Retrospective: November-January 2019 Outlook

The November 2018 – January 2019 atmospheric circulation around New Zealand was forecast to be characterised by higher pressure than normal around the country and lower pressure than normal to the southwest. During the three-month period westerly quarter air flow anomalies were expected, with periods of easterly quarter air flows. 

Actual pressures were slightly below normal across New Zealand, with higher than average pressure to the southeast and average pressure to the northwest. This gave a mixed flow pattern with a favoured easterly flow.  

Predicted air temperature: November 2018-January 2019 temperatures were forecast to be average or above average for all regions of New Zealand.  

Outcome: Actual temperatures were above average across most of the North Island, with only a few areas recording near average temperatures (western and far northern Northland, parts of Auckland, western Waikato, eastern Gisborne and coastal Manawatu-Wanganui). For the South Island, near average temperatures were observed in parts of Canterbury and Otago, while above average temperatures were observed elsewhere.

Predicted rainfall: November 2018-January 2019 rainfall totals were forecast to be near normal or below normal for most of regions of New Zealand except the west of the South Island where above normal rainfall was most likely.

Outcome: For the North Island, actual rainfall was near normal in the west, and above in the east and north. For the South Island, near normal rainfall was observed in the west, below in the north, and above in the east.