A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.
Current weather trends indicate an autumn drought is a real possibility for the Gisborne region.
The latest satellite monitoring shows the current El Nino is starting to weaken. As it does so, the dry weather and winds delivering pain to the Canterbury region will move towards the North island.
Signs of the major shift are beginning to flash a warning — Gisborne has had less than one millimetre of rain so far this month.
High humidity and grey skies were forecast to bring a little rain over the past day or so, but failed to deliver.
On top of that, drying north-west and northerly winds which have been noticeably absent over recent months have started to return.
The track of high pressure systems across the Tasman from Australia have wreaked havoc with fires in the Canterbury region, but spared this district, with the fire danger yesterday low to moderate over the entire region.
Meteorological records show north-west winds are normally dominant for this time of year, especially during an El Nino event, but it is only now that they are taking over from easterlies and southerlies.
After a wetter than usual January, the change in weather patterns has seen the district’s moisture deficit climb rapidly.
As of yesterday MetService data showed the moisture deficit had passed the 125 millimetre mark.
The last decent rain was when 52mm fell over the last three days of January. At that point the moisture deficit was only 70mm.
The Gisborne region’s last drought was in 2020, which followed a dry second half of 2019. That drought finally ended in June, after 11 dry months out of 13 since the previous May.
This year follows the extraordinary record wet which saw the district get more than twice its average annual rainfall.
A dry year now would be bad news for those on the land still struggling from the damage of cyclones Hale and Gabrielle.
The wet drove vines and trees to respond with a large seeding and fruiting — a dry spell now would be another stress-load on plants.
The latest extended forecasts from MetService do not offer much immediate hope of rain relief — the outlook is for only a few possible millimetres to the middle of the first week in March.
Gisborne’s driest February on record (including harbour records dating back to 1876) was in 1946 when the instruments at the airport recorded a mere 2.8mm.
Since records started 148 years ago, Gisborne has had 12 Februarys with less than 10mm rainfall. On the other hand, last year set the all-time wettest February on record with almost 450mm.
Looking to what is happening with El Nino — much touted in the media as going to be one the strongest in recent times — the latest monitoring of sea temperatures in the eastern and east-central Pacific shows the warming is easing.
The latest analysis issued by the Climate Prediction Centre of the US National Oceanic and Atmospheric Administration says the “coupled ocean-atmosphere system reflects a weakening El Nino”.
The CPC statement says the data indicates a transition to neutral conditions by April/June, with “increasing odds of La Nina developing over June/August”.
For New Zealand and this district in particular, the ocean/atmosphere cooling should lessen the risk of sub-tropical cyclones.
A La Nina usually brings wetter, warmer weather to this region, so that could alleviate the possibility of a winter drought.
Meanwhile, daily monitoring by the National Institute of Water and Atmospheric Research (Niwa) shows February is delivering more sunshine than usual — currently 125 percent of the month’s average.
It is also warmer than usual — the mean daily maximum running at 26 degrees — 1.7 degrees warmer than the average. Overnight it is a little cooler than usual — just under 14 degrees against the February mean of 14.4. However, that means the daily mean temperature is point-seven of a degree warmer than usual.
Water temperatures off the beach are around a comfortable 20 degrees which is about right for the time of year.