Key Dairy Areas in New Zealand Forecast to Have a Drier Than Normal November and December
Latest ENSO update notes that neutral conditions are persisting but are forecast to change
Hamilton, New Zealand, 2 November 2018. The relatively benign seasonal forecast issued by ExtendWeather in October has
largely been experienced. Some much needed end of the month rainfall was experienced by many key pasture growing areas
and cooler weather has reduced the evapotranspiration rates. By updating three times a month ExtendWeather can offer
insights into occasionally rapidly changing seasonal forecasts for the country.
The latest forecast released this morning does show slightly to moderately drier conditions for some of the principle
dairy regions of the country, namely the Waikato down through Taranaki and the Manawatu, including a large part of the
Bay of Plenty and Southern Hawkes Bay. Across Cook Strait moderately drier than normal conditions are forecast for
Tasman, Nelson and Marlborough and down the West Coast and for much of the alpine country of Canterbury and Otago and
the western half of Southland.
The other key variable that can exacerbate drier than normal conditions at this time of year is temperature. Across
almost all the North island temperatures on average for the entire month of November are forecast to be very close to
normal to just slightly below normal in the eastern parts of the North island and very top of the South Island. It is a
different story for the rest of the South Island with alpine areas being between 1.5 and 2.0 degrees warmer than normal
with much of the rest of the island only up to0.5 degrees above normal.
Two other variables are forecast those being the potential evapotranspiration deficit and wind. IN the case of the
former slight deficits are forecast for nearly all areas of the country while the west coast of the South Island is
forecast to have the greatest deficits along with the Central Plateau of the North Island. Monthly wind runs for the
norther half of the North Island and Southern third of the South Island and up most of the east coast of the South
Island are forecast to be above normal. The central part of the country is expected to have a monthly wind run near
normal for this time of year.
The ExtendWeather forecast is updated every ten days. The most frequently updated seasonal forecast in New Zealand.
ExtendWeather uses an ensemble forecast and proprietary downscaling technology. The team also has a handy piece of
software for viewing the forecasts that can allow users to zoom into either their own assets or farms and save sites for
quick analysis with each forecast when released.
Seasonal forecasts are increasingly used for important decision making for not only dairying but also for contractors,
for example December is looking drier and slightly warmer than normal and this can impact not only pasture growth but
annual crop production. At this point in time the forecast does not show a return to the near critical conditions that
prevailed during December last year when rainfall decreased markedly from normal and temperatures spiked. Sea surface
temperatures around New Zealand are forecast to be only around 0.5 degrees above normal in contrast to last year’s 2.0
to 4.0+ degree above normal temperatures. Visit the ExtendWeather website to access the viewer and receive regular three
times a month seasonal update.