Retrospective – January to March 2015 Outlook

During January – March 2015, lower pressures than normal were forecast in the western Tasman Sea. Pressures were also expected to be lower than normal to the northeast of the North Island, and higher than normal to the southeast of the South Island. This pressure pattern was expected to be associated with a disturbed westerly flow in the Tasman, and northeasterly flow onto the North Island from time to time.

Actual mean sea level pressures for the forecast period were higher than normal to the southeast of New Zealand and near normal over the country as a whole. This brought about a weak south-westerly flow anomaly across the country

Predicted rainfall: January – March 2015 rainfall is likely to be in the near-normal or above normal range in North Island regions, most likely near-normal in the north of the South Island, and likely near-normal or below normal in all other regions of the South Island.

Outcome: Actual rainfall was below (50-79%) to well below (<50%) normal for the entire North Island as well as the north and east of the South Island. Rainfall for the west of the South Island was largely in the near normal range with the exception of inland areas where rainfall was slightly below normal.

Predicted air temperature: January – March 2015 temperatures are most likely to be in the above normal range in the west of the South Island, and likely to be near-normal or above normal in all other regions.

Outcome: Actual temperatures were above average for most parts of the country with the exception of Waitomo, Gisborne, Hastings, Central Hawke’s Bay, Ashburton, Timaru, Clutha and parts of Southland where near average temperatures were observed.