Transcript Air MAsses
Journal W-2 1. Explain how clouds form. 2. How do we classify clouds? 3. Compare and contrast freezing rain and sleet. 4. What is dew point? TURN IN JOURNALS! Text Reference: 79-85 Journal W-3 Think about when and where clouds form. 1. Where are the high and low pressure systems on this map? 2. How do you know? 1. An air mass is a large body of air that has properties similar to the part of Earth’s surface over which it develops. 2. Air masses usually sit in one place for many days 3. Air mass names come from two properties of air masses a. Moisture content (humidity) -Air masses with moisture form over water and dry air masses form over land b. Temperature-Air masses that form at the poles are cold and the ones that form in the tropics (or near the equator) are warm. 4. 4 Categories of air masses based on moisture content and how close to the equator the air mass formed Maritime Polar Maritime Tropical Continental Polar Continental Tropical Maritime Polar Maritime Tropical 5. Highs and Lows a. Weather includes both high and low pressure systems. b. Winds move from areas of high pressure to areas of low pressure (is this familiar?). c. High-clear skies and calm air because of sinking air d. Low-fast-rising air creates clouds with rainy, stormy weather 6. Fronts-A boundary between two air masses of different density, moisture, or temperature. There are 4 kinds of fronts. *make sure you notice weather map symbols. 6a. Cold Front cold air pushes under toward warm air causing abrupt weather changes. Forms tall cumulonimbus clouds Cooler temperatures and heavy precipitation (tornadoes and thunderstorms) 6b. Warm Front Warm air slowly pushes over a cold air mass Warmer temperatures Flat stratus clouds form Can lead to hours or even days of wet weather [precipitation]. 6c. Stationary Front Occurs when a boundary between air masses stops advancing They may remain in the same place for several days producing light wind, fog and long periods of precipitation (snow or rain). 6d. Occluded Front (not found in the book!) Three air masses of different temperature collide: colder air, cool air and warm air. The colder air forces the warm air upward, closing the warm air off from the surface. Stratocumulus clouds form Long periods of precipitation occur 7. Swirling Air • Sometimes the boundaries between fronts gets distorted and it causes air to swirl in 2 ways: – Cyclone -Anticyclone >Spin CCW >Spin CW >low pressure >high pressure >Clouds, wind, >clear, dry weather precipitation Journal W-4: Diagram and name that front!