Climate Update 72 - June 2005

June

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder

Backgrounder
Special purpose climate stations - complementing the national climate network.
Besides maintaining a national climate reference network and data archive, NIWA frequently deploys special purpose climate stations to collect vital data for projects or to ‘fill in’ knowledge of the climate in data-sparse areas.
The additional weather stations can support climate sensitive industries such as agriculture and horticulture.

Checkpoint

Outlook and outcome – March 2005 to May 2005
Rainfall was below normal as predicted in the north of the North Island, but wetter than expected in Bay of Plenty, eastern North Island, and in Marlborough.

June

Climate Update is a summary each month of New Zealand’s climate, including soil moisture and river flows.
June 2005 – Number 72
May’s climate: Record high rainfall in Bay of Plenty. Well above average temperatures in the North Island.
May’s river flows: Some very high river and stream flows, and contrasting low flows in the north of both islands.
Soil moisture levels: Soil moisture recovery in northland.
Three-month outlook: In spite of the usual cold snaps, air temperatures are likely to remain above average in the North Island and north of the South Island.

Climate

New Zealand climate in May 2005
Record rains lashed Bay of Plenty, with severe flooding. Tauranga recorded 634 mm (695 percent of normal), its wettest calendar month for any time of the year in more than a century, including its heaviest 1-day rainfall on record (347 mm on 18 May).
May was very much warmer than usual in the North Island, but temperatures were below average along the South Canterbury and Otago coasts.

Three-month outlook

The outlook for June 2005 to August 2005
While northeasterly wind flows were predominant over northern New Zealand in May, the coming three months are likely to feature enhanced westerly wind flows over the country, the result of expected below average sea-level pressures well to the south.
The maps below show the expected conditions. Air temperatures are likely to be above average in the North Island and northern South Island, and average or above average elsewhere.

River flows

River flows
Contrasting high and low river and stream flows
High streamflows in Bay of Plenty, the east coast of the North Island, Taranaki, and coastal regions of Marlborough, North Canterbury, and Southland contrasted with low flows in Northland and much of the northern half of the South Island. Near normal flows occurred in the central North Island and much of the southern half of the South Island.

Percentage of average May streamflows for rivers monitored in national and regional networks. The contributing catchment area above each monitoring location is shaded.

Soil moisture

Soil moisture recovery in northland
Northern soil moisture levels rose following high rainfalls particularly in Northland and Waikato, but also in Manawatu and Horowhenua. At the end of May, soils were unusually wet from Bay of Plenty down the east coast to Kaikoura. Otago soils remained a little drier than average in some places.
 
Soil moisture deficit in the pasture root zone at the end of May (right) compared with the deficit at the same time last year (centre) and the long-term end of May average (left).