FC: Weather Justin Cooper
1: Air Pressure An atmospheric property when the air exerts a force on air below it. Gravity causes particles of air to be pulled towards Earth's surface. As air above exerts a force on the air below, particles of air ae compressed. The compression forces air density to increase near Earth's surface. Jet Stream Differences in tempreature, pressure, and density of air produces fast, high-altitude winds. It is a body of fast moving winds in the upper atmosphere that generally move from west to east in the upper-mid latitudes. They affect the intensity of the weather systems by moving air masses from one place to another.
2: Air Masses A large body of air that takes on the characteristics of the area over which it formed. This is known as the source region. Types of Air Masses Continental tropical-dry and warm Maritime tropical-wet and warm Continental polar-dry and cold Maritime polar-wet and cold Continental arctic-dry and very cold Types of Fronts When two air masses eith different characteristics collide, a front forms. Cold front-cold air overpowers the warm air mass. Warm front-warm air overtakes the cold air mass. Stationary front-two air masses meet and stall. There are no sharp differences in temperature and pressure. Oclluded front-two cold air masses collide with warm air between them and the warm air is pushed up.
3: Types of Air Pressure When air rises or sinks due wind systems, colliding air masses, and other factors, areas of high and low pressure form in the atmosphere. High-Pressure Systems Due to the Coriolis effect, high-pressure systems in the northern hemisphere spins clockwise. Usually indicates fair weather because the air does not rise, cool and condense into clouds. Low-Pressure Systems The air in low-pressure systems moves in a counter-clockwise direction in the northern hemisphere. A low-pressure system called a wave cyclone often affects the weather across large areas in the middle latitudes, including the mid-Atlantic states.
4: Types of Global Winds The Trade Winds- They are located at 30 degrees north and south latitudes. Air sinks and moves westward toward the equator. Prevailing Westerlies- They are located at 30 and 60 degrees north and south latitude. They generally blow from the west and move eastward toward the poles. Polar Easterlies- They are found between 60 degrees latitude and the poles. they are characterized by cold air, and they flow from the northeast to the southwest in the norhtern hemisphere.
5: Types of Thunderstorms Thunderstorms develop when a cumulus cloud grows into a towering cumulonimbus cloud. Air-Mass Thunderstorms- Rises because of the unequal heating of the Earth's surface, which reaches its peak during mid-afternoon. Sea-Breeze Thunderstorms- They form in the summer in tropical and subtropical coastal regions. They are caused by sharp temperature gradients between air over land and air over water. Mountain Thunderstorms- Forms when air is lifted over a mountain. Frontal Thunderstorm- The cold air rapidly pushes warm air up a steep slope, giving rise to the conditions necessary to form cumulonimbus clouds.
6: Tornadoes A violent, whirling column of air that reaches the ground. Weak tornadoes- 80% of all tornadoes, Path up to 5 km, Wind speed 97 to 185 km/h, Duration 1-10 minutes. Strong tornadoes- 19% of all tornadoes, Path 24 km, Wind speed 177 to 330 km/h, Duration 20 minutes. Violent tornadoes-1% of all tornadoes, Path 80 km, Wind speed 322 km/h, Duration 1 hour. Safety- Move to a predesigned shelter such as a basement. If an underground shelter is not available, move to an interior room or hallway on the lowest level. Stay away from windows. Get out of automobiles. Do not try to outdistance a tornado in a car, instead, leave the car immediately. Tropical Cyclones They are large, rotating, low-pressure storms that originate over tropical waters. The storms get their energy from warm water.
7: Stages of Development First stage is a tropical disturbance. It begins to rotate around an area of low pressure and reaches the next stage, a tropical depression. When air speeds around the center exceed 65 km/h, the depression becomes a tropical storm. If air pressure continues to decrease and wind speeds reach 120 km/h, the depression is called a hurricane. Hurricane Safety Turn the refridgerator in the maximum cold setting and open it only when neccesary. Turn off all utilities if told to do so by authorities. Unplug small appliances. turn off propane tanks. Fill bathtubs and large containers with water for sanitary purposes. Storm Surges Mounds of oceans water driven by hurricane-force winds that wash over land. Water damage form hurricanes is also common farther inland, where heavy rains can cause flooding.