posted on Sep, 2 2013 @ 06:16 PM
reply to post by PtolemyII
Tornadoes form when you have windshear, and hot air meets cold air. Mixing hot and cold air by themselves won't do it.
In 1999 Aichi Prefecture was hit by 4.
In 2006 Miyazaki Prefecture was hit by one.
Later in 2006 Hokkaido was hit by one.
In 2012 Ibaraki Prefecture was hit by one.
There are at least twelve other recorded occurrences from 1881 forward. While unheard of, they do occasionally happen in Japan, without any help from
Tornadoes form under a certain set of weather conditions in which three very different types of air come together in a certain way. Near the
ground lies a layer of warm and humid air, along with strong south winds. Colder air and strong west or southwest winds lie in the upper atmosphere.
Temperature and moisture differences between the surface and the upper levels create what we call instability. A necessary ingredient for tornado
formation. The change in wind speed and direction with height is known as wind shear. This wind shear is linked to the eventual development of
rotation from which a tornado may form.
A third layer of hot dry air becomes established between the warm moist air at low levels and the cool dry air aloft. This hot layer acts as a cap and
allows the warm air underneath to warm further...making the air even more unstable. Things start to happen when a storm system aloft moves east and
begins to lift the various layers. Through this lifting process the cap is removed, thereby setting the stage for explosive thunderstorm development
as strong updrafts develop. Complex interactions between the updraft and the surrounding winds may cause the updraft to begin rotating-and a tornado
edit on 9/2/2013 by Zaphod58 because: (no reason given)