From wet to dry as El Nino takes hold

Niwa’s daily climate map for yesterday, showing the fast spread of dry areas down the east coasts of both islands.

The region is on the brink of setting a new, ominous weather record, and it is not good news for those on the land.

With just a couple of days to go to the end of the month, this August could end up being the driest on record for Gisborne — and there is bad news regarding the development of El Nino.

This comes hard on the heels of the complete opposite situation, with super-wet weather over the first half of the year which broke the all-time record for  a full year’s rainfall.

Overnight Sunday/Monday saw a sprinkling which dampened the ground to the tune of just .4 of a millimetre.

That brought the total for the month to just 16.5mm, far short of the average for the time of year.

The latest 30-year “normals” put the August monthly average at 86.5mm.

The sudden dry means Gisborne has had less than a fifth of its usual rainfall, or just 19 percent.

Rainfall amounts have been insignificant over the past 30 days,  7.7mm being the wettest on July 28.

Gisborne’s driest August on record as measured at the airport is 23.7mm in 1982, when there was a very strong El Nino weather pattern.

That is the driest the area has experienced, including harbour records dating back to 1878, or 135 years.

The more alarming aspect is how quickly the weather has gone from wet to dry.

All the signs and latest scientific monitoring point to a rapidly developing El Nino.

The weekly bulletin issued by the Climate Prediction Centre (CPC) of the the US National Oceanic and Atmospheric Administration (NOAA)  says quite clearly that and El Nino is now under way.

This is based on satellite measurements of sea surface temperatures across the Pacific, and the CPC says there is now a “greater than 95 percent chance this El Nino will continue through December and into February 2024”.

For the Gisborne-East Coast region, the more disturbing aspect of the latest NOAA assessment is the greater confidence in a strong El Nino event leading into summer.

“Given recent developments, forecasters are more confident in a strong El Niño event, with roughly 2 in 3 odds of an event reaching or exceeding 1.5°C for the November-January seasonal average” in the key monitored area, NOAA says.

For this district EL Nino can bring more south-westerly winds and an intense El Nino raises the spectre of drought.

In the past few weeks there has already been a swing from north-westerlies to winds from the cooler southerly quarter.

Daily climate monitoring by New Zealand’s National Institute of Water and Atmospheric Research shows temperatures for the month are cooler by around half a degree.

The amount of sunshine for the whole Gisborne-East Cape region is also down, at about 85 percent of normal.

Lack of rain is the biggest impact of the month — and the daily climate maps show the rapid growth of dry zones from Coromandel, the Bay of Plenty, East Cape and down to Wairarapa.

The dry is also affecting the South Island’s east coast, with a severely dry patch in Otago all pointing to the swift onset of El Nino.