A little science on why last night was’nt even close to UK’s coldest of winter despite a seemingly good set-up

On the face of it last night looked promising to be the UK’s coldest night since February 2012 when it hit -15.6C at Holbeach, Lincolnshire. This winter has had it’s share of chilly nights, hence -13C in the Midlands, -8C in Glasgow but last night appeared to support the most conducive atmospheric conditions to present us with the coldest night of winter 2017-18, surpassing that of -13C set in early December in Shropshire.

So why did it only get down to -10C at Dalwhinnie?

Credit: Met Office

I put it down to a few factors.

  1. the strengthening high was only just settling overhead mid evening which lost the first few hours of cooling due to wind blowing which causes mixing.
  2. The air cooled off daytime highs largely above freezing
  3. Finally when winds lightened up, the temperature dropped well below freezing but this cooling process was cut short by patchy cloud cover.

Note the core of HP only just moving over NW Scotland after dark.

Credit: Meteoceil

So the breeze which blows counterclockwise around this high was stopping the temp from falling.

Had it not been for the cloud and despite the breeze blowing into late evening, we probably would’ve approached the season’s low.

Tonight may have a better shot was lower base temp at sunset, high firmly in place and so there’s no mixing.

Sun is just setting here in Edinburgh and the cooling process has already resumed with nice 1033mb high pressure across Scotland.

Credit: Meteoceil

Current temps

Credit: Meteoceil

Tags: , , , ,

Follow us

Connect with Mark Vogan on social media to get notified about new posts and for the latest weather updates.

Subscribe via RSS Feed Connect on YouTube

Leave a Reply