I don't know what science subject to put this in but its Earth and space science.. Please help?!

A barometer in a city shows a sudden fall in the mercury level. What type of weather is most likely expected in the city?
A. snow
B. storm
C. heavy rainfall
D. fair weather

Question

I don't know what science subject to put this in but its Earth and space science.. Please help?!

A barometer in a city shows a sudden fall in the mercury level. What type of weather is most likely expected in the city?
A. snow
B. storm
C. heavy rainfall 
D. fair weather

math&ing001 · Answer

A sudden fall in the mercury level usually indicates an upcoming storm that won't last for long. Read all about it here : http://weather.about.com/od/weatherinstruments/a/barometers.htm