Climate Update 45 - March 2003

March

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder

Backgrounder

ENSO signal approaching neutral
The current El Niño phase of the El Niño-Southern Oscillation is nearing its end. Sea surface temperatures in the equatorial region of the eastern Pacific have fallen, and subsurface temperatures are now close to zero.
Most forecast models of the development of the El Niño-Southern Oscillation are predicting neutral conditions through autumn and winter.

Mean sea surface temperature departures from normal.
Update on the SOI
The mean Southern Oscillation Index (SOI) for February was -0.9, with the three month average now at -0.8.

Checkpoint

Outlook and outcome – December 2002 to February 2003
Rainfall was near or below average as predicted in most regions, but above average in a few areas of the northern North Island. It was drier than expected in the southwest North Island.
Air temperatures were near or below average in most regions as expected.
River flows were variable. Above normal flows occurred in parts of Northland, Waikato, and East Cape.

March

Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows.
March 2003 – Number 45
February’s climate: February was cooler than normal in many places, with some unseasonal frosts.

Climate

New Zealand Climate
Low rainfall in central regions of New Zealand
Waikato, Taranaki, and Nelson all received less than a quarter of their normal February rainfall, while less than half of the average fell in the far north of Northland, and in most central and southwestern areas of the North Island. Totals were less than 75% normal in southern Wairararapa, north Canterbury, and west Otago.

River flows

New Zealand River Flows
February flows low over much of New Zealand
Apart from high streamflows in parts of Northland, Coromandel, and East Cape, and normal flows for the South Island west coast, most rivers and streams were running lower than normal over the country.

Soil moisture

Soil moisture
Severe soil moisture deficits along the east coast of the South Island, and in Nelson and parts of Otago, remained through much of February. North Island soils were dry for much of the month.