Thursday 14th January 2021

The battle between cold and mild continues – though cold will mostly win for now. Expect a bit of everything that is usual for the time of year over the next week or so – and yes, there is another marginal rain/snow event…the joys of forecasting!

No photograph this week.

It will be fairly cloudy tonight, any early light rain will fade, a frost in places, the odd pocket of fog, but mostly just cloudy and cold. Down to around 0’C, some ice possible.

Friday starts rather cloudy, but with some brightness. Cloud generally will lesson, more in the way of sunshine, albeit hazy as the day goes on. Cold, 4’C. A frost at first overnight, down to around -2’C, but temperatures pick up a tad overnight as cloud thickens with some light…rain…arriving before dawn as a weather front arrives.

Saturday sees this weather front bump into the cold air, and it is certainly possible that we see a spell of 1-2 hours of sleet or snow in the early part of the morning, perhaps a temporary slushy covering. Very marginal, as it always has been this winter, but I think more likely than not. It will turn back to rain fairly quickly, and clear by mid/late afternoon. Around 6’C by time the rain has cleared. Variable amounts of cloud overnight – probably too much cloud for a frost, down to around 2’C.

Sunday sees a ridge of high pressure over the UK. Some sunny spells, albeit generally quite hazy. 6’C. Variable cloud overnight, a frost in places – down to 0’C, give or take.

Monday sees low pressure approaching from both the south-west, and north – the former with the mild air and the latter with the colder air. The milder air wins this time.

Monday itself looks dry, some sunshine, some cloud. Sunshine generally rather hazy. 6’C. Overnight sees some rain, freshening winds, and a tad milder, 8’C.

Tuesday looks windy with rain at times – some heavy. Some dry spells in between. Windy in a fairly mild south-westerly – 10’C. Outbreaks of rain still possible overnight – uncertain as to when the low pressure clears east.

For Wednesday, a cooler flow from the north-west takes back over. Sunny spells, probably dry – just a very small chance of a stray shower, around 6’C. Breezy also. Chilly overnight – at the moment it looks most likely to be too windy for a frost. Around 2’C.

Thursday looks cool and windy – sunny spells, a small chance of a stray shower. Around 6’C.

Probably cold or fairly cold for Friday and into next weekend.

That’s about as far as I can go with reasonable confidence – everything is very much up in the air for medium-term weather forecasting thanks to the sudden-stratospheric warming event from 5th January, which is still not fully resolved or understood in terms of its implications for the troposphere (our level of the atmosphere).

What I do know is that the polar vortex did not split – like it did in 2013 or 2018 – it was merely displaced and significantly weakened.

So my best reading at the moment is that the chance of a “Beast From The East” type event is low. However, the chance of further cold weather from the north, similar to what we’ve been seeing over the last few weeks is quite reasonable.

Generally, I think the most likely outcome for the next few weeks is something similar to the current pattern of cold weather trying to push down from the north, milder air (with rain) pushing up from the south-west. Where the two air masses meet, there will often be significant snowfall but that is more likely to be north England or Scotland – but it still could happen at our level.

I’d suggest therefore that wetter than normal is most likely in the medium term, and generally becoming milder more often as the pattern tends to shift north – to the point for the latter part of February where we are fairly dry and probably mild, with the rain to our north.

There is high uncertainty however, so I’m low in confidence. I’ve seen model output with 14’C daytime temperatures for 2 weeks time – and also output with -5’C daytime temperatures! Make of that what you will. My assumption is that the SSW is playing havoc with the models, and I’m not too trusting of them at the moment.

I do also have a suspicion that the SSW may imprint on our weather patterns into spring, and lead to more northerly flows than normal – ie more cold weather in spring. Sorry. But as I said, very low confidence of anything going into the future.

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