Manawatu and the Wellington Region:

Seasonal temperatures are likely to be in the average or below average category.

lJanuary-March rainfall totals, stream flows and soil moisture levels are likely to be near normal.