Thursday 24th November 2022

More rain for the weekend, but becoming drier as next week goes on. And then colder?

Thanks to Chris for the photograph.

Tonight sees clear spells, a small chance of the remnants of a passing shower, still breezy and down to around 6’C.

The general pattern for Friday sees low pressure to our west, struggling to make much progress due to the monster high pressure over Russia – with a high pressure ridge building over the UK.

Long spells of sunshine, a bit of cloud later in the afternoon but otherwise a pleasant late autumn day. 11’C and breezy. Cloud thickening somewhat overnight, though maybe a few clear spells again towards dawn, down to around 5’C.

Saturday starts bright with some hazy sunshine. Cloud will thicken during the morning as the next weather front staggers towards us – though staying dry during daylight. Mild, 12’C. Patchy rain arriving early evening, and it will rain for most of the night, a few heavy bursts overnight possible. Still around 12’C – quite windy especially in the evening.

Sunday is uncertain – there is quite some uncertainty over how quickly the weather front clears. Maybe it clears by dawn – the less likely outcome, to be followed by sunny spells. More likely there is further rain in the morning, maybe even into the afternoon. Whatever the outcome, mild at around 12’C. We should see clear skies overnight, down to around 5’C ish – fog possible.

Monday may start foggy – uncertain. Broadly speaking once any fog clears, if there is any, will be some cloud, some sunny spells, a small chance of a shower – around 10’C. Uncertain on cloud/fog potential overnight – temperatures on the chilly side, though will depend on cloud amounts.

Really losing confidence on many details now, though Tuesday looks dry. Whether it is sunny, or dull and cloudy, is uncertain – with a risk of fog. Around 8’C.

I think that is about as far as I can go with any certainty. There is almost certainly a pattern change happening by now – a much weaker jetstream, a favourable upstream pattern for settled conditions – a huge high pressure block over Russia.

All of these factors, along with long-range modelling give me high confidence that December will be dry. Maybe some rain (or snow?!) on some days – but overall much drier than normal, and than it has been.

Exactly what kind of mostly dry and settled weather we transition to is very much up for debate, both short-term for the rest of next week, and longer term.

We could end up in a dull, drizzly and raw easterly (not quite cold enough out east for snow) for the rest of next week, or we could end up with high pressure over us – sunny with overnight frosts. Or some other similar combination. Daytime temperatures broadly in the range of 5’C to 9’C. That’s the general kind of theme anyway.

Certainly possible as December goes on, if everything aligns perfectly, that we see some snow. Possible. Nowhere near probable. It isn’t easy to get snow in December in the south of England, especially with warmer seas than normal and a not yet especially cold continent to our east. It would take something unusual.

But there are unusual background signals – the high pressure block to our east is unusually strong. The tropospheric Polar Vortex is unusually to our east. The jetstream is weakening.

It could happen. Things look interesting, but it’s a long way from interesting on weather models to actual wintry weather.

Time to watch Brazil vs Serbia. Have a good weekend.

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