• 10 months ago
This is the Met Office UK Weather forecast for the next 10 days, dated 10/01/2024

Things will turn colder again over the weekend and next week could see some more widespread and potentially heavy snow but details at this range are uncertain.

Bringing you this 10 day trend is Met Office meteorologist Alex Deakin.
Transcript
00:00 Welcome to the Met Office 10 day trend.
00:03 Could be a juicy one, especially if you're
00:06 interested in snow.
00:08 It's turned a lot colder, as you've probably noticed.
00:12 And the jet stream is partially responsible for that.
00:15 This is the scenario at time of recording,
00:17 a very amplified jet stream, which
00:19 means it dips well to the south and then arcs way up
00:23 to the north.
00:24 And in this arc is an area of high pressure.
00:28 As expected, it's been dominating our weather
00:30 for much of this week.
00:31 And it's allowed things to turn on the chilly side.
00:34 What we're going to see over the next few days
00:36 is the jet stream becomes a little messier, less
00:40 well-defined, weaker in many forms.
00:44 And as I said, just a little bit messier
00:46 somewhat all over the place by the time we get to Monday.
00:49 But what's happening behind me is quite important
00:51 across North America.
00:52 So let's head there, because quite a wide and well-defined
00:56 jet stream here is splitting, bifurcating
01:01 is the technical term.
01:02 So one arm of it does still extend up to the north,
01:06 but another arm of it dips to the south.
01:08 And it's that which interacts with this area
01:12 of low pressure, which potentially brings us
01:15 some pretty interesting weather as we go into next week.
01:20 More on that in a moment.
01:21 First of all, let's get through the rest of this week.
01:23 So let's rewind the clock and come back
01:25 to this area of high pressure dominating at the moment.
01:28 With high pressure, the air is sinking and the winds
01:31 going round clockwise.
01:32 So drawing in quite a bit more cloud and moisture
01:35 from the North Sea over the next couple of days.
01:38 But with the sinking air from that area of high pressure,
01:41 it does keep things dry for the vast majority,
01:44 bar a few scattered showers here and there.
01:46 Notice this cold front is approaching.
01:48 More on that as we get into the weekend.
01:50 But generally speaking, with this high sitting
01:53 over us for the next couple of days,
01:54 the rest of this week, it stays nicely dry
01:57 bar the odd shower.
01:58 Stays chilly, but if anything,
01:59 temperatures will be ticking up a little bit
02:02 through the second half of this week
02:04 compared to the early part of the week.
02:06 And certainly in the south, not as frosty
02:08 because there will be a bit more cloud coming in
02:11 as that area of low pressure sinks to the south
02:14 and then away to the west.
02:16 So that's the rest of this week.
02:18 But what happens at the weekend is quite interesting.
02:21 We start to see that cold front we saw earlier
02:23 just pushing away the area of high pressure.
02:26 So it starts to drift away to the west.
02:29 That cold front probably not having much in it
02:32 in terms of wet weather
02:34 because it's bumping up against the high pressure,
02:35 but it's followed by another
02:37 and then potentially another one.
02:39 And it's certainly gonna be followed
02:40 by the winds coming down from the north.
02:43 Northerly winds obviously are gonna bring
02:45 some pretty cold air.
02:46 So I mentioned temperatures actually rising a little bit
02:49 over the next couple of days by day,
02:51 but we'll notice then a drop in temperatures
02:54 as these cold fronts introduce colder air from the north,
02:58 initially just across the north into Saturday,
03:01 but then becoming more widespread,
03:02 that colder air drifting right across the country
03:05 by the time we get to the end of the weekend.
03:08 These weather fronts, let's say,
03:09 will introduce more cloud and maybe a bit of patchy rain
03:12 and a little bit of hill snow,
03:13 but not a great deal as they sink southwards.
03:16 But as we get into the colder air further north
03:18 and the isobars squeeze together,
03:20 we're gonna see strong winds coming down from the north
03:22 and they will generate snow showers,
03:24 bringing that colder air.
03:27 And these snow showers could be fairly significant,
03:29 particularly when attached to those strong
03:32 and gusty winds as well.
03:33 The Northern Isles,
03:34 but parts of the north of the mainland of Scotland
03:36 could see some heavy snow showers during Sunday
03:39 and into Monday morning in particular,
03:41 maybe even grazing parts of Northeast England.
03:44 So some snow showers through the second half of the weekend
03:46 over northern parts of Scotland,
03:49 somewhat hit and miss, but nevertheless,
03:51 they could amount to some serious dumps in places.
03:54 And with that strong winds,
03:57 that's an extra hazard to contend with as well.
04:00 So certainly feeling cold comes Sunday
04:03 across the northern parts of Scotland once more.
04:06 The cold air in place there right across the UK
04:07 by the end of the weekend,
04:09 but then our attention will be drawn
04:12 to what's going on out in the Atlantic.
04:14 And that area of low pressure we saw earlier,
04:17 there's a lot of warmth tied into that area of low pressure,
04:20 but also as it's developing out in the Atlantic,
04:23 there'll be a lot of moisture.
04:24 So quite a lot of rain tied into it too.
04:27 Now, remember the process,
04:29 the progress of this area of low pressure
04:32 is gonna be influenced by what's going on in the jet stream.
04:34 Remember it's splitting behind me there
04:36 across North America,
04:39 and it's the southernmost arm of it,
04:41 which then interacts with this low,
04:43 which will eventually then push it towards the UK.
04:46 But it's quite a complex situation
04:48 and exactly when and where it drifts up towards the UK
04:53 as we go into next week is the big question mark.
04:57 Before it does,
04:58 there's also the potential for more wet weather
04:59 to come into Northern Scotland.
05:01 So we don't lose to have that northerly flow by Tuesday,
05:04 the possibility of more wet weather coming in here.
05:06 And that could generate some more snow
05:08 over Northern Scotland as well.
05:10 So we need to keep our eyes on that.
05:12 And then from midweek onwards,
05:14 eyes down to the Southwest
05:15 and just how this area of low pressure approaches the UK.
05:20 And the computer models are handling it differently.
05:22 As you would expect,
05:23 we're a week away
05:25 and there's all those complex interactions
05:27 with the splitting jet stream to deal with.
05:31 I'm gonna show you what the American model wants to do,
05:34 the GFS with that milder air coming up from the Southwest,
05:39 bringing the milder air,
05:40 but bringing also the moisture.
05:42 And it's the boundary
05:44 where that moisture from the low pressure
05:45 hits the colder air that could generate some snowfall.
05:49 Now this is the American model
05:50 at midnight start of Wednesday next week.
05:54 And then this is the situation by midday.
05:57 So it's keeping the milder air mostly to the South
06:01 and that boundary between the milder and the colder
06:03 where they clash.
06:04 That's where we are likely to generate some wet weather,
06:07 a mixture of rain and snow in this scenario.
06:11 But the European model
06:13 is doing something slightly different.
06:15 The same kind of general setup
06:16 with low pressure approaching from the Southwest,
06:19 bringing the milder air,
06:20 but this is a little further North.
06:22 This is midnight into Wednesday.
06:25 And then by midday on Wednesday,
06:27 there's the low much closer in.
06:30 The warmer air is further North
06:31 and that boundary is further North
06:33 and quite a wide area of some rain,
06:36 but the crosses on here indicating snowfall.
06:39 So that would generate quite a bit of snowfall
06:41 in this scenario.
06:43 Now looking at one computer model run,
06:45 as you know, if you watch the 10 day trend regularly,
06:48 it's not really how we deal with the weather
06:50 in that longer term.
06:51 The models are run many times
06:53 in what's called an ensemble forecast.
06:56 And that gives you a range of potential solutions.
07:00 And that's what's showing here.
07:01 I love showing these spaghetti plots.
07:03 Again, as I've said before,
07:05 it's not my three-year-old's drawing.
07:07 This is generated by the European model.
07:09 And it's interesting to show these red lines in particular.
07:13 The UK is on the here.
07:14 I'll zoom in and show it perhaps a little clearer.
07:18 You can just about make out the UK now.
07:20 And each of these red lines is indicative
07:23 of when you run the model another time,
07:26 where the warm front is lying.
07:28 So where that boundary is between the warm air
07:31 and the cold air,
07:32 where we're likely therefore to see some snow.
07:35 And when you run the model many, many times,
07:37 you get the different scenarios.
07:38 Again, it's not completely clear, not obvious to see,
07:41 but some of those red lines are up across Northern England,
07:44 Southern Scotland.
07:45 Most of them are actually down across the Southwest.
07:48 And the main model run, the deterministic,
07:52 is shown there in the gold line.
07:53 That is further South.
07:54 But actually, most of them are further South still.
07:58 So there's quite a bit of a range,
08:00 a spread, as we say, of possible scenarios
08:03 for where that weather front is likely to be
08:05 for next Wednesday.
08:07 Here's a kind of schematic view
08:09 of what I've just been talking about what's going on.
08:12 That low pressure is very likely to be heading up
08:14 from the Southwest and bumping into the cold air
08:18 somewhere across the UK.
08:20 On its Northern flank, we will see some snow
08:23 where the moisture hits the cold air.
08:25 Then further South,
08:27 because that low is bringing relatively warm air,
08:29 it will be turning back to rain.
08:31 But it's where this boundary is
08:33 and where this snow fall,
08:34 that's the big question, if you like.
08:37 And as you might imagine,
08:38 there's a lot of uncertainty, as we've seen.
08:40 There's different possible scenarios.
08:43 It may be that the low stays to the South
08:46 and we actually don't see very much snow at all.
08:48 The UK just stays in the cold air
08:52 as we go through the middle part of next week.
08:54 This is an unlikely scenario, but it is still possible.
08:57 Another unlikely but still possible scenario
09:00 is the low is much further North,
09:01 much more developed,
09:04 and the snow risk would then extend
09:06 into parts of Northern Ireland and Southern Scotland.
09:09 The most likely scenario is for something in between,
09:12 but it's hard to say at this stage
09:15 where we're most likely to see the snow,
09:17 but somewhere in the zone across England and Wales,
09:20 that is the most likely scenario
09:22 for some significant and potentially disruptive snow
09:26 at this stage.
09:27 But this is a week away,
09:30 so pinning down details is not possible at this stage.
09:33 We will keep you updated.
09:35 Couple of graphs now to show you the uncertainty
09:39 and the disparity in uncertainty across the UK,
09:42 if you like.
09:43 These are the temperature trends,
09:44 the meteograms from the European model.
09:48 The top one is for Inverness
09:50 and the bottom one is for Southampton.
09:52 Again, we've shown these before on the 10-day trend.
09:55 The red blobs, box and whiskers plots,
09:58 show the maximum temperatures,
10:01 and you can see here the Southampton one,
10:03 the maximum temperature generally staying
10:05 below the average line, this red line here.
10:08 And same goes for Inverness.
10:09 It gets a little milder as we go through the weekend
10:12 with a bit more cloud,
10:13 but then another dip into next week.
10:15 Now, the key thing about the Inverness one
10:17 is that generally speaking through next week,
10:20 the main part of the box and whiskers plot
10:21 is below that average line,
10:23 indicating it's likely to stay cold,
10:25 at least until the very back end of the week.
10:29 But what I wanna show you here is the Southampton one,
10:31 how suddenly the boxes expand,
10:34 just emphasising that uncertainty, that range,
10:37 because this is the European model,
10:40 and we saw earlier with that spaghetti plot,
10:42 if that warm front is further north,
10:43 that would bring pretty mild air to Southampton,
10:46 whereas if it stays further south, it would be cold.
10:49 So there's a lot of, again, spread,
10:51 a lot of uncertainty in the temperatures
10:54 as we go through next week.
10:55 And of course, the temperature is crucial to the phase,
10:58 to the flavour of the precipitation that we see.
11:01 Will we see rain?
11:02 Will we see sleet?
11:03 Will we see snowfall?
11:05 Another way of showing that is looking at a different plot.
11:09 This is showing the temperature for Exeter,
11:12 not at the surface, but about a kilometre,
11:14 kilometre and a half up through the atmosphere.
11:17 And again, running the model many, many times,
11:20 and each of these dotted lines
11:21 represents a different one of those computer model outputs.
11:25 The strong pink line is the deterministic model,
11:30 the main model run, if you like.
11:32 And that is showing that, yeah,
11:34 it's gonna get a little milder
11:35 over the next few days into the weekend.
11:37 Then those cold fronts come south,
11:39 and the cold air gets into Exeter
11:41 by the end of the weekend,
11:43 staying cold the early part of next week.
11:45 And then in the European model,
11:48 the main model run brings that milder air in
11:52 across into the Exeter area.
11:54 But notice there are a lot more of those models
11:58 which keep the colder air in place in the Exeter area.
12:03 So that's why there is quite a bit of uncertainty.
12:06 Again, this is a week away,
12:08 so nothing too unusual about this amount of uncertainty
12:11 at this stage, but obviously it is crucial
12:14 for determining exactly where and exactly when
12:17 we will see snowfall.
12:18 Now, I've mostly been talking about the scenario
12:21 through Wednesday, Thursday next week,
12:22 but that's not, again, definite with that uncertainty
12:27 with the jet stream and where that low is.
12:29 It might not just be one low that we see coming in,
12:32 bringing the potential for snow in parts of England, Wales.
12:36 It could happen a couple of times.
12:38 And this is the scenario for Friday,
12:41 the most likely scenario for Friday of next week,
12:44 suggesting these numbers here that the air
12:47 will still be cold, below average temperatures,
12:49 and that low pressure may again be threatening
12:52 to come up from the Southwest.
12:54 So it's not just uncertain about exactly how far North
12:56 or how far South, it's exactly when we see
12:59 these low pressures coming in that's also open
13:02 to doubt at this stage.
13:04 But again, nothing unusual about that.
13:06 We're talking now 10 days ahead.
13:09 So just giving you the heads up that next week,
13:12 there is a reasonable chance
13:14 that at some point we could see some significant snow
13:17 across parts of the UK.
13:19 But right now, it's too early to say where,
13:21 it's too early to say when.
13:23 So please stay up to date
13:26 with Met Office weather forecast.
13:29 Easiest way to do that, hit subscribe on the YouTube channel
13:31 but of course, remember, we are always right
13:34 across all the social media channels as well.
13:37 [BLANK_AUDIO]

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