On 22 November 1981, a
rapidly deepening low-pressure
extratropical cyclone was centred just off the northern coast of Scotland. The central pressure of this system was 994 mbar at 12:00 GMT on 22 November, deepening to 968 mbar by 12:00 GMT on 23 November. At the same time, a high-pressure
anticyclone was pushing into southern England from mainland Europe. There was an unusually strong upper-level temperature gradient between the low- and high-pressure systems, with the low-pressure system funnelling in cold, arctic air from the north, clashing with humid, subtropical air moving up from southern Europe in the anticyclone. During the morning of 23 November, a
cold front attached to the southern edge of the low-pressure area began to cross the United Kingdom from west to east. Fuelled by this temperature gradient and warm subtropical air to the south, a number of
supercell thunderstorms became embedded within the southern edge of the cold front and its pre-frontal rain bands, spawning the first tornadoes over Wales around 10:30
GMT. By mid-afternoon, 104 tornadoes had been confirmed across the United Kingdom. Several days after the tornado outbreak, the high-pressure anticyclone to the south of the British Isles broke down, allowing colder arctic air to move in from the north, resulting in the start of a
record-breaking cold wave. == Confirmed tornadoes ==