FRONTS 24-2

Fronts When 2 air masses meet density differences keep them separate Front- boundary between air masses 100’s to 1,000’s of miles wide

Cold Front Cold air mass overtakes a warm air mass Cold air lift warm air up Short lived Violent

Squall line – long line of heavy thunderstorms

Warm Front Front edge of an advancing warm air mass Cold mass retreats from an area Precipitation over a large area

Stationary Front Fronts either move very slow or don’t move

Occluded Front Cold air mass overtakes warm air mass Lift warm air up above

Polar Front Cold polar air meets warm tropical air

Midlatitude Cyclone Low pressure Rotating wind Moves towards the rising air of central low pressure regions

Midlatitude Cyclone Stages

Anticyclone Air sinks and flows outward from a center of high pressure Clockwise in NH Dry weather

Thunderstorms Heavy storm with rain, thunder, lightning, and winds 3 stages: 1. Cumulus – warm moist air rises 2. Mature – dark cumulonimbus (heavy rain) 3. Dissipating - end

Lightning Clouds discharge electricity Rapid expansion of air – thunder Lightning fun facts!

Hurricanes Tropical oceans 120 mph winds in a spiral Intense low pressure

Winds increase towards the center – eye Eye – calm sinking air Storms surge – rising sea level

Safir-Simpson Scale

Tornadoes Rotating column of air High winds Funnel-shaped 400 km/hr Thunderstorm meets a high altitude horizontal wind

Tornado Alley