Climate Update 75 - September 2005

September

New Zealand Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder

Backgrounder
Climate science meets virtual reality

Virtual climate station network (red dots) in the southern North Island. Estimates of daily rainfall, air temperature, evapotranspiration, soil temperature, and wind speed have been made at each site, and can be interpolated between sites.

Farmer community group meeting in west Otago discusses pasture management during an unusually warm winter.

Checkpoint

Outlook and outcome – June 2005 to August 2005
Rainfall was near normal, as predicted, in parts of Northland, Waikato, and the east of the North Island, but below normal over much of the rest of the country.
Air temperatures were above average in many places as was predicted, but lower than expected in parts of the east and north of the North Island.
Streamflows were near normal, as was predicted, in the south and southwest of the South Island, and below normal elsewhere.

 

The outcome maps shown here give the tercile rankings of the rainfall totals and mean temperatures that ev

New Zealand Climate

New Zealand climate in August 2005
August was much drier, warmer, and sunnier than normal over most of New Zealand. Many northern and eastern regions of the country recorded less than 50 percent of normal rainfall.
Air temperatures were higher than usual, with the national average temperature of 9.8 °C being 1.1 °C above normal.

Three-month outlook

The outlook for September 2005 to November 2005
Local atmospheric circulation patterns are expected to result in more anticyclonic conditions than usual to the east of the South Island, and weaker westerly wind flows, over New Zealand.
Sea surface temperatures around New Zealand are likely to be near or above average until November 2005.
Air temperatures (see maps below) are expected to be above average in the North Island, and average or above average in the South Island.
Rainfalls are likely to be normal or above normal in the east of the North Island and north of the South Island, and near

River flows

River flows
Mostly low river and stream flows
River flows were below normal nearly everywhere, apart from the Buller and Fiordland regions, where they were near normal.

Average August river and stream flows(%) at monitored catchments. NIWA field teams, regional and district councils, and hydro-power companies are thanked for providing data.

September

Climate Update is a summary each month of New Zealand’s climate, including soil moisture and river flows.
September 2005 – Number 75
August’s climate: Drier, warmer, and sunnier than usual for most of the country.
August’s river flows: Mostly low river and stream flows.
Soil moisture levels: Continuing low soil moisture.
Three-month outlook: Above average temperatures in the North Island, average or above in the South Island. Mostly near normal rain.

Soil moisture

Continuing low soil moisture
Soils in much of Otago and parts of coastal Canterbury continued to be drier than normal in August. In some areas, soil moisture deficits developed that were 50–60 mm below the average for the end of August.
 
Water balance in the pasture root zone for an average soil type where the available water capacity is taken to be 150 mm.