0:00:03 > 0:00:05I'll get onto the first week of weather in April in just a moment.
0:00:05 > 0:00:07First of all, a quick look back at March,
0:00:07 > 0:00:10because the provisional statistics are in.
0:00:10 > 0:00:12Overall, it was a pretty average month.
0:00:12 > 0:00:14Average sunshine, average rainfall and average temperatures.
0:00:14 > 0:00:16But there were, as this map shows,
0:00:16 > 0:00:19some significant regional variations.
0:00:19 > 0:00:21This map showing the minimum temperatures
0:00:21 > 0:00:23and, actually, the nights were pretty cold,
0:00:23 > 0:00:26below average across the southern half of the UK,
0:00:26 > 0:00:29whereas parts of northern Scotland were above average.
0:00:29 > 0:00:32Now, most starting Thursday on a pretty chilly note.
0:00:32 > 0:00:34A frost across parts of the UK.
0:00:34 > 0:00:36And, again, it's a day of sunshine and showers.
0:00:36 > 0:00:38The showers initially focused across south-east Scotland,
0:00:38 > 0:00:41north-east England, hail and thunder is possible,
0:00:41 > 0:00:44and becoming more widespread as the day goes on.
0:00:44 > 0:00:45But they'll be fairly slow-moving.
0:00:45 > 0:00:48Could be quite intense, but there won't be as many of them around
0:00:48 > 0:00:50and parts of Northern Ireland, Wales,
0:00:50 > 0:00:53south-west England, northern Scotland,
0:00:53 > 0:00:54may well simply stay dry and sunny.
0:00:54 > 0:00:57Overnight, again, the temperatures will be dropping sharply.
0:00:57 > 0:01:00A colder night across the south on Thursday night and into Friday.
0:01:00 > 0:01:02But not as cold in Northern Ireland,
0:01:02 > 0:01:04because here we'll start to see a change.
0:01:04 > 0:01:06A weather front arrives, the breeze picks up,
0:01:06 > 0:01:08the cloud arrives, and then it turns wet.
0:01:08 > 0:01:11A wet day for Northern Ireland and western Scotland.
0:01:11 > 0:01:13The rain creeping into other parts of Scotland,
0:01:13 > 0:01:14maybe north-west England, too.
0:01:14 > 0:01:17For the bulk of England and Wales, Friday's a fine day.
0:01:17 > 0:01:20Where the sun hangs on for longest, we could reach 14 Celsius.
0:01:20 > 0:01:22The weather front looks like winning
0:01:22 > 0:01:24and pushing rain across all parts into the weekend.
0:01:24 > 0:01:26But hold on. It stops through Saturday
0:01:26 > 0:01:29and start to pivot back as low pressure approaches,
0:01:29 > 0:01:31anchoring itself to the west of the UK.
0:01:31 > 0:01:33When those weather fronts do that,
0:01:33 > 0:01:35there's always some uncertainty about the position.
0:01:35 > 0:01:37It could be a bit further south or a bit further north.
0:01:37 > 0:01:40But there'll be some rain across northern Britain on Saturday,
0:01:40 > 0:01:42whereas many southern areas look dry
0:01:42 > 0:01:45and, again, with some sunshine, reasonably warm.
0:01:45 > 0:01:47It's turning warmer because the low anchored to the west
0:01:47 > 0:01:49is allowing the winds to come up from the south-east,
0:01:49 > 0:01:52drawing up some warm air from France.
0:01:52 > 0:01:54When that happens, as well as turning warmer,
0:01:54 > 0:01:58it also, potentially, brings the risk of heavy thundery showers.
0:01:58 > 0:02:00A lot of uncertainty about the intensity
0:02:00 > 0:02:01and where we see these downpours.
0:02:01 > 0:02:04They could be tracking northwards during Saturday night
0:02:04 > 0:02:05and into Sunday.
0:02:05 > 0:02:07As they clear, again, with the warmer air,
0:02:07 > 0:02:09temperatures, if we see some sunshine,
0:02:09 > 0:02:12could easily get to 16 degrees or more.
0:02:12 > 0:02:15Then into next week. Quite a bit of uncertainty, it has to be said.
0:02:15 > 0:02:16All tied into the jet stream.
0:02:16 > 0:02:19We've been watching John Hammond the last couple of days,
0:02:19 > 0:02:21he's been talking about this change in position,
0:02:21 > 0:02:25turning more straightforward, as you might imagine, from east to west.
0:02:25 > 0:02:28But notice the jet stream's never that close to the UK
0:02:28 > 0:02:30and it looks like it'll be relatively weak.
0:02:30 > 0:02:33That's what happens at this time of year.
0:02:33 > 0:02:35The jet stream is strongest through winter, and that's because
0:02:35 > 0:02:38that's when you have the strongest temperature contrast.
0:02:38 > 0:02:41In the winter months, the Arctic is bitterly cold.
0:02:41 > 0:02:42It doesn't get any sunshine.
0:02:42 > 0:02:44And there's a strong contrast
0:02:44 > 0:02:47between the very cold air and the mild air.
0:02:47 > 0:02:51It's that strong contrast that produces a strong jet stream.
0:02:51 > 0:02:54Now, this time of year, into the spring months,
0:02:54 > 0:02:57the Arctic is starting to warm up, we're beyond the equinox,
0:02:57 > 0:03:00and so that contrast isn't as marked,
0:03:00 > 0:03:03the jet stream isn't as strong.
0:03:03 > 0:03:07That's why we tend to get more storms in the autumn and the winter.
0:03:07 > 0:03:09Not saying there won't be any stormy weather
0:03:09 > 0:03:11over the spring or summer months,
0:03:11 > 0:03:14but that's one reason why the jet stream is a little lighter,
0:03:14 > 0:03:16a little less intense.
0:03:16 > 0:03:18It will, though, be influencing things next week.
0:03:18 > 0:03:19The westerly winds will return.
0:03:19 > 0:03:22After some brief warmth, the days will turn cooler.
0:03:22 > 0:03:23There'll be some showers around.
0:03:23 > 0:03:25The nights, though, should be a little milder.
0:03:25 > 0:03:28Don't forget, we're talking about patterns here.
0:03:28 > 0:03:30We'll firm up on the details next week.