Drought next year in Northland? Depends what you mean by drought

The 2013 almanac mentioned potential for drought in Northland. With the 2014 almanac now in production we have warned that for 2014 the country could expect intense summer heat at times, but rain intermittent enough to avoid widespread drought. In the summer of 2014 rain north of Auckland may be up to 50% below average, so will need to be well utilised. Northland will be the region most affected again, because of stronger northerly heat.

Heavy rainfalls will come for Northland in the first week of all months between January-September. For first three months these should be overnight events. Closer perigees in January will ensure summer heat but which will dry rain quickly. With no long runs of rain-free days early in the season and rather low amounts when showers arrive, the situation needs to be managed. Bad management will result in drought calls.

It is therefore approaching time to consider dryness that may inconvenience Northland farmers because the region can expect to be drier than average for most months in the first half of 2014. Although there may be interspersed wet spells, there will overall be less rain than average for the times of year.

The question is whether or not farmers themselves will be calling it a drought. How long do places go without rain before making the drought call? A loose international definition of drought is the passage of three weeks with less than one third of expected precipitation. In the UK an absolute drought is at least 15 consecutive days on none of which is there more than 0.2 mm of rainfall.

Six days without rain in Bali is drought but would not be considered so in Libya, which gets annual rainfall less than 180 mm, and drought there is declared after two years without rain. In Ireland drought is 20 days without rain. In NZ, according to NIWA, drought is a rainfall deficit that restricts or prevents a human activity, something up to MAF to declare and so has a political component. Of course all these arbitrary definitions give no indication of the impact of drought.

In Northland in the first half of 2014 it is going to be drier than average but not completely dry. As usual some places will be drier than others but we cannot monitor the many locations for which historic data is unavailable. That means it is possible for some areas to have full-blown drought which we could miss. We are all familiar with the childhood delight of discovering rain falling on the next paddock and not where you are standing.

So within a relatively small area one location can end up getting drought whilst neighbours get all the rain. An example further south was that Horowhenua stayed largely green whilst surrounding districts had standing brown pasture. A lot of droughts are created by man because we have altered the ecosystem by removing trees, making barren landscapes easier to plough but also creating greater run-offs that prevent soil soakage.

Rather than the drought word for next year, we have opted for drier than average for Northland but not severe enough to warrant drought action by MAF. If farmers are willing to be cautious to conserve rain received, particularly around the Christmas and New Year period when campers are going to get washed out on their holidays, then farmers may be able to protect themselves against the effects of drier months to follow.

Too often with severe weather, fears mount that a destructive current pattern is here to stay; the so-called climate change. This is the lie that media and alarmist earth scientists have circulated, the idea that any unusual or unexpected weather is the initial stages of the next Armageddon, rather a return leg of a long established cycle. Green ideology has generated a panic mentality to fight against and repel Mother Nature in some imagined nature-versus-us competition for the farm.

So what to expect? The Xmas-New year period should be fairly wet. Between 15-20 January there may be sprinkles of showers in the far north for Kaitaia and Cape Reinga but not for Russell, Dargavile and Whangarei. Depressions will pass over the top but should not reach Warkworth or Maungaturoto. In the last 10-days of January after a relatively dry spell of almost two weeks there may be good rain in Kerikeri with possible flooding for Kerikeri and Russell.

In February there may be enough spotty showers to cause facial excema and fly-strike in sheep. Irrigation would be a good idea around 10 February and again around 18th to take advantage of intermittent heavy falls. More showers come on 22 and 28 February. Dargaville may be the driest district in February, with only about a third of the January rain average.

In March the first week is likely to be wet followed by good rain on 13th, but then only light and patchy showers for the remainder of the month. Dargaville has a fairly dry March with twice the monthly March average mostly from only two rain days, the 4th and 13th. Any rain after the midmonth may be too light to be significant.

In April there should be regular showers throughout Northland with the heaviest falls in the second week and at the start of the fourth week, but overall only half the monthly average. For May, rain begins the month, then five days of dry spells are followed by three or four wet days, this pattern then repeating. June rain is intermittent for the whole month apart from a dry few days around 12th-15th and after the 26th.

Northland farmers will be delighted with early summer heat and moisture and the increased pasture growth, but less than pleased with the subsequent drier months. With good management and conservation drought and/or the effects of that later dryness can be avoided.

Ken Ring of www.predictweather.com is the author of Weather Almanac for NZ for 2013