Tornadoes

[tugmistress]

Hi Guys,

I just received this email from one of the people in my local area, i am hoping someone can help me reply as my knowledge goes about as far as 'it's a bloody strong wind going round in a circle'

Any help greatly appreciated

here it is ....

I hope you don't mind a strange request but as you seem to ' do the weather' rather well I hoped you might be able to help.

I know Tornados are rare in Scotland but can you suspend reality and explain to me in words of one syllable or less the weather conditions that would allow a tornado to form a pretty severe one at that. It is for a scenario I am putting together and I wuld like to get the facts right

[stormchaser1]

Hi Tugmistress

Just thought this sight might be of some help to you

http://www.torro.org.uk/TORRO/britwxextrem...ear.php#January

Although you have probably already tryed it

its the main TORRO site

nigel

go to SEVERE WEATHER click on Tornados FAQ , there is a load of answers in there for you

nigel

[BrickFielder]

The most important condition is instability which in simple terms means that air must be rising at a rapid rate. This happens when there is warm air below at our level and colder air above. Where the temperature difference between the surface and above is high enough and the difference fairly linear with rising height then you have the conditions suitable for a heavy shower or thunderstorm. All you need then is a focus or trigger which tends to be upper level troughs or low level moisture and wind convergence.

The theory of tornadoes is that they can descend down and spin up from a slower bigger vortex within the cloud or spin up from the surface. The first method tends to lead to the damaging tornadoes we hear about in America whilst the other involves different land and sea surfaces and stormss interacting which tends to happen more often in the UK giving shorter lived and less violent tornadoes.

Ideally you require fairly light winds at the surface and strong winds higher up. Winds whould change direction with height spiralling up to create a slower moving vortex (mesocyclone - super cell) within the cloud. Winds that change direction noticeably around the cloud base and below seem more likely to draw the vortex down into a tornado.

Cliffs ,mountains ,storm gusts ,off shore sea breezes, dust devils can all be the cause of low level vortexes which under the right circumstances can be bent upwards into a tornado or spout.

Check out the Estofex education links

Edited February 26, 2007 by BrickFielder