10 Day trend - halfway through winter, any change? 08/01/20
As we approach the halfway point of Winter 19/20, are there any signs of change from wet, windy and mild? Met Office meteorologist Aidan McGivern has the 10 Day Trend.
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00:00Hello and welcome to the Met Office 10 day trend. We're approaching the halfway point
00:05of this winter and any snow lovers out there will be thoroughly disappointed so far. There's
00:09been very little of the white stuff at lower levels across the UK. It's often been mild,
00:15it's often been wet and windy. The question is, will it change? And the short answer is
00:20no, not in the next 10 days. It's likely to stay often wet and windy and very often, not
00:27all the time but very often, mild with it. The jet stream is going to continue to be
00:33very powerful but there are subtle hints of something a little different towards the end
00:38of next week. More on that in a moment. For the time being, we've got more low pressure
00:43heading our way through Wednesday night and Thursday. A lot of wind, rain and some hill
00:48snow for northern Britain. More details on that can be found through our short range
00:53forecast that can be found through the app and the website and YouTube channel. So we
00:57won't go into the details on Thursday's weather. Suffice to say, there's a lot of it. It does
01:02get out of the way though for Friday and then Friday, a brief, and I must emphasise the
01:07word brief, ridge of high pressure to bring a settled end to the week. A sunny day for
01:12many, the pick of the bunch during the next few days. It doesn't last long though because
01:17waiting in the wings, another powerful segment of the jet stream, the dark colours there
01:21indicating a particularly strong atmospheric airflow at 30,000 feet above our heads, helping
01:28to drive another area of low pressure in for the weekend and helping to stir up a lot of
01:34very mild and moist air from the south west which comes our way for Saturday. What does
01:40that mean? Well, it's pointed towards north western parts of the country on this weather
01:44front and that means it's a wet and windy start to Saturday for much of Scotland, Northern
01:49Ireland, Northern England and parts of Wales. And it's western hills where the rainfall
01:54will be heaviest and most persistent, particularly over the higher ground of Scotland as well
01:59as Cumbria. And for parts of Scotland, a yellow warning in force for rain, but there's also
02:04warnings in force for wind because the winds will be reaching gale force around exposed
02:08coasts of northern Britain, around hills as well, could cause disruption. So head to the
02:15website if you want more details on those wind and rain warnings. Not quite as unsettled
02:20for much of the rest of England and Wales, a cloudy day here, a breezy day as well, but
02:25a mild day many places in the double figures because of that wind coming from the south
02:29west. Fast forward to Sunday, it all clears through and we start off much brighter, but
02:35colder, certainly colder for northern Britain and with frequent showers coming into northern
02:40and western areas, well we're likely to see some sleet and snow building up across northern
02:44Scotland and not just over the hills, but some at lower levels. Hail in some of the
02:49showers as well, just about anywhere across western Britain because the showers will be
02:52particularly lively, but some sunshine in between, the best of which will be in the
02:56south east. We keep this strong westerly airflow going as we end the weekend and we keep the
03:03powerful jet stream running all the way across the Atlantic and picking up more areas of
03:07low pressure. Here's one, watch how the jet stream deepens it very rapidly for the end
03:12of the weekend and into the start of next week, and by this stage, really tight ice
03:16abats across western Britain and Ireland and that means strengthening winds, could be some
03:21disruption for those winds, we'll keep an eye on that one, and heavy rain arriving for
03:25the second half of Monday and into the start of Tuesday. So that low swiftly follows the
03:31weekend's areas of low pressure and there's another feature there waiting for Tuesday
03:37perhaps ready to be picked up again by that powerful jet stream and sent quickly to the
03:43UK to bring another bout of rain. This is the story so far of the winter 1920 half term
03:50report from any snowmantics, anyone who loves the snow would give it an F minus. The question
03:57is why has the jet stream been so powerful, why has the weather been so unsettled? For
04:02that we have to look quite high in the atmosphere and many miles away to the North Pole. Now
04:09in recent years we've talked occasionally about the stratosphere above the North Pole
04:13because it can influence our winter weather and during the winter there's something that
04:18forms called the stratospheric polar vortex, it's an area of intense cold that forms above
04:22the North Pole and through the winter so far it's been locked in place by unusually strong
04:27winds surrounding the North Pole. You'll notice this flows in tandem with the jet stream,
04:33this is at 80,000 feet or thereabouts but it helps to reinforce the jet stream, add
04:37fuel to it through the winter months and that's what's been happening. Now the beast from
04:42the east when that occurred two years ago was because all of this disrupted and it led
04:46to cold air spilling out and heading to the UK. No signs of that happening in the near
04:52future, that strong robust stratospheric polar vortex will keep the cold air above
04:57the North Pole and away from British shores. It also has been enhanced, that stratospheric
05:04polar vortex, it's had a helping hand from elsewhere in the atmosphere as far away as
05:07the equator and the winds blowing again in the stratosphere above the equator have been
05:12in a phase that tends to help the stratospheric polar vortex stay in place and tropical rainfall
05:19patterns have also helped to enhance it. If you want to do any further reading on these,
05:24the Quasi-Biennial Oscillation and the Madden-Julian Oscillation, Google those and there are some
05:29pages on that through the Met Office website. Essentially what I'm saying is the first half
05:34of winter everything has been in favour through the weather patterns around the world of this
05:39strong jet stream and low pressure systems bringing wind, rain and mild air and there
05:45are very little signs of change at least at first next week. We keep the strong jet
05:50stream, we keep more areas of low pressure coming through. But one thing that will likely
05:56start to change towards the end of next week is this area of high pressure over the continent.
06:02Let's fast forward to the end of next week and you'll see it build to the east of the
06:05UK but we keep low pressure close to the south of the UK and so I expect what will happen
06:10is we'll keep southerly airflow, we'll keep mild air and we'll keep more wind and rain
06:15coming in especially for western and southern Britain. But with that high pressure building
06:19it's not far away so some hints that the weather may begin to improve later on in the period
06:27but for next week it's more wind and rain, very mild as well. Just those small signs
06:33of an improvement later and the wind patterns and the rainfall patterns around the equator
06:38and the tropics could also start to help things improve later in January but that's a long
06:42way off. Next week for the time being looks very unsettled. Bye bye.