Brits are set to bask in some of the hottest temperatures of the year so far, thanks to the little-known ‘Foehn effect’ but things are set to take a turn for the chilly again before the end of March
Brits are in for a weather rollercoaster in the coming days with the hottest weather so-far this year giving way to snow flurries, according to forecasts.
Wednesday is set to be the warmest day of the year so far, with temperatures expected to reach around 21C, the Met Office has said but temperatures are set to plunge before the end of the month, forecasters have warned.
In some parts of the UK temperatures could be as much as 9°C above the average March temperature, making for an early spring scorcher for many. Scotland has seen its warmest day of the year so far on Tuesday with a maximum temperature of 16.1 degrees recorded in Lossiemouth.
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The previous record temperature this year came on March 5 when 19.2C was recorded in London. But tomorrow could see it beaten if the mercury touches 20C amid the predicted warm spell.
The unseasonable weather is thanks in part to a weather phenomenon called the ‘Foehn effect,’ forecasters have said. Parts of western Wales and western England could see highs of 18C to 20C on Wednesday afternoon due to the Foehn effect, Dan Harris, Chief Forecaster at the Met Office said.
This little-known phenomenon occurs when moist air is forced up one side of a mountain where it cools, leading to rain or snow. But as the air goes over the top of the mountain and down the other side it rapidly warms, leading to high temperatures on the downward slope.
Mr Harris said Wednesday would likely see the warmest weather so far this week, with parts of west Wales and western England seeing the mercury rise to 18-19C, he added “possibly even 20C is on the cards”.
“This is due to the additional boost expected from the passage of east to south-easterly winds over areas of higher ground, known as the Foehn effect.
“There’ll be a big diurnal range this week, which is the difference between the maximum daytime temperature and minimum overnight temperature.
“Thanks to the clear skies during the day, we’ll see some chilly nights after the warmer days with a few places experiencing air frost.”
Meanwhile the hot weather is not set to last, with forecasts for snow later on in March. According to predictions from WXCharts.com northwesterly parts of the UK are set to see flurries of the white stuff on Tuesday March 24.
This dramatic shift is not uncommon, with unsettled spring temperatures often tipping back and forth around this time of the year.
The long range forecast from the Met Office for the period from Sunday March 22 to Tuesday March 31 said: “A transition to a more changeable and in places rather unsettled spell of weather looks to take place at the start of this period as Atlantic frontal zones cross the UK.
“These are likely to be most active in the north and somewhat weaker further south, closer to a ridge of high pressure extending northeast from the subtropical Atlantic. It is possible that we may see a briefly widely colder interlude with northerly winds during the final week of March, which would bring the potential for some snow, especially for northern areas.
“Widely strong winds could also develop around this time. By the end of March, high pressure may become rather more dominant with plenty of dry weather, but with some overnight fog and frost.”
