Friday, May 23, 2014
Numerous Hunts Post readers have sent in pictures of a tornados that hit Huntingdonshire yesterday (Thursday).
Sunshine heats the ground causing convection and an upward movement of air referred to as a thermal. As the ground temperature increases, moist air rises and meets cold, dry air above it.
The warm air rises forming low level shallow cumulus clouds which become trapped under the layer of warm, dry air and eventually form into the heavier and denser cumulonimbus clouds.
As the strong wind currents move through the cloud from opposite directions, they cause rapid changes in speed and direction, referred to as wind shear. As the winds travel higher, they begin to rotate and as the spiral tightens, the winds become increasingly violent.
The updraft eventually spirals down to reach land and narrows resulting in a faster rotation. The rotating updraft reaches towards the ground as a funnel cloud but only becomes classified as a tornado when it reaches ground.
This is the mature stage and can be when the most damage occurs during the tornado due to the funnel cloud being at its widest and of a near-vertical angle.
At the end of the life cycle of a tornado, the tornado begins to shrink and the funnel becomes tilted and eventually diminishes, conditions are still dangerous throughout this stage. The tornado then enters the decay stage in which it weakens in width resulting in an eventual break up.
The first was seen at about 2.30pm by workers at Elstree Light and Power, based at Alconbury Weald, that was in the Brampton area and was followed quickly by a second towards Sawtry.
Experts at the Met Office class a tornado as a funnel cloud that touches the ground.
Catherine Parkinson tweeted The Hunts Post with a picture of a funnel cloud near the Brampton Interchange.
Craig Timbrell, of Stukeley Meadows, also captured a tornado at Alconbury Weald, with Katrina Lilly, Josh Mayes and Martin Amos snapping the weather phenomenon.
• Did you see the tornado? Email email@example.com with sightings, pictures and videos.