No meaningful rain since September

WARM AND DRY: The National Institute of Water and Atmospheric Science (Niwa) is monitoring the Gisborne area among other drought hotspots. File picture

RIVER and stream levels are plummeting, irrigation restrictions loom over the Gisborne Flats and city water use has skyrocketed.

The Waipaoa River level has dropped to 0.859 of a metre at the Kaiteratahi Bridge, while Te Arai Stream has dropped by more than half a metre in the past few days to just .066m yesterday.

The Gisborne area is one of the drought hotspots being monitored by the National Institute of Water and Atmospheric Science (Niwa).

There has been virtually no rain for the three weeks since November 20, and the last really meaningful fall was on September 28, 74 days ago.

This year’s dry started two months earlier than last year, when low rainfall from November on saw the district in drought in the new year.

Fortunately, this year’s dry has been a cooler one, with the usual moisture-sucking hot north-westerlies displaced by easterly and southerly conditions, as the high pressure zones continue to track further south than usual for the time of year.

Nonetheless, evapotranspiration over the past week climbed to a daily average of 6.2mm, even though high humidity and morning dews have helped a little.

The soil moisture deficit now stands at around 140mm, which is definite drought territory, based on previous events.

Temperatures have been in the mid- to high-20s since November 24, and the region is currently baking in around 125 percent more sunshine than usual, along with most of the country.

The six last days of November averaged highs of 23.1, two degrees warmer than usual. The night-time lows averaged 12.8 degrees, again, two degrees warmer than usual.

So far this month the daily maximums have averaged just over 26 degrees, over two degrees hotter than the 30-year average of 23.2.

Night-time lows have averaged a degree warmer than usual at almost 14 degrees. Sunday night “cooled” to a minimum of 17.5 degrees.

Another boost to temperatures has come from the sea, which is warmer by up to six degrees in some places around New Zealand.

Yesterday the 1pm sea temperature for Gisborne was 18.9 degrees, a degree warmer than the average for this time of year.

The MetService forecast for the next few days offers nothing in the way of real relief except for perhaps a few light showers.

Meanwhile, it has now been acknowledged that weak La Nina conditions prevail and Niwa’s three-monthly outlook suggests current conditions will continue in the Gisborne-East Coast region.

Niwa says the Gisborne region has a 65 percent chance of weather being hotter than usual, with rainfall tending to be above normal (35 percent chance of normal, 40 percent chance of above-normal).

Soil moisture and river flows are predicted to have an equal 35 percent chance of being normal or above-normal.