A tornado alert has been issued for areas across the South West region overnight and tomorrow (Saturday, December 7). The warning, in place until 4am on Saturday, has been issued by severe weather watchers TORRO (Tornado and Storm Research Organisation).
Severe thunderstorms and winds of up to 75mph could hit part of southern England, according to TORRO, which keeps records of tornadoes, large hail and severe storms across Britain and Ireland, as well as issuing forecasts when there is a risk of severe storms. TORRO says on its website: “Storm Darragh will push a frontal system across the area this evening and overnight. The cold front will tend to split, with the surface portion lagging behind the upper part. This will encourage a shallow moist zone to develop.
“A dry intrusion along should overspread this, especially across the southern half of the indicated area. Hi-res models suggest a broken line of shallow convection developing along the surface cold front, which could evolve into shallow supercells. Instability is very modest, but the shear through the potential depth of such convection could allow rather strong dynamically-augmented updraughts to evolve. Wind gusts to around 70-75mph could accompany the stronger cores, and one or tornadoes are possible too. Please note the larger-scale high winds from the storm are covered by the relevant national met service warnings.”
According its website, TORROR defines a tornado as “a violent rotating column of air that reaches to the ground from a storm cloud in the shape of a condensation funnel created and maintained by strong inflowing winds. The spinning winds can attain extremely high speeds which provide great risk to property and life at the ground and in the air.
“When the humidity is high enough, the tornado funnel is made visible by the circulation of condensed water vapor in its outer sheath, but although the flow of air is inward and upward, the cloud within the low-pressure funnel actually extends downward from the cloud base.”