What a Monday morning. After a long dry and warm spell for much of the UK, heavy rain moved from Northern Ireland on Sunday to soak Britain on September 27th. This was an active cold front, bringing a significant change in air temperature and there was lively line convection along the front.
The line convection, running north-south, brought a short spell of torrential rain to the Monday morning rush hour and, no doubt soaked lots of school children. There were also sudden squally winds and damage in eastern England which suggested that tornadoes had formed.
There have been reports of damage to homes and vehicles near Hull and near to Grimsby. Photos look like there has been an explosion with tiles off roofs, brick walls down. A caravan turned on its side and a motorhome upside down. The heavy rain and gusty winds did lead to poor visibility and tricky conditions on the roads. An HGV lorry fell on its side at the Melton Interchange, Hull as the wild weather moved through, shedding its timber load onto the road and leading to traffic delays.
Humberston near Grimsby and Cleethorpes saw about 20 homes damaged. Cars damaged, roof tiles off and a garden table flung. A roof came off a garage, a greenhouse was broken and cars were damaged in Thorngumbald, near Hull around 10am.
The UK does see tornadoes, usually weak ones (don’t say mini!)
Tornadoes in the UK: "On average, 36.5 tornadoes are reported each year in the United Kingdom. This average is based on the 1981-2010 climatological period, though in reality, the actual yearly figures may vary dramatically from year to year." TORRO
Today we had warm air over eastern England, it was 17C before 9am, and an incoming, very active cold front from the west. Along this frontal band, which was already bringing wet weather, line convection formed. Line convection gives a short spell of intense, torrential rain with sudden gusty or squally winds. That can be memorable enough.
“Sharpening upper trough swings east across the UK Monday morning, with a marked cold front moving east ahead of the trough, bringing a band of heavy rain with embedded wavy squall line or Line Echo Wave Pattern (LEWP)… strong squally wind gusts are possible with passage, with isolated 50-60mph gusts possible. An isolated brief tornado can’t be ruled out either with any broken line segments that develop.” Convective forecast
This intense instability, just ahead of an active cold front, managed to produce severe convective weather today. TORROuk take in reports from the UK and investigate suspected tornado events
“The cold front that has moved east across the UK is a favoured weather setup for isolated, typically short-lived tornadoes and over 60 per cent of tornadoes reported in the UK in Autumn are associated with these setups.” Met Office
During the morning the air temperatures changed. Eastern England had seen 16 or 17C to start the day but behind the front Wales and Northern Ireland started Monday at 11 to 13C and parts of Scotland in single figures. The wind backed significantly from the warm southerly to a cooler fresher westerly. In this unstable airmass, with colder air at mid-levels yet relatively warm Sea Surface Temperatures and bright sunshine heating the land, heavy showers developed with thunderstorms. They were well scattered in the afternoon but still lining up. One line fed up over Belfast, another over the Isle of Man with some spectacular views of Cumulonimbus clouds and their icy anvils up high in the sky. Quite a day.
Top image @steverico whose wife said the noise of the wind and rain was the loudest she had ever heard. Thorngumbald, near Hull
Netweather community forum - Yorkshire and eastern England thread