Aim: How are winds created?

Do Now: In your notebooks answer the following questions.

1)Near which letter are the strongest winds located?

2)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 direction is named based on where wind comes from.

W E

N

S

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.

II. Pressure Systems- Differences in pressure creates wind.

1. High Pressure System (anticyclone)

Air Temperature: Moisture content:Vertical Movement:Weather conditions:Rotation:

A large blue H indicates the center of high pressure

coolerdry air

sinks at centerHappy weather (dry/sunny)

a large red L marks the center of low pressure

2. Low Pressure System (Cyclone)

Air Temperature: Moisture content:Vertical Movement:Weather conditions:Rotation:

What type of pressure system was most likely in RVC yesterday?

How about today?

warmermoist air

rises at centerLousy weather (wet/cloudy)

High Pressure: Rotates Clockwise andOutward from the

center.

Low Pressure: Rotates

Counterclockwise andinward to the center.

- 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

III. The Coriolis Effect

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:• In your notes, list the characteristics

for a low pressure system and a high pressure system.

H

L

• High Pressure• Heavy Air (Sinking)

• Happy Weather• (clear skies)• Clockwise

• Out• Low Pressure

• Light Air (Rising)• Lousy Weather

• (clouds & precip.)• Counterclockwise

• In