Wind & Weather Basics March 2014. Weather is always changing ! Constant movement of air Changes in...
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Transcript of Wind & Weather Basics March 2014. Weather is always changing ! Constant movement of air Changes in...
Wind & WeatherBasics
March 2014
Weather is always changing !
• Constant movement of air• Changes in moisture
Air Mass
• Large body of air that has the same properties as the surface over which it develops.
–Cold, Hot - Wet, Dry • These air masses move across the U.S. &
collide with each other creating fronts ….
Types of Air Masses
Weather Maps
Tuesday & Wednesday
Isotherms
Isobars
http://www.aos.wisc.edu/~aalopez/aos101/wk3/wk3Pcont.jpg
How does weather affect you?
• Directly– Rain – floods/drought– Snow – closes school– Ice – no power– Tornado – destructive
• Indirectly– Drought – food prices go up– Freeze in South – fruit is destroyed – Cold Weather – oil & gas prices go up
What determines what the weather will be today?
• Air pressure
• Wind
• Temperature
• Humidity
Wave Cyclones
• Low pressure areas• Start to rotate
counterclockwise• Bad weather• Thunderstorms & rain
•
Air Pressure
• Low Pressure• Few molecules in the
air
• “sucks in” bad weather
Hurricanes = Tropical cyclones
• Also known as typhoons• Speeds in excess of 120
km/hr
•
Thunderstorms
Tornadoes
Anticyclones
• High pressure areas• Dry/clear weather• Droughts
"High pressure is good; sunny weather occurs when the pressure is high. Skies are blue, winds are light and it never rains when the barometer soars."
Air Pressure
• High PressureLots of molecules in the air
“pushes away” the bad weather
Complete Venn Diagram for High & Low Pressure Systems
03/22/2001 - Updated 02:02 PM ET
Source: USA TODAY research by Chad Palmer, Graphic by John He
03/22/2001 - Updated 02:36 PM ET
Source: USA TODAY research by Chad Palmer, Graphic by John Herne
Occluded Fronts2 cold air mass meet
Pushing up the warm air that is blocked in-between.
03/22/2001 - Updated 02:29 PM ET
Stationary Front
Each Front causes precipitation
Along each front warm air is pushed upward, cooled in the atmosphere,
and becomes saturated
Types of Fronts
Start here on Wednesday
Weather Instruments & forecasts
Anemometer Measures wind speed
Wind
• Comes from North=> Cold
• Comes from South=> Warm
Fast or Slow ???
Weather Radar = Doppler Radar
Measuring air pressure with a barometer
Humidity
Hot air can hold more water vapor
Cold air is drier& causes static electricity in winter
Measured with a psychrometer, hygrometer, or a
Relative Humidity
• The amount of water vapor in the air compared to how much it could hold.
ex.) 50%, 20%
• Saturated means 100%
• Measured with a psychrometer.
Radiosonde = package of weather
instruments
Climate: predictable weather patterns