EMAIL EXCLUSIVE: John Hammond’s Month Ahead – Winter? No, it’s just a dress rehearsal
Flying in from the warmth of Gibraltar, I think I might feel the shock of this weekend’s cold snap more than most. Oh, and the clocks go back too! Still – I wouldn’t want it any other way! It’s a peculiar and interesting time. Why? Because this short sharp burst of northerly winds is the symptom of a larger-scale and longer-term discombobulation of the ‘atmospheric furniture’ (and you don’t hear that very often in your average weather forecast!). With the jet stream tying itself in contorted and slow-moving knots, long-range forecasts can struggle to unravel the complexity to give a clear and consistent direction. One signal that does show through is that our usual supply of westerly winds cannot be relied upon to bring our autumn back onto an even keel in the near future. Big swings lie ahead through November.
Chilly end to October
Wetter and milder to start November
Drier and colder weather returns later
MONDAY 29TH OCTOBER – SUNDAY 4TH NOVEMBER
Trying to keep the warmth in and the wet out
As some of you have been commenting on social media, if we were two months ahead, the weather charts for the days ahead would bring quite a severe wintry spell. But as both the Continent and the North Sea still retain some of late summer’s warmth, the northeasterly that crosses them to reach us will be merely chilly rather than bitter.
Still, the 20-degree days of earlier this month will seem a very long time ago. Rain-bearing weather systems will be converging on us from more than one direction through the early part of the week. So we can expect some particularly bleak weather. If you reach double figure temperatures, you’ll be doing very well indeed. ‘Autumnal’ or ‘Wintry’? You decide. One way or another, cloaks and hats (pointy ones if necessary) will be essential attire for Hallowe’en.
While the chilliest air will have been squeezed out by early November, the UK looks like being a magnet for wet weather. Bands of rain will tend to get marooned across us, as Atlantic westerlies and Continental easterlies vie for supremacy.
Despite the glow of the warm bonfire, waterproof and windproof layers will probably be needed as Fireworks celebrations approach.
A chill calmnesss on Armistice Day, perhaps?
MONDAY 5TH OCTOBER – SUNDAY 11TH NOVEMBER
Milder then chillier again
While the Atlantic jet stream normally succeeds in winning these battles and sweeping such ‘blockages’ away, this spell looks different. There is no convincing evidence that westerly winds are going to win this one! Instead, I expect high pressure to start to build across us, with two main effects. Firstly, on a positive note, the weather will start to dry out through this week; and secondly, after a milder interlude, we will begin to draw winds in from the Continent again. A chill calmnesss on Armistice Day, perhaps?
Just how chilly those winds are is another matter; but, initially at least, it probably won’t be as cold as the air currently reaching us.
There is talk out there of an early Sudden Stratospheric Warming (an event that caused last winter’s ‘Beast from the East’). Let’s not get ahead of ourselves! Any more detail would be fool-hardy at this stage, given the lack of clarity that computer forecasts are giving us. Hopefully they will begin to give a clearer signal soon.
Promises of widespread snowfall are far too premature
MONDAY 12TH NOVEMBER – SUNDAY 25TH NOVEMBER
Computer says: “I don’t know”
Some of those same computer models, hell-bent on a mild, wet and windy end to Autumn, have informed some other centres’ seasonal forecasts recently. So it will be very interesting to see whether they change their tune.
There are a number of factors which will determine the strength of the jet stream as winter approaches, and I talk more about these in our Early Winter Forecast. As it stands, the balance of evidence suggests to me that the jet stream will continue to be blocked from bringing a sustained Atlantic influence across us.
This being so, I expect a chilly mid-month period, with the wettest weather possibly focussed across the more southern parts of the UK. Promises of widespread snowfall are far too premature, but do make sure your windscreen scraper is unearthed again. It might be handy.
Gibraltar already seems a long way away…