16.3 STORMS

Learning Targets 1.Describe how atmospheric circulation patterns cause storms to form and travel 2.Understand the weather patterns that lead to tornadoes, and identify the different types of cyclones 3.Know what causes a hurricane to form, what causes it to disappear, and what sorts of damage it can do 4.Know the damage that heat waves and droughts can cause

Formation of Storms 1.Vapor  liquid a)Releases latent heat; storm grows 2.Liquid  vapor a)Absorbs latent heat; storm weakens

Latent Heat

Thunderstorms 1.Ground is hot a)Summer afternoons b)Strong updrafts as hot air rises 2.Water vapor condenses  Clouds 3.Convection cell occurs inside cloud a)Hail if drafts in clouds are very strong

Squall Lines 1.Long lines of storms along a cold front a)Can stretch for 1000s of miles 2.Summer mT air mass meets cP air mass a)Causes tornadoes

Lightning 1.Energy collects in cumulonimbus cloud and releases as lightning 2.Part of clouds get positive (+) charge; part gets negative (-) charge 3.Lightning equalizes this difference 4.Extremely hot  hot air expands 5.Quickly expanding air makes noise a)Thunder

Lightning Formation

Tornadoes 1.As air rises in thunderstorm, surrounding air rushes to fill gap forming a funnel 2.Squall lines form in spring where mT and cP meet 3.Extreme winds a)Average ~110 mph b)Maximum of over 300 mph 4.Measured on Fujita scale 5.Cannot predict where & when

Cyclone 1.Winds rotate counterclockwise around a L a)Clockwise in Southern Hemisphere 2.Mid latitude cyclones a)Nor’easters (New England States) 3.Tropical cyclones a)Hurricanes

Airflow Patterns, Surface and Aloft

Tropical Cyclones 1.Hurricanes, typhoons same thing a)Measured on Saffir-Simpson Scale 2.Warm ocean water causes Low pressure cell 3.Vapor to liquid releases heat  more L 4.Begins to spin as heat builds up

Tropical Cyclones 1.Huge amounts of rain 2.Strong winds a)Usually not as strong as tornadoes 3.Storm surge a)Tidal surge can flood coastal regions

Blizzards & Lake Effect Snow 1.Blizzards are extreme snow storms characterized by: a)Temperatures below -7º C (20º F) b)Winds greater than 56kmph (35mph) c)Visibility is less than ¼ mile for at least hours 2.Lake effect snow: cold dry air passes over a warm lake (Great Lakes) and picks up moisture. Huge quantities of snow fall on the leeward side of the lake a)Not a blizzard

Heat Waves 1.Extreme heat that lasts longer than normal a)High pressure zone traps hot air near the ground 2.Heat waves kill more people each year than any storm