Storm Bram swept across the UK and Ireland in early December, bringing a potent mix of heavy rainfall, powerful winds, and unseasonably warm temperatures.
This article examines the key weather statistics and meteorological features of Bram, drawing on provisional rainfall and wind data, and placing the event in context with recent weather patterns and historical records.
Rainfall: Intense downpours and regional contrasts
The passage of Storm Bram was marked by intense rainfall, particularly across Ireland, western UK, Wales, and the southwest. Radar and ground observations show that after a showery Monday afternoon, the main area of rain associated with Bram moved into the south on Monday evening, continuing into Tuesday morning.
Some of the wettest spots included Dartmoor and South Wales. On 8 December, White Barrow in Devon recorded over 104.7mm of rain, while Princetown Prison saw 86.2mm. Holne, Priddons Farm, and Dartmoor Training Centre also exceeded 77 mm. In South Wales, Abergorlech registered 62mm, and Treherbert 61.6mm.
You can explore rainfall data for December 8 using our interactive graph below.
These figures are significant, with some sites receiving 20–30% of their average December rainfall in a single night. In southeast Wales and central southern England, the proportion was even higher, up to 40% of the monthly average fell in just a few hours.
Rainfall on 9 December was more moderate in Scotland and northern England. Tyndrum in Perthshire recorded 45.6mm, Tulloch Bridge in Inverness-shire 37.4mm, and Kinlochewe in Ross & Cromarty 35mm. Cumbria’s Shap saw 28.8mm, while Nantyglo in Gwent, Wales, received 27mm.
You can explore rainfall data for December 9 using our interactive graph below.
Why some areas were hit harder
The regions worst affected by flooding and disruption were those already saturated from previous months of exceptional rainfall. South Wales and Southwest England, for example, had erased their rainfall deficit built up over a dry spring and summer since mid-October.
In contrast, eastern parts of the UK, such as East Anglia, still have a significant rainfall deficit despite recent wet weather. This explains why rain warnings and hosepipe bans can coexist in the UK: warnings were issued for the saturated southwest and Wales, while bans remained in place in the drier east.
Winds: Powerful gusts and mean speeds
As the heavy rain moved away, Storm Bram’s focus shifted to wind. Gust speed data shows Capel Curig in Gwynedd recorded a maximum gust of 73 knots, Aberdaron 71 knots, Mona (Isle of Anglesey) and Killowen (Down) 66 knots, and Aberporth (Dyfed) 66 knots. These values highlight the risk of flying debris, dangerous coastal conditions, and transport disruption.
Hourly mean wind speeds were also significant: Aberdaron reached 52 knots, South Uist Range 49 knots, Capel Curig 48 knots, Ronaldsway (Isle of Man) 47 knots, and St Mary’s Airport (Isles of Scilly) 45 knots. Blustery conditions persisted in Scotland, northern England, and Northern Ireland, while the south and southeast saw clearer skies and lighter winds.
Unseasonable warmth: Near-record temperatures
One of Storm Bram’s most striking features was the unusually warm air it brought. Edinburgh Gogarbank hit 16.6°C, surpassing previous December records for the city, and Carlisle set a new UK date record for 9 December with 16.8°C. Magilligan in Northern Ireland reached 16.3°C, just shy of the December record of 16.7°C.
This warmth contributed to the heavy rainfall, as warmer air can hold more moisture.
The meteorology of Storm Bram: A Shapiro–Keyser low
Storm Bram was classified as a Shapiro–Keyser low, a type of rapidly developing low-pressure system with a unique structure. Unlike typical lows, where the cold front eventually merges with the warm front, a Shapiro–Keyser low features separated fronts and a warm core. This structure leads to more rising air, tighter pressure gradients, and stronger winds, explaining Bram’s explosive deepening and severe impacts.
Storm naming: Why Bram follows Benjamin and Claudia
Storm Bram was named by Met Eireann due to its potential impacts on the UK and Ireland. Previous storms, Benjamin and Claudia, were named by meteorological services in Spain and France, which are not part of the Met Office’s Western Europe storm naming group. As a result, Bram was the next official name on the UK and Ireland
Storm Bram stands out as a dramatic December weather event, combining intense rainfall, powerful winds, and unseasonable warmth. Its impacts were shaped by saturated ground conditions, the unique meteorology of a Shapiro–Keyser low, and the interplay of regional weather patterns
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