Storm Arwen will affect the UK on Friday and Saturday. It is the first named storm of the 2021/22 season and was named by the UK Met Office on Thursday 25th November. As this low pressure sinks southwards over the North Sea it will bring Arctic air and wild conditions later on Friday.
All of the UK will feel much colder by Saturday in the brisk north winds. At times, it will be stormy, wet and even wintry. There are warnings across much of the UK and these relate to wind strength and the possible impacts. And there is one for snow.
“High winds associated with Storm Arwen are expected to cause some travel disruption and damage.” MO
There is an amber warning for this wind storm over NE Britain from Orkney down to Yorkshire. There is also a wider area under two yellow wind warnings, one for Friday and another continuing into Saturday. It is only SE England which is not under any warning.
The colour difference balances how likely the event is and if the impacts could be low, moderate or high.
Matrix showing Friday's Amber warning and the wider yellow
Storms are named to help communicate severe weather warnings and forecasts. It gives a weather event a label, for easy access and sharing on social media and should help draw attention to what is coming up.
The centre of this low pressure approaches Shetland tonight. Strong west to NW winds arrive for the Western Isles and NW Highlands before midnight with heavy rain from the warm front and some mountain snow. The fronts all push southwards reaching the English Channel by midday on Friday. There will be blustery conditions with gusts over 50mph and a sharp veer in the winds as the cold front passes by. By lunchtime, the UK will be in a colder but brighter slow with plenty of showers. These will be of snow for the far north of Scotland. Also wintry for west coast Scotland, Northern Ireland and northern England with snow for Snowdonia.
Already the winds will be strengthening for the far north of Scotland and signs of gusts around 60 to 70mph. Shetland, west coast Scotland down through the North Channel, all very windy before 3pm.
The main focus for disruption, the amber area runs from Friday 3pm until Saturday 9am. This covers the main Friday evening rush time, with the extra busyness of the end of the week/ start of the weekend travel. Gusts of over 70mph are forecast
By Friday teatime and evening, gales will be affecting NE Scotland in the top left quadrant of winds around the low centre. A96 and A90 looking prone. Severe gales possible Aberdeen to Orkney for exposed areas. Also wild conditions for west coast Scotland, the island ferries and crossings to Northern Ireland.
The high winds from NE Scotland will affect Lothian and Edinburgh into the evening, transferring along the A1 into the Scottish Borders
The strong north winds will also affect north and western Wales trough Friday evening. Gales for Anglesey, A55 and the Welsh mountains with the strong winds reaching down over SW Britain during Friday night
By Saturday morning most of the UK will be in a cold, moderate to fresh north wind and boy will you know about it, when you step outside. Especially from The Forth down to The Wash.
“Storm Arwen brings with it the risk of disruption to travel, power cuts and potential damage, especially within the amber area and near the coasts, where large waves could see material thrown onto coastal roads, sea fronts and properties. “ MO
As the ‘north wind doth blow, we shall have snow’. There is also a warning for snow for inland parts of the Highlands, Grampian, A9, and into central Scotland (NW Angus and northern Perth & Kinross). This runs during Friday pm with warnings of blizzard conditions, drifting and so travel disruption. The wintry showers will turn to more persistent hill snow, mostly above 200m with accumulations forecast
“Spells of hill and mountain snow combined with high winds will give blizzard conditions and cause travel disruption.”
Snow is also likely over the higher Pennine routes during Friday night from the Cheviots through the north Pennines across to the M6 in Cumbria, maybe reaching the Yorkshire Dales and still along the higher parts of the A1 in Yorkshire early on Saturday
As Saturday progresses there will be more icy rain showers with sleet and a bit of hill snow, for exposed coasts of northern Scotland, down the North Sea coasts and still the Pembrokeshire Dangler set up. SE England and East Anglia will keep the brisk cold north winds for the longest on Saturday as more settled weather heads in from the west. Wintry showers will persist in the northerly flow for eastern Britain on Sunday.
Although the main snow accumulations are expected over the Scottish mountains and then hills exposed to the northerly flow, in this cold air other areas might wake to a temporary covering of white on Saturday morning. Prepare for the cold wind and if you are travelling later on Friday do stay up-to-date with the Storm Arwen forecast.