3.1 Weather Changes as air masses moves.

1. 3.1 Weather Changes as air masses moves. Done by: Faisal Al Najem 8-3

2. Air Masses are large bodies of air. An air mass is a large volume of air in which temperature and humidity are nearly the same in different locations at the same altitude. An air mass forms when the air over a large region of earth sits in one place for many days. When earth’s surface is cold, the air becomes moist. When earth’s surface is dry the air become’s also dry.

3. Characteristic of air mass. The characteristics of an air mass depend on the region where it forms. A hot desert produces dry, hot air masses, while cool ocean waters produces moist, cool air masses. Scientists rate air masses into categories according to the characteristics of regions.

4. Characteristics of air mass There are four types of Characteristics, and they are: Continental Maritime Tropical Polar

5. Continential air mass Continental: Air masses form over land. Air becomes dry as it loses it’s moisture to the dry land below it.

6. Maritime air mass Maritime: air masses form over land. Air becomes moist as it gains water vapor from the water below it.

7. Tropical air mass Tropical: air masses from near the equator. Air becomes warm as it gains energy from the warm land or water.

8. Polar air mass Polar: Air masses form far from the equator. Air becomes cool as it loses energy to the cold land or water.

9. Movement of an air mass Air masses can travel away from the regions where they form. They move with the global pattern of winds.

10. Movement of an air mass When air mass moves to a new region, it carries along it’s characteristics moisture and temperature. As air moves over earth’s surface, the characteristics of the surface begin to change.

11. Weather changes where air masses meets When a new air mass moves over your area, you can expect the weather to change. Front: is a boundary between air masses

12. Fronts and weather Different types of fronts produce different types of weather. When a cold, dense air mass pushes warmer air, it produces a cold front. When a warm air mass pushes colder air, it produces a warmer front.

13. Types of fronts Cold Front forms when cold air mass pushes a warm air mass and forces the warm air to rises, It’s moisture condenses and forms tall clouds

14. Types of fronts Warm front forms when a warm air mass pushes a cold air mass. The warm air rises slowly over the cold air and its moisture condenses into flat clouds.

15. Types of Fronts Stationary Fronts occurs when two air masses push against each other without moving. A stationary front becomes a warm or cold front when one air mass advances.

16. High pressure system A high pressure system is formed when air moves all the way around a high pressure center. Most high pressure system are large and change slowly.

17. Low pressure system A low pressure system is a large weather system that surrounds a center of low pressure. It begins as air moves around and inward toward the lowest pressure and then up to highest altitudes.

18. 3.2 Low pressure systems can become storms

19. Hurricanes form over warm ocean water Near the equator, warm ocean water provides the energy that can turn a low-pressure center into a violent storm.

20. Hurricanes form over warm ocean water Tropical storm is a low-pressure system that starts near the equator and has winds that blow at 65 kilometers per hour and 40 mi per h and more Hurricane is a tropical low pressure system with winds blowing at speeds of 120 kilometer per hour 74 mi/h or more – strong enough to uproot trees

21. Formation of hurricanes Energy from warm water is necessary for a low-pressure center to build into a tropical storm and then into a hurricane.

22. Effects of hurricanes A hurricane can pound a coast with huge waves and sweep the land with strong winds and heavy rains. Also hurricane wind can lift cars, uproot trees, and tear the roofs of buildings. Storm surge often pushes a huge mass of ocean water. A storm surge can be destructive and deadly.

23. Winter storms produce storms and ice Blizzardsare strong winds that can blow so much snow into the air at once that it becomes difficult to see and dangerous to travel. They are also blinding snowstorms with winds of at least 56 kilometer per hour 35 mi/h and low temperatures-usually below -7c 920f. Lake-Effect Snowstorms is some of the heaviest snows fall in the area just east and south of the great lakes. Ice storms is when rain falls onto freezing-cold ground, conditions can become dangerous.

24. Thank you for listening