Download 25.4 Forecasting the Weather

25.3
Weather Instruments
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
Weather Balloons
Weather Satellites
Measuring Upper Atmospheric conditions
Doppler RADAR
Radio wave pulses
Particles of water bounce back
El Niño and La Niña
New Text p. 546-547
El Niño - Normally cold offshore waters
are replaced by unusually strong warm
equatorial waters (Read p. 546)
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.
Normal conditions
25.4
Forecasting the Weather
www.projectsharetexas.org/node/12016
How to read weather maps:
www.youtube.com/watch?v=bd7DcVnrSL8
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
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.
Turn to page 534 in your
Text. Learn the symbols.
Interpret the maps!