Why is NI getting such extreme heat: Met Office meteorologist explains that it’s all about the jet stream

The reason for the extreme heat in Northern Ireland is the jet stream bringing high pressure farther north and west than usual for this time of year, according to Met Office meteorologist Simon Partridge.
Press Eye - Belfast - 22nd July 2021

Northern Ireland continues to enjoy high temperatures as the warm weather continues  The Met Office has given an Amber warning for the area with an all time high temperature recorded in Castlederg at 31.3°C.

People enjoy the beach at Portavoe in Co. Down. 




Picture by Jonathan Porter/PressEyePress Eye - Belfast - 22nd July 2021

Northern Ireland continues to enjoy high temperatures as the warm weather continues  The Met Office has given an Amber warning for the area with an all time high temperature recorded in Castlederg at 31.3°C.

People enjoy the beach at Portavoe in Co. Down. 




Picture by Jonathan Porter/PressEye
Press Eye - Belfast - 22nd July 2021 Northern Ireland continues to enjoy high temperatures as the warm weather continues The Met Office has given an Amber warning for the area with an all time high temperature recorded in Castlederg at 31.3°C. People enjoy the beach at Portavoe in Co. Down. Picture by Jonathan Porter/PressEye

Mr Partridge explained: “Weirdly, the heat is all that bit further north and west than what we usually expect.

“It is to do with the jet stream. The jet stream is very far north at the moment, so it’s been well and truly buckled across from America, over the Atlantic, which has sent it really far north. It’s in Iceland at the moment, which has allowed this really big area of high pressure to move up – which is kind of normal for the summer for high pressure to move north to the southern parts of the UK and the southern parts of Ireland.

“But it’s just that bit farther north and west than usual.”

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He said Northern Ireland is almost in the middle of an area of high pressure at present, which has led to the extreme weather conditions.

“Really, it’s mainly centred not far off Northern Ireland,” he said. “You’re kind of right in the middle of that high pressure which has meant really, really light winds. That has allowed those temperatures to build up. Plus, it’s been there for a good spell now and it’s obviously there at the time of year when the sun is at its strongest.”

He continued: “So you have really strong sunshine, really light winds, and it’s been there for the best part of a week.

“That allows the ground to warm up quite a lot. You’ve also had really, really mild nights so the ground has not cooled down very much overnight. So each day it’s starting at a higher temperature, so each day just gets warmer and warmer.

“Basically, that’s what happens.”

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Moving on to the days ahead, the weather expert said: “There’s a really good chance the record might go again tomorrow [Friday] because all the indications are that it might be a smidgen warmer than it was today.

“What usually happens is that all those same things happen, but it’s usually farther south and east. So it’s usually sat over northern France and south east England.

“As we go into the weekend, we get low pressure pushing in from the south west and that basically shoves the high pressure out of the way a little bit.

“What will happen is the wind direction changes, and it comes around to more of a north westerly. There will be a bit more in the way of wind than what we’ve had in a while.

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“By Saturday, there will be a noticable change. We’re going to be back down to mid-20s, but staying pretty good. On Sunday we’re going to be around the same.

“By the time we get to Monday, it’s not going to be cold, but maybe in and around 18-21.”