weather

2. this is used to measure air pressure
6. a tropical storm with winds that have reached a constant speed of 74 miles per hour or more
11. marks the boundary between two air masses
14. when a relatively moist, warm air mass slides up and over a cold air mass
16. the noise heard after a lightning flash due to the expansion of rapidly heated air
18. a severe snowstorm with high winds and low visibility

1. when a cold air mass pushes into a warmer air mass
3. used to assign a tornado a rating
4. an instrument used to measure temperature
5. an instrument used to measure wind
7. a multicolored arc made by light striking water droplets
8. ice pellets, often mixed with rain or snow
9. a violently rotating column of air touching the ground, usually attached to the base of a thunderstorm
10. water vapor frozen into ice crystals and falling in light white flakes
12. a type of precipitation that falls in visible drops
13. precipitation that comes down as balls of ice
15. a sudden light fall of snow, blown in different directions by the wind
17. a prolonged period of abnormally hot weather