Climate Update 29 - November 2001

November

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder

Backgrounder
January to October total hydro lake inflow drought
National Climate Centre
Total New Zealand hydro lake inflows were lower than normal in October, adding another relatively dry month to a year so far of relatively low hydro lake recharge. Lakes right across the country have been affected, including the largest hydro lakes, Pukaki, Tekapo, and Taupo.

Checkpoint

Outlook and outcome – August to October 2001
Atmospheric pressure patterns were higher than normal to the east of the Chatham Islands, resulting in a tendency for a more northeasterly air flow than normal over New Zealand.
Rainfall was lower than expected over much of the North Island, near expected in much of Nelson and Marlborough, and lower than predicted over much of the rest of the South Island.
Air temperatures were generally higher than expected.
River flows for August to October were higher than expected in Northland, Auckland, Coromandel, and East Cape.

Climate

New Zealand Climate in October 2001
Timely rainfall in dry areas
Most of the North Island, Nelson, Marlborough, and east coast areas of the South Island from Kaikoura to Otago received average or above average rainfall, with double the normal rainfall in some places. In contrast the Southern Lakes area recorded half its normal rainfall. It was also drier than average in south Westland, Fiordland, and much of Southland.
Much of October's rainfall was from more frequent depressions than usual passing over the North Island. Pressures were above average to the south of the Chatham Islands.

November

Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows.
November 2001 – Number 29
October's climate: October rainfalls were high and well distributed – just what was needed in many of the drier parts of the country.
October's river flows: Flows improved in some areas.
Soil moisture levels: Soil moisture levels significantly improved.
Three month outlook: Rainfall and air temperatures are expected to be average to above average in most places, signalling a good start to summer for agriculture.
Checkpoint: How well are we doing wi

Three-month outlook

The outlook for November 2001 to January 2002
Ocean and atmospheric conditions in the Equatorial Pacific are near normal for this time of year, and sea surface temperatures are expected to remain near average through summer 2001–02. These features continue to indicate that a near-neutral state of the El Niño–Southern Oscillation will persist for the next few months.
Sea surface temperatures around New Zealand are likely to remain above average through the early summer, which will influence summer temperatures to some extent.

River flows

New Zealand River Flows in October 2001
Flows improved in some areas
Following a relatively dry September, above average rainfalls in October lifted river flows in the far north, East Cape, around Taranaki, and in Marlborough to above normal. Elsewhere flows were mostly below normal. A few catchments (darkest shade of pink in the map) had record low flows for the month.
Map of streamflow decile ranges in October
Streamflow decile ranges in October for rivers monitored in national and regional networks. The contributing catchment area above each monitoring location is shaded.

Soil moisture

Soil moisture on 31 October
Soil moisture levels significantly improved
The high October rainfalls have resulted in soils reaching field capacity in areas of the North Island, Nelson, Marlborough, and Kaikoura.