Tonight is by far the coldest night of the season both here at my house where the temperature is now down to -6C while it’s a biting -10.2C up at Loch Glascarnoch in the North Highlands. The front which pushed through, heading south last night ushered in colder air with lower thickness values and with the combination of clear skies, light winds, fresh snowcover and those colder temperatures aloft, surface values are lower than any other night so far.

Despite the cold of tonight, our attention is drawn to the incoming weather system from the Atlantic. As this front slices into the cold stagnant air, the precipitation will turn readily to snow and initially to all levels. If you live in Northern Ireland, expect sleet, perhaps a rain, sleet and snow mix but snow will not be a factor until your over higher ground. Glenshane Pass may see a decent covering.

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Scotland

The Western Isles of Scotland shouldn’t expect much nor the immediate West Coast, however, if your inland where the cold air is stronger and to greater depth in the atmosphere, expect a period of moderate to heavy snow. The big question I am asking myself tonight is, how long does this snowfall last before a likely change to rain. The reason I ask that is because the longer it stays as snow, the greater the accummulation and potential disruption, especially if it starts from 1am Thursday onwards and say it continues till rush hour. By rush hour across the Central Belt, there could be a significant amount of snow which could cause travel headaches.

I expect anywhere from a coating to perhaps 2 inches across Glasgow and later in the morning, Edinburgh. Locally 3 inches is possible over hilly parts of both cities.

The higher parts of the M8 and M74 may see as much as 2-4 inches IF snowfall is heavy and it falls for a substantial 2-4 hours. This may cause significant issues as travel slows. Underlying ice could create a rash of accidents.

Some Highland routes are likely to be seriously affected with potential closures. The snow gates are likely to shut on such routes as Banchory to Fettercairn and Cockbridge to Tomintoul. Even main arteries such as the A9 could see near whiteout conditions with heavy, blowing snow as winds become strong. The M74 could be affected by very challenging driving conditions too with strong winds.

As the front sweeps through, rains will likely follow the snows and depending upon how long the precipitation stays as snow and how heavy it is, will depend upon how much snow remains on the ground following the backside rains. I believe many parts of the inland west of Scotland should still be white tomorrow night with a thick covering across higher routes of Ayrshire, D & G, Lanarkshire, the Borders and right up the East Coast.

If you live anywhere from Carlisle to Manchester, I believe you will see snow down to low levels. The greatest amounts of snow for low levels will be confined from Lancashire on north where a covering is highly possible. Down nearer to Manchester and although I think it snows for a time, it may be harder for a significant covering to develop as I think snow changes over to snow earlier than further north.

England

The higher ground of Cumbria, Northumberland, Durham down through Tyneside, Yorkshire and the spine of the Pennines could see significant amounts. Anything from a dusting to 4 inches is possible.

Like over higher, exposed routes such as the Trans-Pennines and across the North York Moors, perhaps even Snake Pass in Derbyshire, watch for very poor driving conditions as winds whip around the snow.

The models even show snow on the ground all the way to the Chilterns.

BTW, look for another very cold night tomorrow night with clear skies and lots of fresh snow cover which will help further cool the air overnight. This snow will keep coming days cold as the lower atmosphere is significantly refrigerated. Cold nights right through this weekend with penetrating frosts.

Below is the latest snow charts for tomorrow and into Friday.

Here’s the ECMWF Deterministic..

GFS

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