It was another stunning day of cloud free skies. This powerful under ridge with surface pressure near 1040mb is completely supressing the atmosphere’s ability to produce clouds.

This was the view from space and notice cloud and sea fog is restricted to the West Coast.

UK view.

This was my view along the shores of the River Tay at Dundee yesterday afternoon.

My view Wed evening from the shores of Loch Linnhe near Fort William.

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Since this ridge is stronger than you’d typically see this time of year, the column of subsidence is deep and so that is why skies are clear throughout the day, the lack of moisture within this air mass has meant a large diurnal temperature swing with rapid cooling after an increasingly early sunset and rapid warming following sunrise. Where mist or fog has formed overnight, the warming process is slowed.

Overnight minimums have dropped to freezing, widely 3-6C outwith urban areas and where sheltered, plenty of mist and fog has been forming as the temperature meets the dew point. By day, mist and fog has burnt off or back to the coast through the morning thanks to the deep sinking under sunny skies quickly warms the lower atmosphere. By afternoon we’ve managed to climb into the low, even mid-20s, quite significant given the time of year.

A high of 23.6C was achieved a few days ago at Braemar, Aberdeenshire while places such as Tyndrum, Stirlingshire started off the day at -1C.

Yesterday’s high of 20.9C at Aviemore in the central Highlands broke an October record for the site which stood for exactly 30 years according to BBC Scotland Weather.

As heights lower, the depth of sinking lessens and therefore the atmosphere is much more able to produce clouds again and that’s why clouds will be back this weekend over the UK as heights fall from 1036 yesterday to 1028 today and 1018 tomorrow. This is also the atmosphere allowing surrounding weather systems to move in and by later Sunday into Monday, we have a system coming up from the SW and the same low which caused problems in the Med this week merging over southern England.

Check out the GFS pressure chart for the next 72 hours and notice the height falls.

Current

24 hrs

48 hrs

72 hrs

This change is kinda like going from Spain back to the UK without actually leaving.

Here we go, this is next week…

Also going to be closely watching Joaquin, currently a powerful Cat 4 hurricane lashing and likely devastating the Bahamas right now but it’s projected track may reach the UK within the next 7 days. Stay tuned.

See this morning’s video for the discussion.

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