Aim: How are winds created? Do Now: In your notebooks answer the following questions. Near which letter are the strongest winds located? What are the lines on this map called? A B C

I. Wind Wind: is the movement of air from high pressure to low pressure. H L

Wind is blowing from the west - Wind direction is named based on where wind comes from. N S W E Wind is blowing from the west

Wind direction is measured using a wind vane Wind speed is measured using an anemometer. If wind blows from one direction mostly, it is called a prevailing wind. * In the U.S., the westerlies constantly move weather west to east.

A large blue H indicates the center of high pressure II. Pressure Systems - Differences in temperature create differences in pressure which creates wind. 1. High Pressure System (anticyclone) Air Temperature: Moisture content: Vertical Movement: Weather conditions: Rotation: cooler dry air sinks at center Happy weather (dry/sunny) A large blue H indicates the center of high pressure

a large red L marks the center of low pressure 2. Low Pressure System (Cyclone) Air Temperature: Moisture content: Vertical Movement: Weather conditions: Rotation: warmer moist air rises at center Lousy weather (wet/cloudy) a large red L marks the center of low pressure

Low Pressure: Rotates Counterclockwise and inward to the center. High Pressure: Rotates Clockwise and Outward from the center.

III. The Coriolis Effect Curves the path of air and ocean currents across the Earth. Caused by the rotation of the Earth Northern Hemisphere = curved to the right Southern Hemisphere = curved to the left

Cyclones and anticyclones move in the opposite direction in the Southern Hemisphere.

IV. Weather Forecasting Weather reports emphasize the locations and possible paths of cyclones and anticyclones (High and Low pressure). * Low-pressure centers can produce bad weather in any season.

Closure 1: In your notes, list the characteristics for high and low pressure systems. H L High Pressure Heavy Air (Sinking) Happy Weather Clockwise Out Low Pressure Light Air (Rising) Lousy Weather Counterclockwise In

Take a “How do Winds Form” worksheet from the back bottom bin. Closure 2: Take a “How do Winds Form” worksheet from the back bottom bin. Complete both sides.