Thursday 23rd September 2021

Well, it has been a pretty nice, sunny and warm September so far, and we can just about squeeze enough out for the weekend too.

A change to something more autumnal will occur on Monday – though changeable rather than outright unsettled.

Thanks to Claire for the photograph.

Tonight will see mostly clear skies, a small chance of some mist/fog by dawn in a few spots, down to around 11’C.

Friday sees high pressure remain in charge, though low pressure is not too far to our north.

Long spells of sunshine in the morning, some cloud will spread from the west during the afternoon but it will remain pleasant. Very warm, 24’C. Clear spells at first overnight but low cloud and possibly fog forming widely by the early hours, around 14’C.

Saturday starts dull and cloudy, perhaps foggy. This will take a while to break up and likely there will be spells of cloud for much of the day – but some sunny spells at times. A small chance of a shower, around 21’C. Clear spells at times overnight, though a small disturbance in the early hours may bring a shower or two – very hit and miss. Around 13’C.

Sunday is the last of the warm days. Sunny spells with variable amounts of cloud – a few scattered showers too, more likely during the morning and lunchtime period. Around 21’C. Cloud increasing overnight with rain by the early hours, some heavy bursts possible. A warmish and windyish night, 16’C.

Monday sees fresher air having spread across from the west.

The band of rain should have cleared by dawn, or will do a little after. Sunny spells and scattered showers will follow, around 18’C and breezy. Clear spells overnight, down to around 11’C.

Tuesday looks like sunny spells and showers. Perhaps a more organised band of heavy showers with hail/thunder possible – though details uncertain at this stage. Around 16’C. Clear skies overnight and chilly, down to around 7’C.

Wednesday is uncertain. The more likely outcome sees a spell of rain, the less likely outcome keeps it sunny all day. Around 15’C either way.

Thursday probably sees rain spread down from the north-west – uncertain on the timing so there could be sunny spells before and/or after. Temperatures somewhere between 12’C and 18’C depending on the timing.

Friday and into next weekend are uncertain on details, but looks like low pressure will be in charge, crossing to our north, but high pressure close to the south will have influence also.

Expect it to be windy but fairly warm, with at least one spell of rain in this period, and possible showers too – but also some bright spells too. Perhaps more likely back into the cooler air for Sunday.

Fairly low confidence – neither a washout or a warm, sunny weekend can be ruled out.

I do expect further warmer than normal weather after this short changeable spell – or as part of it, so October probably will end up warmer than normal too, and should settle down after this short changeable spell.

Looking further ahead, and my confidence for a colder than normal November and December is growing, the polar vortex is not forming in any meaningful way – similar to last winter – which will give higher chances of cold weather than normal.

Further to that, background signals remain supportive of a cold end to autumn/start to winter – and longer range models are already signalling an early season sudden stratospheric warming event.

I’m not sure how accurate such modelling is this far out, I don’t recall seeing an SSW modelled this far away.

But if one happens then it could be a notably cold November/December. Maybe make sure you have some alternative heating sources with the gas prices as they are!

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