Climate Update 43 - January 2003

January

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder

Backgrounder

Pacific ENSO signal
The orange-yellow shading along the Equator, stretching west from Ecuador, is a typical ‘footprint’ of the El Niño phase of the El Niño–Southern Oscillation.

Checkpoint

Outlook and outcome – October to December 2002
Rainfall was as predicted for the South Island, apart from Nelson-Marlborough which was drier than expected. Northland and Bay of Plenty were also drier than expected, and Hawke’s Bay and East Cape received more rain than predicted.
Air temperatures were generally lower than expected, apart from Marlborough where they were near average, and western South Island regions where below average temperatures were as predicted.
River flows were much as expected over most of the country.

January

Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows.
January 2003 – Number 43
December’s climate: Dry areas intensifying; near average temperatures for many places.
December’s river flows: December streamflows lower in North and East.
Soil moisture levels: Marlborough had temporary relief from early December rainfall.
Three month outlook: Drier than normal in the east; average conditions in most other places.
Checkpoint: How well are we doing with our predictions?
Backgrounder: New Zealand’s climate network.

This

Climate

New Zealand Climate
Temporary relief for Marlborough
Rain in early December meant rainfall was above average for the first time in six months in central Marlborough, but below average rainfall continued in eastern regions from Northland to Otago. In contrast it was cloudier and wetter than usual in some western districts.
Temperatures near average
Most regions had near average temperatures but it was warmer than normal in Hawke’s Bay and Wairarapa, and cooler than normal in Fiordland.

Three-month outlook

The outlook for January 2003 to March 2003
The enhanced cyclonic activity across southern New Zealand with episodes of stronger than normal westerly or southwesterly winds is expected to continue to influence late summer weather in New Zealand. The moderate El Niño event in the tropical Pacific is expected to last into autumn 2003, and should wane with conditions easing back to neutral by the end of autumn. It should remain weaker than the 1997–98 event.

River flows

New Zealand River Flows
December streamflows lower in north and east
December flows were low in the upper North Island, South Canterbury, and Central Otago. They were mostly normal or above normal elsewhere.

Soil moisture

Soil moisture
Marlborough had temporary relief from early December rainfall but significant soil moisture deficits were apparent there again from mid month, and similar dry conditions have spread throughout most of Otago and Canterbury.
Soil moisture was well below average for the time of year in eastern Northland, coastal Bay of Plenty, Gisborne, Hawke’s Bay, Manawatu, and parts of Wairarapa.

Soil moisture deficit in the pasture root zone at the end of December (right) compared with the deficit at the same time last year (centre) and the long term end of December average (left).