This week, the UK is set to turn a little milder before potentially seeing heavy rain across the south at the weekend.
In this deep dive, we’ll explore what’s happening high above the North Pole, what it means for our weather, and take a look at some fascinating global and local phenomena – including the Pembrokeshire Dangler and a tropical system bringing extreme rainfall to Sri Lanka.
What’s the outlook for the UK’s weather?
In the short term, the UK is experiencing a northerly airflow, bringing sunshine and showers today. Clear skies tonight will lead to a widespread frost, with temperatures close to freezing by Wednesday morning. However, a significant change is on the way.
By Thursday, Atlantic systems will push in, bringing much milder air. Temperatures could rise by 9°C or more compared to 24 hours earlier, with double figures likely in many places. Alongside the warmth, wet and windy weather will return, particularly in the northwest where strong winds are expected Thursday night into Friday.
Weekend outlook
The weekend could bring some interesting developments. A low-pressure system is forecast to approach the southwest of the UK on Saturday. The Met Office model currently shows a deep low, but this may be overdone. Other models, such as ECMWF, suggest a weaker low further south, possibly over northern France.
A rather unsettled rest of the week, with showers and longer spells of rain at times 🌧️
— Met Office (@metoffice) November 26, 2025
Quite windy too, especially in the north 🍃 pic.twitter.com/qHTiRjdBXy
Ensemble forecasts show a wide spread of possibilities, from a weak low in the Bay of Biscay to a more intense system crossing England and Wales. The most likely scenario is a low-pressure system bringing heavy rain to southern parts of the UK, with a small chance of strong winds. Given the recent wet weather, any additional rainfall could cause localised flooding, so this is one to watch.
Global focus: Extreme rainfall in Sri Lanka
While the UK deals with mild and wet conditions, Sri Lanka is facing a very different challenge. A tropical depression combined with the northeast monsoon is set to deliver exceptional rainfall. Moist air from the Bay of Bengal is clashing with south-westerly winds, creating persistent heavy rain.
This is the wettest time of year for Sri Lanka, with an average of 250–300 mm of rain in November. However, current forecasts suggest totals could reach 800 mm, with some spots potentially seeing 1,000 mm – that’s a metre of rain in just a few days. Such amounts could lead to significant flooding, including one-in-20-year river flood events across the island. The situation will be monitored closely as the system remains slow-moving and continues to feed moisture inland.
READ MORE: “Seven inches of snow”? “Freakish warmth?”: Met Office weather headline review
The Pembrokeshire Dangler returns
Back closer to home, another fascinating feature has appeared – the Pembrokeshire Dangler. This convergence line forms when cold northerly winds travel over the relatively warm Irish Sea, picking up heat and moisture. As these winds clash with airflows affected by friction over land, they are forced upward, generating showers or even snow.
Last Thursday, the Pembrokeshire Dangler produced heavy snowfall, with reports of 20–30 cm in places. Today, it is back, though bringing rain rather than snow due to milder conditions. High-resolution satellite imagery shows the streamer clearly, with lines of showers feeding down through the Irish Sea towards Pembrokeshire and Cornwall.
This phenomenon is most common in late autumn and early winter when sea temperatures remain relatively warm compared to cold air aloft. It’s a striking example of how localised features can create significant impacts.
There is also evidence of another phenomenon taking place way above our heads, known as sudden stratospheric warming, but what is it, and will it impact our weather?
What is sudden stratospheric warming?
High above the North Pole, around 20 to 25 kilometres up in the stratosphere, temperatures have rocketed in recent days. This phenomenon is known as sudden stratospheric warming (SSW). Data from the Japanese Meteorological Agency shows that temperatures at 30 hectopascals have surged well above the seasonal average.
Normally, as we move through autumn into winter, temperatures in the stratosphere dip steadily before rising again in spring and summer. This year, however, the temperature has spiked dramatically and unusually early in the season. While this sounds dramatic, temperature is only part of the story. The winds high in the stratosphere, particularly those associated with the polar vortex, play a crucial role.
READ MORE: What does a “blend” of AI and physics mean for weather and climate modelling?
The polar vortex and why it matters
The polar vortex is a band of strong westerly winds that circles the Arctic high in the stratosphere. It forms every winter and helps maintain the flow of the jet stream lower down in the atmosphere. When the vortex is strong, it keeps the jet stream moving west to east, bringing relatively mild and unsettled weather to the UK from the Atlantic.
This year, the polar vortex has been weaker than normal and has recently weakened further. For a full-blown SSW event, these westerly winds need to reverse and become easterly. At the moment, they are close to zero but have not flipped, and forecasts suggest they may remain weak rather than reversing completely.
Why does this matter? A weakened polar vortex can ripple down through the atmosphere over a couple of weeks, disrupting the jet stream and allowing blocking patterns to form. These blocks can lead to colder spells in the UK. However, this does not always happen, and the current event looks minor rather than major.
How unusual is this event?
This SSW is occurring very early in the season. The earliest on record was in late November in the late 1960s, so this could be close to record-breaking. However, because the winds are unlikely to reverse, this is considered a minor event. At the surface, the immediate impact is limited. Current model runs suggest that the chances of blocking patterns and prolonged cold weather have decreased compared to a few days ago.
The current sudden stratospheric warming is expected to have relatively little impact on UK weather. While SSW events often lead to colder conditions in Europe, this particular SSW is unlikely to disturb the stratosphere for sufficiently long to significantly influence UK weather patterns.
Keep up to date with weather warnings, and you can find the latest forecast on our website, on YouTube, by following us on X and Facebook, as well as on our mobile app which is available for iPhone from the App store and for Android from the Google Play store.
