Atmospheric Movement and Local Weather
*Fronts
*When convection and winds cause air masses to move, they bump into one another.
*The area where two air masses meet is called a front.
*Most severe weather occurs near frontal boundaries.
*Cold Front- Cold air meets warm air- Fast moving and stormy, severe weather is likely
*Moves in the Direction of the
Triangles
*Cold, dense air is moving toward warm, less dense air.
*The warm air is pushed up to cool and form clouds as the cooler air replaces it.
*The air on the front side of the boundary line is warmer than the air on the back side of the boundary line.
*These fronts are usually fast moving and bring stormy weather and heavy precipitation followed by clearing skies and higher pressure.
*Warm Front- Warm air meets cold air- Slow moving with less severe weather
*Moves in the Direction of the
Semi-Circles
*Warm air is moving toward cold air.
*The warm, less dense air slides over the cold, more dense air.
*The air on the front side of the boundary line is cooler than the air on the back side of the boundary line.
*These fronts usually move slowly and bring steady rain or snow over many days.
*Stationary Front
*Warm and cool air masses that are not strong enough to move one another
*Sits still for a long period of time
*Stationary Front Symbol
*Stay in One Area
*These fronts occur when neither the cool nor warm air masses are strong enough to replace each other.
*They tend to stay in an area for a long period of time, often bringing long periods of precipitation and clouds.
*Occluded Fronts
*Two cooler air masses meet and force a warm air mass aloft.
*Brings cool temperatures and large amounts of rain or snow.
*Followed by clear skies and drier air.
*Occluded Front Symbol
*Occluded Fronts
*This is when a warm air mass is caught between two cold air masses.
*The colder air mass moves under the warm air mass and pushes it up.
*The colder air mass then moves forward until it meets a cold air mass that is warmer and less dense.
*The colder air mass moves under this air mass and pushes it up.
*Brings clear skies and drier air.
*Sea Breeze and Land Breeze
Simulation
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1903/es1903page01.cfm?chapter_no=visualization
*Land and Sea Breezes
*The heating and cooling of water and land produces land breezes and sea breezes.
*High pressure moves toward low pressure, pushing the warm air upward.
*As warm air rises, cooler air moves in and replaces it.
*The Earth’s Insulator
*The Sun heats the water and land every day.
*Land heats up rapidly, but cools off rapidly.
*Desert
*Water heats up slowly, but cools off slowly.
*Swimming at night
*The heat retained by the oceans is what keeps our planet insulated.
*Weather Maps
*Weather Maps
*Weather is the atmospheric condition at a certain time and place.
*Weather maps are used to show current weather conditions in an effort to predict future weather conditions.
*You need to know what each symbol means and how to interpret them to forecast the weather.
*Air Pressure and Wind
*Air pressure is measured with a barometer in millibars.
*Millibars are represented by connected lines of equal pressure. This is a lot like the topographic map lines.
*The closer together the lines are, the faster the wind speed.
*The farther apart the lines are, the slower the wind speed.
*High Pressure
*Moves toward Low Pressure
*Cooler, dense air close to the surface of the Earth.
*Surrounded by winds flowing in a clockwise direction.
*Usually brings dry conditions and fair skies.
*Low Pressure
*High pressure will move toward low
pressure.
*Warmer, less dense air above the Earth’s surface
*Surrounded by winds moving in a counterclockwise direction.
*Associated with the formation of storms.
*High and Low Pressure Circulation
*Pressure Force
*Front symbols you may see on a
weather map