1. 25.3 Weather Instruments Wind vane – most common, located on
Winds are always labeled from the direction from which they blow.
Wind vane – most common, located on
buildings; always point into the wind.
Anemometer – measures wind speed
and direction
Draw N -0°, E 90°, S 180°, W 270° ; arrow clockwise

2. Weather Satellites Weather Balloons Doppler RADAR Measuring Upper -
Atmospheric conditions
Doppler RADAR
Radio wave pulses
Particles of water bounce back

3. Normal conditions
El Niño and La Niña
(4:30)
El Niño - Normally cold offshore waters are replaced by unusually strong warm equatorial waters
El Niña – atmospheric phenomenon when surface temperatures of the eastern Pacific are colder than average; blows cold air over the Pacific NW & plains, but warms the rest of the U.S.

4. 25.4 Forecasting the Weather
How to read weather maps:

5. Isobars
Iso = equal
Bar = pressure
Pressure flows ‘around’ the pressure center
counter clockwise around lows
clockwise around highs
The closer the isobars, the stronger the winds

6. Low pressure system:
Increased clouds, winds,
Chance of rain
High pressure system:
Clear calm conditions with reduced chance of rain.
Drier air results in greater range of H and L temps.

8. Turn to pages 513-514 in your text.
Learn the symbols.
Interpret the maps!