Weather: Thunderstorm risk for Bay of Plenty but Christmas looking favourable

Beachgoers make the most of the sun on Monday afternoon. Photo / Luke Kirkness

There is a risk of thunderstorms in the Bay of Plenty in the lead-up to Christmas but the weather for the jolly day looks to be better - at least on the coast.

A shallow trough of low pressure will cover northern and central New Zealand this morning, with the atmosphere becoming increasingly unstable as temperatures cool overhead.

Rotorua could expect mostly cloudy conditions with showers developing in the morning and thunderstorms from the afternoon, with downpours possible until evening. The high was expected to be 21C with a low of 12C.

Tauranga conditions were similar - mostly cloudy, with showers, possibly heavy with thunder, clearing in the evening, with a high of 23C and a low of 16C.

This week in the Bay of Plenty, the risk of thunderstorms will increase as daytime heating kicks in during the afternoons and into the evenings but MetService meteorologist Dan Corrigan said it was hard to say exactly where the higher risk would be.

“Thunderstorms are a very localised type of weather,” he said.

“The size of a thunderstorm covers a relatively small amount of space in the region so it could be that some people are affected by several thunderstorms and some people might not get any.

“The best tool is looking at the rain radar and seeing if any heavy rain is nearby that could have an impact.”

A thunderstorm risk would cover the entire region today, however, and Corrigan thought they were likely to pop up in a lot of places.

The entire week would be similar.

“[Warm temperatures] combined with other ingredients like high humidity near the surface and also the way that temperature changes with height as you go into the atmosphere, those are combining for the recipe of thunderstorms.”

Corrigan said it was hard to say where the thunderstorms would move but the ingredients were there and the risk was there that anywhere you are, a thunderstorm might pop up.

“As we get closer to the time, we will get a better idea of which places are more likely and which are less likely.”

The good news for Christmas was the forecast was pointing towards relatively settled weather.

“I know the forecast for the Bay of Plenty says showers with light winds but it’s likely that any showers will be a similar mechanism in the week leading up to Christmas. It’ll be more inland than near the coast in the places that heat up a bit more and looking to be less risk of thunderstorms,” Corrigan said.

“As we get closer to the time the forecast will give a bit more detail as to what people can expect. It’s certainly not looking to be a big rain-making weather system ruining everyone’s day.

“The models are coming in that high pressure is going to be the main player for Christmas.”

The forecast

Today

Rotorua: Mostly cloudy, showers developing in the morning. Thunderstorms from afternoon. High 21C, low 12C

Tauranga: Mostly cloudy, showers, possibly heavy, clearing in the evening. High 23C, low 16C

Tomorrow

Rotorua: Partly cloudy. A shower or two from late morning. High 23C, low 13C

Tauranga: Partly cloudy, shower or two late morning and afternoon. Light winds. High 23C, low 17C

Thursday

Rotorua: Partly cloudy, shower or two clearing late. Light winds. High 23C, low 12C

Tauranga: Mainly fine, odd shower. Light winds, becoming northerlies for a time. High 23C, low 16C

Friday

Rotorua: Partly cloudy, few showers, westerlies developing. High 23C, low 12C

Tauranga: Few showers with northwesterlies developing. High 24C, low 16C

Saturday

Rotorua: Fine. Westerlies. High 23C, low 12C

Tauranga: Showers, clearing and becoming fine. High 24C, low 16C

Sunday

Rotorua: Rain with light winds. High 23C, low 12C

Tauranga: Showers with light winds. High 23C, low 12C

- Source: Metservice as of 4.30pm Monday