Week ahead - Tropical weather system adds some uncertainty this week
Some places could have a soggy few days this week as we get some tropical air heading to the UK. There’s some uncertainty about the details because of how the warm humid air interacts with the jet stream. Alex Deakin explains
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00:00Let's take a closer look at the weather for this week, because it could be quite interesting.
00:04There will be some fine and sunny days around, but for some parts of the UK it could get
00:10really quite soggy through Tuesday, Wednesday and Thursday. But there is a fair bit of uncertainty,
00:16particularly around Wednesday and Thursday, thanks to a tropical weather system. All will
00:21be revealed. After that, though, it does look as if the weather should calm down again with
00:26drier and brighter weather for most parts of the UK as we go towards the weekend. But let's take a
00:32look at the bigger picture. It was this area of low pressure that brought the windy weather on
00:36Sunday. That's cleared away and now we're looking at this little area of low pressure coming in for
00:41Tuesday, making for something of a soggy sandwich with quite a bit of wet weather over these central
00:46areas, especially North Wales and North West England. But either side of it, something a
00:49little drier and brighter. So that's Tuesday's weather system that scoots away and then something
00:55pretty similar looks like following through Wednesday and Thursday. But it's this one that
01:01there's a bit of uncertainty about. For the reasons behind that, we need to again take a look at the
01:06bigger picture and the here and now. This is the satellite image showing Sunday's low pressure
01:11system. This area of cloud will bring the rain on Tuesday. And it's this area of cloud which is
01:17actually a tropical storm, Tropical Storm Eduard. Now, it's interesting that we're up to the letter
01:23E. The earliest we've been in the season up to the letter E. But it's not a particularly interesting
01:28storm in itself. It's not particularly strong and it's not really near any land. And during Monday, it
01:34will stop being a tropical storm. It will transition into just a more ordinary area of low pressure,
01:41which means we can start drawing weather fronts on it. And it is going to drift its way further
01:46northward. So no longer a tropical storm. But notice it does still have some warm and humid tropical
01:52air mixed in with it. Now, that can add to the uncertainty in the forecast because it's basically a bit
01:58more energy. And sometimes the computer models can't handle this particularly well. And the extra bit of
02:04uncertainty then comes from how it will interact with the jet stream, that fast moving ribbon of air high
02:10up in the atmosphere. Now, the most likely scenario is that this area of low pressure will just stay on
02:17the warm side of the jet just to the south of it as it approaches the UK. However, it wouldn't take much for the
02:23jets to be a little further south or the low to be a little further north. And if this low crossed the jet
02:29stream, well, then it could really pick it up, really intensify that low and turn it into something a bit
02:35lively. It could then bring a spell of really quite heavy rain and some strong and gusty winds. Now, that's
02:41just a small chance at the moment, but it is an area that we need to keep a close eye on. The most likely
02:47scenario is that this low will just drift in, bring its warm and humid air with it and bring quite a bit of moisture
02:53and so more rain for parts of Wales and southern England in particular. But as I said, it does need watching. Once
03:00that's out of the way, it looks like high pressure will move in towards Friday and Saturday, bringing drier and
03:05sunnier weather for all of us as we go towards the weekend. But there is that bit of uncertainty just about how that
03:11weather system plays out over the next few days. So make sure you stay up to date with the very latest from the Met
03:16office by following us on social media.