of course if its not weather then no whether in the world anymore so a weather is a weather
Simply because weather systems are under the influence of prevailing winds and jet streams. For example 'Nor' easters' come from the south west and swerve and hit up north East. Weather patterns are...
Extreme weather happens every where in the world when the weather gets bad.
Visit http://weather.about.com/od/forecastingtechniques/ss/mapsymbols_2.htm
The weather people are called Meteorologist - They use many instruments to predict weather including a barometer