Sun setting at Lake Ferry. PHOTO/EMILY GOODMAN
PAM GRAHAM
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Getting a good night’s sleep may be challenging for most of this week as temperatures are not expected to drop below 16C overnight when a sustained heat wave hits the region.
MetService meteorologist Rob Kerr said that as a rough guide, if a region has five days in a row with temperatures more than five degrees above a usual monthly average it is a heatwave, though in some countries the period
is shorter.
Taking Masterton as an example the average daily high temperature in January is 24C so a heat wave is five days with high temperatures of 29C or more.
The MetService 10-day forecast for Masterton had a high of 30C on Sunday followed by days of 31C, 33C, 33C, 32C and 31C.
Kerr said three things are coming together to create the heat wave – there is a big body of hot air “streaking its way across the Tasman Sea, which is itself quite warm”.
The Tasman Sea would usually cool the air mass down a bit but that is not going to occur and the hot air is going to park up.
“It sweeps across in a northwest flow, but a ridge of high pressure is sitting over the country preventing the hot air from being blown away,” he said.
“Right across the country we have these high temperatures predicted.”
Kerr said it would also be a quite humid air, so the overnight minimums will be 16C with stuffy conditions.
He said the airflow started arriving from midnight on Saturday night.
In Masterton, council officers make a decision about water restrictions each Friday. They met on Friday morning to assess the river flow and decided there was no need yet to initiate water restrictions.
“However, we need to reinforce the message things could change quickly this week and people need to keep an eye on the website for updates,” a spokeswoman said.
The water restrictions scheme has changed this summer and is instigated as a direct response to the water levels in the river.
When they drop below certain levels, different restrictions are instigated.
“In terms of our advice to residents, it’s the same messages we have been reiterating leading into summer regardless of water restrictions.
“We’re reminding residents that water conservation is important at any time of year, and especially when our rivers get low.
“We’ve been encouraging people to think about different ways they can conserve water around the home – playing their part and being water smart.
“For example, using grey water from the washing machine or shower to water non-edible plants.”
There are tips on the council website.
