7th grade science standards E.ES.07.72- Describe how different weather occurs due to the constant motion from the atmosphere. E.ES.07.74- Describe weather conditions associated with frontal boundaries and movement of major air masses and the jet stream across North America using a weather map.
Weather Condition of the air on earth The sun determines our weather Water evaporates into the air Causes our air to rise Fronts and Air Masses
Air Masses Large body of air Have similar properties Can be tracked over time Gives us clues to future weather
Air Masses Different air masses don’t usually mix Boundary, or front, forms between masses Stormy weather often occurs along fronts
Cold Fronts Cold air moves into warm air The cold air becomes more dense Pushed under warm air Cumulus clouds and showers occur Winds change directions, temperature drops
Warm Fronts Warm air moves into cold air Pushed above cold air Cirrus and possibly stratus clouds form Some participation, rain or snow Air pressure and temperature rise
Stationary Front Sometimes air masses don’t move Variety of weather occurs Usually clouds with light precipitation Dissipate after several days
Questions What is an air mass? What happens in a cold front?
High Pressure Area’s Shown by “H” symbols Pressure is greater then surrounding areas Air pressure difference results in wind
Low Pressure Area’s Shown by “L” symbols Winds blow into low pressure zones Incoming winds cause clouds and precipitation
Using a Weather Map Red arrows are warm fronts Blue arrows are cold fronts “H” high pressure zones “L” low pressure zones
Predicting Weather Predict with great deal of accuracy Weather moves from west to east Geographic conditions can affect local weather
Credits Axel Rouvin, CG lightning strike, January 18th 2007, Attribution NOAA, Weather Map, December 14th 2003, Public Domain Lisa Gardiner, Windows To The Universe, September 30th 2010, Attribution Share-Alike
Credits Wikimedia, Weather Map Symbols, September 30th 2010, Attribution Share-Alike