10 Day Trend 04/09/2024 – Summer for some, soggy for others – Met Office weather forecast UK

hello and welcome to the Met Office 10day Trend meteorological Autumn may have begun but if you live in Western Scotland Northern Ireland or Northwest England you may be forgiven for thinking you've entirely missed meteorological summer and that's because summer 20124 in the northwest of the UK was considerably wetter than average the blue colors on this map show how rainfall was above the 100% of the average for summer across Western Scotland nor West England and parts of Northern Ireland and in some spots across Northwest Scotland we saw one and a half times 150% of typical summer rainfall it was also considerably cooler than average in the same locations and in fact although this map shows how the average maximum temperature through summer compared with the 30-year average if you look at the day today maximum temperatures some parts of Western Scotland kinu akaga didn't see a temperature reach 24 C throughout June July and August that compares with May when those same locations saw temperatures above 25° better late than ever you might say this Friday could see temperatures higher across parts of Western Scotland and even parts of Northern Ireland compared with the entire summer season highest temperatures perhaps since May or a smaller chance the highest temperatures in some spots of the year so far here's what's happening the jet stream at the moment is extending South across the UK a very elongated setup and when it elongates this much it can cut off from the main flow into a entirely separate circulation this is known as a cut off low and you get an upper low and a surface low just cut off from the main flow of the jet stream so just Meandering erratically around separate from the main flow and therefore getting stuck somewhere now earlier in the week if you watched the week head forecast there was some uncertainty about where this cut off low would end up whether it would be to the east of the UK or to the South with very big differences across the UK as a result it looks very likely now that it's going to be cut off and it's going to stick to the south of the UK through Thursday Friday Saturday Sunday and even into Monday that means some very heavy rainfall just to the north of that pushing into Southern parts of the UK for several days in a row that's of key concern in the next few days and those Spells Of Rain are going to add up and they're going to cause some impacts so this is the rainfall on Thursday afternoon heavy persistent and some thundery outbreaks of rain moving up from the near continent and affecting South Wales parts of West country Southwest England South Coast and this is 4 p.m. on Thursday today but really fast forwarding after that it continues to be wet across the same locations the rain ebbing and flowing but essentially further spiraling bands of rain pushing North across Southern counties of England easing off for a time for South Wales but really south of the M4 Corridor that's where the wetest weather is expected to be through Thursday and into the start of Friday then by Friday afternoon another spell of rain moves North across these same areas I wouldn't take the location of these rain fans too literally it all depends on the instability over northern France for example and how thundery outbreaks of rain develop there and those can have uh those can be very uncertain in the computer modeling and therefore it's a little uncertain at the moment in terms of exactly where we'll see the heaviest rain but this is the total rainfall through Thursday and Friday the key over here on the right and just indicates widely 50 60 mm across Devon Cornwall Somerset into Dorset parts of Hampshire for example and in some places more than 100 millim through that period in fact one or two spots could see 100 millim or so in the space of 24 hours on Thursday and then a few other spots not necessarily the same locations could see again 100 millimet or so on Friday and that amount of rainfall across Southern parts of the UK could cause some impacts localized flooding River flooding and transport disruptions so Yellow Rain warning in force for Thursday and Friday stay up to date with the latest updates on that through the metal office website and app also some rainfall starting to accumulate later Friday further north of the M4 Corridor as these bands of rain start to move north once again but initially the main cause for concern is South Wales into the south of England especially the West country and the Southwest why is the rain going to be so heavy it's because of instability in the atmosphere because of the cut off up a low and the surface low of France and also a lot of humidity present in the atmosphere now this is the the time of recording Wednesday relatively cool air across the UK but as that low pressure forms over France we're going to see this circulation drag very warm and humid air from Central Europe over the North Sea and into the UK so those colors turning more orange as the days progress over the next few days easterly winds yes but not coldy easterly Wind by any stretch of the imagination this is humid air returning to the UK and that's not only will lead to those heavy outbreaks of rain across Southern parts of the country but it also lead to extensive cloud cover thick layers of cloud in the South where we've got that heavy rain as well as some Hill fog and Coastal fog in the South but not only that across Eastern parts of the UK especially Northeast England into Eastern Scotland we're going to see fret and ha a lot of low Cloud just persisting along that east coast and perhaps a few miles in land as well low Cloud mist and MC persisting through Thursday and Friday a STK contrast compared with Western Scotland and Northern Ireland Northwest England where the cloud will be well broken up by Friday and lengthy Spells Of Sunshine will develop and that is reflected in the temperatures so not only have we got the humidity and the Sunshine on Friday we've also got the Fone effect where the air dries up over the hills to the East and then as it descends again drier air it's warmer and allows temperatures to reach into the mid 20s if we see 25 degrees or so in some of those locations I mentioned earlier then it would indeed be the warmest day since May so 2 24 25° 23 there for Northern Ireland but High Teens where we've got the mist and low Cloud along the east coast it's not just the Northwest we'll see the warmest air it's also likely to be relatively warm through parts of North Wales into the Midlands East Anglia for example 25 to 27 celsus on Friday so for some on Friday a return to Summer like warmth but for others some very wet weather indeed in the South and you can see that contrast on Friday in the temperature compared with average map here this is compared with the September maximum temperature average considerably above average through Central and Northwestern parts of the UK closer to average in the Northeast and more especially the South now it's worth bearing in mind that there's essentially a knife edge gradient there between the clear skies humid and very warm weather if the sun comes through temperatures in the 25 26 27 range across central parts and the very wet weather across Southern areas and with that added uncertainty about the exact position of the bands of rain in the South I would bear that in mind because if you're in some of these areas say across South Wales through Bristol just around north of the M4 where there's that boundary nearby then whether you're on the very warm and sunny side or whether you're on the very wet side will make a huge difference and the margins are very fine indeed so your weather app might oscillate every few hours depending on whether it's putting the rain band in one position or the other and it will only be matter of Miles whether you're in that wet weather or in the very warm weather so that's something to bear in mind if you live in that boundary Zone where it's uh well wet on one side and very warm on the other side likewise temperatures overnight are likely to be considerably above average especially across Northern parts of the UK so some very warm nights coming up heading into the weekend and we keep a lot of that cloud cover once again on Saturday morning across Northeastern and Eastern parts of the the country I think the rain easing off for a time on Saturday perhaps a drier interlude in the South but further wet weather is likely to come along later so temperatures recovering for a Time likely to stay very cloudy and drizzly across Southern counties of England especially the Southwest perhaps South Wales whilst again Western Scotland Northern Ireland seeing the best of the warm sunny spells into Sunday another band of rain moves North this time it moves a little further north into Central parts of the country again heavy outbreak of rain but a little bit of uncertainty about exactly where this rain band will end up drier Northern England Scotland Northern Ireland still some mist and drizzle around the Northeast Coast less warm I'd say by Sunday across Western Scotland and Northern Ireland the winds are starting to change direction starting to pull a bit more cloud in but staying largely dry now I mentioned the uncertainty about the distribution of the rain again through the weekend and it's even more uncertain unfortunately across Central and Southern Parts where we'll see the heaviest outbreaks of rain through the weekend and the largest rainfall accumulation some areas again seeing 50 to 75 millimeters of rain through the weekend but and different weather models have slightly different locations for that rain so the American model there has it more across Southern parts of the UK the European model has it further north into parts of mid Wales the Midlands for example East Anga whilst The Metalist model has it somewhere in between so that's something we'll keep a close is and hopefully we'll be able to update you a bit more in the next couple of days either way the trend through Sunday and into Monday is for the wetter weather to start to move towards the southeast could be further Heavy downpours Across East Anglia in the Southeast into Monday as that low moves away but by this stage there's a big change in the bigger picture with low pressure to the East and higher pressure to the West we're going to start to see Northerly winds and this by Tuesday to Thursday 12 of September is the most likely weather pattern coming out of all the different computer models and relatively high confidence about this low pressure to the east higher pressure to the west and much cooler Northerly winds these are the temperature anomalies -4 minus three that sort of thing and with that Northerly wind we're likely to see quite a number of showers coming into Northern and Eastern Scotland in particular Northeast England for example drier towards the west and the South but feeling considerably cooler everywhere particularly following the relatively humid air that we'll see over the next few days but at least it will be drier in the South even if it's wetter towards the Northeast then a bit of uncertainty heading into the following weekend as is naturally the case 10 11 days ahead but it looks fairly likely that we'll see a return to Atlantic weather dominating with low pressure arriving and that bringing Spells Of Rain into the Northwest and wind switching to more of a southwesterly rather than a northeasterly that shows up quite well in this charts now this takes a bit of explaining but this essentially tells us whether norly or souly are most likely each day through the next two weeks Northerly are colored in blue souly are colored in red this takes many different computer model runs from uh 00 different models and it shows on the top row there the most recent output from all those different models for each day whether the Blues are showing up strongly that means Northerly are very likely that's the middle of next week for example and then this switch to southernly from mid September and the previous model runs are all listed below so you can see there's that consistency from Blues middle of next week to Reds middle of September this next chart shows a similar thing but instead of Norther and southernly it's Wester e or Easter and the Wester are colored in blue this time so some Wester around my alarm going off beg pardon some Wester days around around the uh or or Easter days for example some weak Easter days around the middle of the week next week and then back to westes so southwester essentially the main theme from the middle of September and just to finish up with the temperature trend for two relatively different locations across the UK Southampton and Glasgow Glasgow shows this especially well this increase in temperatures the red boxes there going above the average line through the weekend and as that warm air comes in from the East then this sudden drop around the middle of next week to below average before a recovery towards average around the middle of September as those uh Southwest ofies return and as low pressure returns from the Atlantic Southampton similar Trend but it's not going to be quite as warm temperatures won't be quite as far above average through this weekend because of those spells of rain and the increase in Cloud so big swings in the weather over the next 10 days but of course for day-to-day updates we'll keep you updated right here on YouTube bye-bye