Friday 5th January 2024

The rain is over for a while, time to look east and then maybe north, as colder and drier weather develops.

Thanks to Marion for the photograph.

Friday looks rather cloudy due to the overhang from the day before’s rain. There will be a bit of brightness at times, and also the odd shower – both more likely in the afternoon. Around 7’C. Fairly cloudy overnight with a little showery rain possible, down to around 3’C.

The general picture for Saturday sees high pressure starting to build around the UK, and an easterly starting to form.

Saturday again looks fairly cloudy, though there will be some bright/sunny spells at times – and a bit of occasional light rain. Feeling colder, around 5’C, maybe 6’C. A mixture of cloudy spells and clear spells overnight – a frost in places, down to around 0’C with enough clear spells. An outside chance of fog forming.

Sunday should see more in the way of sunny spells, but it will be cloudy at times – perhaps a spot of light rain but more likely it stays dry. Feeling fairly cold in the easterly breeze, 4’C. Uncertainty on cloud amounts overnight – a frost possible with enough clear spells, and temperatures somewhere between -2’C and 2’C.

Monday sees a mixture of sunny spells and cloudy spells, with the chilly easterly breeze continuing. Around 4’C. Probably enough clear spells overnight for a frost, down to around -2’C, give or take.

Tuesday looks much sunnier, though it will still be cold in the easterly wind, around 3’C. Uncertainty on cloud amounts once more overnight, a frost possible with enough clear spells – temperatures broadly somewhere between -3’C and 1’C.

Wednesday has a greater chance of cloud, though it will depend on exact positioning of the high pressure system and exact wind direction. Suggestions of it being slightly less cold, at around 5’C but still feeling cold in the easterly wind.

No real change for Thursday and Friday.

High pressure remains to our north, we stay in an easterly – but questions will remain over cloud amounts.

If cloudy, then overnight frosts unlikely. If not cloudy, then sunny spells by day but also overnight frosts. Generally on the cold side, though nothing spectacularly so.

Then what happens?

I’m not sure that I’ve ever seen so many signals, both shorter and longer term, all suggesting cold is more likely, than I do right now. Long-term we have an easterly QBO which means westerly winds are less likely in winter, plus El Niño winters tend to be drier and colder in the latter half.

We have a displaced polar vortex, we have a weakened stratospheric vortex thanks to an earlier Canadian warming event, and the current stratospheric warming event (which isn’t quite a major SSW but should impact anyway), we could still have a full-on SSW soon, the MJO cycle is in favour of a cold high pressure over the UK, and other factors I don’t especially understand such as angular momentum are apparently in favour, though I have to rely on the word of others for that. Plus the Met Office is signed up to cold.

Of course, our prevailing weather in the UK in winter is mild and Atlantic-driven.

Anyway, next weekend the more likely outcome sees our high pressure move west, perhaps north-west to Greenland.

This then allows two things – one an Arctic flow to set up from the north. But it could also allow low pressure systems to the south to get further north towards the UK.

I think, more likely the cold Arctic flow is the winning outcome – often sunny, snow showers possible though would generally need some kind of feature to develop, sharp overnight frosts.

However there is a scenario where the two meet – which on the northern edge would lead to heavy snow. It’s not likely but something to watch. Of course, the heavy snow could be further north, and we’d be in the milder air with heavy rain.

Where we go from there is uncertain, we need to sort out next weekend’s weather first – but I’d be surprised if this was our only cold spell. The cold spell could go on some time, with a chance of it being a very significant spell of cold weather – even if there may be a short break.

Interesting times ahead. Enjoy your weekend.

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