Rural Monthly Outlook:

Some relief in sight for farmers in February


1 February 2019

January 2019 - High pressure, high temperatures, low rainfall

January was characterised by frequent high pressure centred over the Tasman Sea and extending onto the North Island. Prevailing southwesterly winds affected the country. The combination of Highs and relatively dry southwesterlies produced a very dry month for areas north of about Christchurch. Notably, rainfall totals were under 20 percent of January normal amount, across much of the North Island,as well as in Nelson, Buller and Marlborough. An exception was seen in southern Hawkes Bay, with persistent rain between 14 and 16 January resulting in double normal January rainfall there. The far south of the country also recorded useful rainfall, as occasional cold fronts penetrated inland.

January saw well above average temperatures across New Zealand, with a significant 5 day heatwave to end the month. Very warm air from Australia resulted in widespread and sustained heat, with an additional boost of strong Foehn warming across the Southern Alps. Temperatures peaked at 37C in the eastern South Island on the 31st, with many Marlborough, Canterbury Plains,and inland South Island locations, as well as Napier, recording 35C or more during the heat wave. Records tumbled in Wellington (Kelburn), Northland (Kaitaia),Waikato (Hamilton Airport) and Manawatu Wanganui (Levin), with these stations experiencing their all time hottest day on record. The inland Bay of Plenty,inland Wairarapa, Marlborough (excluding the Sounds) and parts of the Canterbury Plains exceeded 5 day heatwave thresholds.

January was a sunny month for many, with Richmond (Nelson) setting a new record for the sunniest month ever recorded in the South Island. As the data for Richmond only goes back a few years, it is good to confirm with Takaka, which also saw its all time sunniest month. Nelson Airport observed its second sunniest month on record.

The Ocean

El Nino conditions remain 'on hold' in the tropical Pacific Ocean.Seas remain warmer than usual along the equator, but the atmosphere has failed to play ball.The Southern Ocean has shown a preference for its settled phase in January,although forecasts show this diminishes during February. Sea surface temperatures in the Tasman Sea and around New Zealand remain well above average,running between 1 and 3 degrees above normal. Strong winds mid month did produce a brief pause in this warming, but intense High pressure at the end of the month meant sea temperatures climbed again.

The February 2019 Outlook

High pressure remains in charge for the first week of the month, continuing the drier than normal flavour. However, a pattern shift towards low pressures in the New Zealand region for weeks two and three (11-24 February)is signalled.Westerlies may return across the country for the last week of the month. The net effect of this switch should be more rainfall than was seen in January for all regions of the country. Expect above normal February rainfall for the West Coast South Island, with near normal February totals for all other regions. Note that rainfall predictions in February show less skill than at other times of year.Also, since February is climatologically a relatively dry time of year, even near normal tallies may not be large.

Temperature wise, the heat contained in the seas around New Zealand is expected to be a factor initially, with above average temperatures forecast next week(4-10 February). However, predictions show a return to 'near average' February temperatures for the remainder of the month. This means that January monthly temperatures may exceed February monthly temperatures - an uncommon situation.

Given it is the hottest time of the year for most regions, even 'near average' February temperatures will still yield hot days above 25C at times.

Bottom Line

After a hotter and drier than usual start to the month, some relief is forecast for farmers in February. A pattern change is signalled in the second week of the month, bringing better odds of rainfall, and closer to average February temperatures.