Rural Monthly Outlook:

Unsettled weather forecast to continue

Issued 1 August 2017

July 2017

Frequent lows were centred over New Zealand during July. Not surprisingly, the month was unusually volatile and very wet for most regions, excluding the West Coast of the South Island. Extreme weather events were characteristic of the month of July. An unusually cold outbreak on July 12/13 produced snowfalls to low levels across the South Island and also brought heavy snow to the lower and central North Island. Flooding rains occurred across the eastern South Island on the 21st, and State of Emergency declarations were issued for Otago, including Dunedin and Oamaru, as well as for Timaru and Christchurch.

The Ocean

Sea temperatures around the North Island coastline, as well as between Christchurch and Wellington, continue to run a touch cooler than average. In contrast, ocean temperatures around the lower half of the South Island remain well above average. Tropical waters to the north of New Zealand continue slightly warmer than usual.

Climate models are sticking with neutral conditions (neither El Nino nor La Nina) in the tropics through the remainder of 2017. For New Zealand, Tasman Lows and intermittent northwesterly winds will be far more influential on our weather maps during August.

The August Outlook

An unsettled, possibly extreme, August is predicted. Day-to-day weather maps during the month are predicted to be very busy, with frequent fronts and lows.Northwesterly winds and/or low pressures are likely to form the prevailing, or background, state. These are expected to produce a relatively 'warm and wet' flavour for most regions in August (especially the west-facing and north-facing regions of both Islands). Eastern regions of the country (Gisborne, Hawkes Bay,Wairarapa, Marlborough, Canterbury, Otago) and also Southland should still cop a fair amount of rainfall, most likely ending up in the near-normal range.

Temperatures in August are typically very changeable. However, the monthly average temperature is forecast to be slightly warmer than usual (average to above average) for most of the country. The notable exception is inland Southland and Otago, where near average temperatures are predicted.

Bottom line

An unsettled, possibly extreme, August is predicted. Northwesterly winds and low pressures are forecast to prevail over New Zealand, producing a wetter and somewhat warmer flavour to the month for most regions. The exceptions are eastern regions of both Islands, as well as Southland (with near normal rainfall expected); and Southland and Otago (with near average temperatures forecast).