18.7C At Braemar, -5.6C At Katesbridge, It Must Be March

We’re at a seasonal cross roads, a time when the atmosphere wants to hold onto winter in the high latitudes but become summer in the low latitudes. The mid latitudes are in the battle zone between winter and summer. March is a fickle month, a month which can produce low 20s C as far north as Scotland like we saw in 2012 or -20s like we saw in 2010. This is the time when the atmosphere fights it out and therefore you can get a taste of all seasons, sometimes within a week, sometimes in a day.

seasons

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The atmosphere remains in a winter state with the mean air temperature only slowly warm, largely down to surrounding water being at it’s coldest. However, away from the cold waters of Atlantic and North Sea, the air heats fast, particularly so but the key difference is the MUCH higher and therefore stronger sun angle. With sun and little wind, the air warms nicely at this time of year.

Credit: Met Office

Credit: Met Office

Highland Glens are prime locations for the largest diurnal temperature swings in the UK as they act as a sun trap by day with no outside cooling influence.

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It’s opposite by night as that same dry air cools as fast as it warmed at the beginning of the day and with nights still relatively long with still a solid 10 hours of darkness, cold air drains down surrounding side hills and the cold collects at the bottom.

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CREDIT: MARK VOGAN

CREDIT: MARK VOGAN

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Yesterday’s satellite view.

Credit: NASA

Credit: NASA

This morning’s surface map according to the GFS.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Location of high pressure is key. In the last 5 or 6 days it’s been centred over the Faroe Isles and therefore winds circling counter clockwise has led to an onshore wind up and down the UK’s North Sea Coast.

Under brilliantly sunny skies and light winds, the thermometer reached 18.7C yesterday in Braemar (UK’s warmest to date) while 50 miles east along the North Sea Coast it was quite different!

Credit: Met Office

Credit: Met Office

With waters coldest at this time of year, air out of the sun is cooled to the level of the water and therefore the reason for areas stretching from Caithness to Kent has been misty, foggy and trapped beneath a bank of low cloud, a chilly wind and air temp of just 4-8C.

Where there’s gaps in the land such as the Central Lowlands of Scotland, this breeze and presence of low cloud and fog penetrates deeper inland reaching as far west as Glasgow but just miles to the north and south with protection from hills and mountains, the true presence and influence of the high is felt with cloud free skies and a noticeable warmth from the mid March sun.

Yesterday morning.

Credit: Meteoceil

Credit: Meteoceil

Yesterday afternoon.

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Strength of sun at this time of year allows strong surface warming to take place but nearer coastal waters and particularly with an onshore breeze, it still feels like winter.

Looking ahead to the weekend and it’s looking cloudier with less variation in temperature as the dominant high retrogrades westward.

There’s a level of uncertainty over next week as the GFS weakens and shifts the high south towards the Azores in which allows the Atlantic storm track to return.

The ECMWF has lost it’s cold solution from recent days and holds the high in place over the UK through mid next week before allowing Atlantic fronts to push in.

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

See today’s video.

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