Belfast is ‘wettest in the UK’ after thunderstorms break record heatwave

From breaking its all-time record for hottest temperatures three times last week, Northern Ireland today grabbed another less enviable record - as the wettest place in the UK.

Wednesday, 28th July 2021, 7:14 pm
Updated Wednesday, 28th July 2021, 7:18 pm

Belfast saw half a month’s rain falling in just five hours today, which came after a Met Office Yellow Weather warning for thunderstorms - the second in 24 hours.

Thundery showers on Tuesday broke the heatwave and and saw localised flooding in areas such as Belfast and Ballyclare, washing away happy memories from the previous week when temperatures soared to a record NI high of 31.4C.

On Tuesday Trafficwatch NI warned motorists to avoid a range of roads in Belfast due to flooding, including parts of Stockman’s Lane, Malone Road, the Castlereagh Hospital Road, and parts of Carryduff.

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Motorists were advised that the Lisburn Road in Belfast was blocked, due to a car stuck in floodwater. Picture By: Arthur Allison/Pacemaker Press.

The rain caused many parts of the centre of Ballyclare to flood with several local businesses forced to close, including Asda.

Met Office meteorologist Alex Burkhill said the heatwave that hit Northern Ireland last week was “exceptional”.

“There were no all time records broken anywhere else in GB in that period,” Mr Burkhill said.

“We had high pressure last week which brings fine, settled sunny weather and allows temperatures to rise.”

Usually, while warm air hitting NI often comes from France around July, this time it came up from Africa, he said.

“2018 was the last time Northern Ireland had temperatures above 30 - it only happens once every 5-6 years in Northern Ireland.”

However, almost as sure as day follows night, so do thunderstorms often follow such heatwaves.

“The warm moist air holds a lot of energy so eventually you will often see a thundery breakdown. And that is what happened in Northern Ireland.”

As a result the Met Office rain gauge at Belfast International Airport recorded 42.4mm of rain from 9am to 2pm yesterday (Wednesday) with thundery showers continuing for the rest of the day.

“The average rainfall for NI in July is 81mm for the month. So the fact Belfast recorded 42.4mm in one morning means it would be fair to say you have had a half a month’s worth of rain in just five hours.”

“That is a lot of rain for anywhere, particularly for a city like Belfast, so it is not surprising there have been localised impacts.”

He notes that England saw much more extreme flooding, with over 100mm falling in a few hours in recent weeks, with Derbyshire and parts of London suffering intense thunderstorms.

“But the wettest place anywhere in the UK today [Wednesday] has been in Belfast, and next was Craigston in Scotland with 35mm. Lots of places have seen heavy showers but Belfast seems to be the worst hit, at least according to our available rain gauges.”

He said Northern Ireland also saw some of the hottest temperatures in the UK this year, at 31.4C, coming seventh highest, with Heathrow reaching 32.2C.


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