0:00:03 > 0:00:04I know a lot of you like it
0:00:04 > 0:00:06when we talk about the jet stream in this broadcast.
0:00:06 > 0:00:08You might reconsider by the end of this.
0:00:08 > 0:00:09There's a lot of jet stream coming up,
0:00:09 > 0:00:10but hopefully it's worth it.
0:00:10 > 0:00:12I want to show you a picture
0:00:12 > 0:00:13from glorious sunshine
0:00:13 > 0:00:14across much of Wales and England
0:00:14 > 0:00:17during Wednesday, 18.8 Celsius in the sun
0:00:17 > 0:00:19at London's Kew Gardens,
0:00:19 > 0:00:21the highest temperature the UK's had so far this year.
0:00:21 > 0:00:23That 17 in Hawarden in north-east Wales
0:00:23 > 0:00:25the highest that Wales has seen so far this year
0:00:25 > 0:00:27and you might be surprised to see
0:00:27 > 0:00:29this big dome of mild air across the UK.
0:00:29 > 0:00:31Of course, the highest temperatures are realised
0:00:31 > 0:00:32when we get some sunshine
0:00:32 > 0:00:35and it's high pressure across the UK as well
0:00:35 > 0:00:37that's kept our weather pretty similar
0:00:37 > 0:00:38as we've been through the past few days.
0:00:38 > 0:00:40No great change.
0:00:40 > 0:00:42The jet stream is to the north of us
0:00:42 > 0:00:45at the moment, not severely impacting our weather,
0:00:45 > 0:00:47and if you are new to the jet stream,
0:00:47 > 0:00:48here are a few key facts about it.
0:00:48 > 0:00:53There's a ribbon or a stream of strong winds up to about 200mph
0:00:53 > 0:00:56high in the atmosphere, up to nine miles above us,
0:00:56 > 0:00:58and it's along the jet stream...
0:00:58 > 0:01:01Well, it impacts and influences weather systems and steers them,
0:01:01 > 0:01:04particularly across the Atlantic towards us.
0:01:04 > 0:01:05We haven't been getting anything
0:01:05 > 0:01:07because the jet stream has been to the north of us
0:01:07 > 0:01:08and it's a looping,
0:01:08 > 0:01:11we call this meridional jet stream
0:01:11 > 0:01:12across the Atlantic right now
0:01:12 > 0:01:14and when you see that,
0:01:14 > 0:01:16you know the weather isn't changing very quickly.
0:01:16 > 0:01:17Weather systems, either high pressure
0:01:17 > 0:01:19or low pressure, stick around for some time,
0:01:19 > 0:01:22but fast forward to Friday and, look,
0:01:22 > 0:01:24these weather systems are queuing up
0:01:24 > 0:01:26right across the Atlantic to come into the UK
0:01:26 > 0:01:28on a jet stream which is no longer
0:01:28 > 0:01:29looping up and down,
0:01:29 > 0:01:31but it is taking a more direct
0:01:31 > 0:01:32straight line towards us.
0:01:32 > 0:01:34It is a zonal jet stream -
0:01:34 > 0:01:36it is stronger and on it,
0:01:36 > 0:01:37there are more active weather systems
0:01:37 > 0:01:40and they're coming right for us so, for Friday into the weekend,
0:01:40 > 0:01:43well, things will look and feel very different out there.
0:01:43 > 0:01:44Let's take things day by day.
0:01:44 > 0:01:46We will start with Thursday's weather
0:01:46 > 0:01:47and there is a band of rain
0:01:47 > 0:01:49pushing through Scotland and Northern Ireland,
0:01:49 > 0:01:51heavier for a time before clearing in the afternoon
0:01:51 > 0:01:54as sunny spells and scattered showers follow,
0:01:54 > 0:01:55some of that rain heading into
0:01:55 > 0:01:57northern and western England into Wales,
0:01:57 > 0:01:59the far south-east staying dry until after dark,
0:01:59 > 0:02:01not as much sunshine, not as warm
0:02:01 > 0:02:02and by Friday morning,
0:02:02 > 0:02:04it's quite chilly out there.
0:02:04 > 0:02:06Northern Scotland fares reasonably well
0:02:06 > 0:02:07on Friday, but for the rest of the UK,
0:02:07 > 0:02:09rain pushing south-eastwards,
0:02:09 > 0:02:11but then again, you might want something on your garden
0:02:11 > 0:02:13after it's been, for some of us, quite dry.
0:02:13 > 0:02:16And then this is the picture going into the weekend,
0:02:16 > 0:02:17I showed you it again a second ago.
0:02:17 > 0:02:19You can follow this weather system
0:02:19 > 0:02:22all the way back almost to North America
0:02:22 > 0:02:24and all of that is coming our way.
0:02:24 > 0:02:26It won't be raining all the time.
0:02:26 > 0:02:27I think some of the heaviest rain
0:02:27 > 0:02:29will be focused on western parts of the UK,
0:02:29 > 0:02:31into the hills and maybe Wales, for example,
0:02:31 > 0:02:33will see quite a lot coming down into the hills.
0:02:33 > 0:02:36Another spell of rain sweeping eastwards on Sunday,
0:02:36 > 0:02:37showers following on behind.
0:02:37 > 0:02:40Sunday looks like the windier of the two this weekend
0:02:40 > 0:02:42and it's in the wind, particularly,
0:02:42 > 0:02:43things are feeling cooler.
0:02:43 > 0:02:45Then into the start of next week,
0:02:45 > 0:02:46still low pressure close by
0:02:46 > 0:02:48so it's still looking unsettled.
0:02:48 > 0:02:49Another push of cooler air
0:02:49 > 0:02:51looks like it will come in,
0:02:51 > 0:02:52but as we get to the jet stream,
0:02:52 > 0:02:54look at this.
0:02:54 > 0:02:55It's no longer right across the Atlantic
0:02:55 > 0:02:58towards us, it's doing that looping thing again
0:02:58 > 0:03:01so it looks like the mobility is slowing down
0:03:01 > 0:03:04so pressure systems hang around longer.
0:03:04 > 0:03:05Low pressure at the start of the week,
0:03:05 > 0:03:08but looks like later in the week,
0:03:08 > 0:03:10there'll be a gradual progression to high pressure
0:03:10 > 0:03:12coming back into the UK
0:03:12 > 0:03:14and the influence of that will be
0:03:14 > 0:03:16to settle things down for many of us,
0:03:16 > 0:03:17turn things drier once again.
0:03:17 > 0:03:19It could be pleasant by day,
0:03:19 > 0:03:22but there is a risk of some cold frost overnight.
0:03:22 > 0:03:25So, a weather pattern at the end of next week
0:03:25 > 0:03:27pretty similar to what we have at the moment,
0:03:27 > 0:03:29in between something much more changeable,
0:03:29 > 0:03:31for which, of course,
0:03:31 > 0:03:32we can blame the jet stream.
0:03:34 > 0:03:37The psychiatrist was a figment of his imagination.