1.Weather – the condition of the earth’s atmosphere 2.Relative humidity – a measure of the amount of water vapor in the air compared with the amount of water vapor the air can hold. 3.Dew point – the point when water vapor in the air cools down and condenses 4.Barometric pressure – amount of pressure caused by the atmosphere 5.Doppler radar - detects wind velocity and precipitation  Definitions

6.Precipitation – rain, snow, sleet, hail, and freezing rain 7.Clouds – water vapor that condenses up in the air 8.Isobar – lines that are drawn to connect areas that have equal barometric pressure 9.Conduction – the transfer of heat between objects 10.Radiation – transfer of energy in electromagnetic waves  Definitions cont…

 Definitions cont… 11.Convection – transfer of heat in a fluid from a warmer area to a cooler area 12.Evaporation – liquid changes into gas 13.Coriolis effect – the deflection of wind 14.Gust – sudden increase in wind velocity 15.Storm surge – an unusually high rise in the level of the ocean that brings a wall of water to the shoreline

Types of Weather Fronts  Cold Front = an area of colder temperatures moving into an area  Warm Front = an area of warmer temperatures moving into an area  Stationary Front = When a warm or cold front stops moving.  Occluded front = When a cold front takes over a warm front

Mov24.mpg

Mov27.mpg

Mov30.mpg

 Knowing the temperature is required to make predictions.  Always measure the current temp. about 6 feet off of the ground and in the shade.  The amount of moisture in the air is called humidity.  Different cloud types can help you predict changes in weather patterns.  Relative humidity measures temp and humidity

 High-Level Clouds Cirrus Clouds  Mid-Level Clouds Altus Clouds  Low-Level Clouds Stratos Clouds  Various Clouds Cumulus Clouds

 Isolated clouds in the form of delicate, white threads.  These clouds have a fibrous appearance, silky sheen, or both.  Clouds are found high in the sky (high-level)

 Altos clouds are caused by a convection.  They are a warning of an approaching cold front.  On a humid summer morning, they indicate a thunderstorm will occur later in the day.

 Stratus clouds are dark, low-level clouds accompanied by light precipitation.  When temperatures are cold enough, these clouds may contain ice particles and snow.

 Cumulus clouds are small clouds that look like lumps of cotton.  Cumulus clouds form as water vapor condenses in strong, upward air currents above the earth's surface.water vaporcondenses  These clouds usually have flat bases and lumpy tops.lumpy tops

1.Tornado, funnel cloud 2.Thunderstorm in area (no rain at station) 3.Thunderstorm with rain 4.Snow thunderstorm 5.Thunderstorm with freezing rain 6.Thunderstorm with hail or ice 7.Severe thunderstorm in area (no rain at station) 8.Severe thunderstorm with rain 9.Severe snow thunderstorm 10.Severe thunderstorm with freezing rain

11. Severe thunderstorm with hail or ice 12. Moderate freezing rain 13. Light freezing rain 14. Rain shower 15. Light rain shower 16. Light rain 17. Moderate rain 18. Heavy rain 19. Light snow shower 20. Snow shower

21. Light snow 22. Moderate snow 23. Heavy snow 24. Rain mixed with hail or ice pellets 25. Hail or ice pellets 26. Moderate freezing drizzle 27. Light freezing drizzle 28. Light drizzle, mist 29. Moderate drizzle 30. Heavy drizzle

31. Light Hail 32. Hail or ice pellet shower 33. Ice crystals 34. Fog 35. Blowing snow, blizzard 36. Blowing sand 37. Rain-snow mixture 38. Lightning 39. Smoke, smog

Station Symbols The weather symbol highlighted in yellow indicates the type of weather occurring at the time the observation is taken. In this case, fog was reported. If there were thunderstorms occurring when the observation was taken, then the symbol for thunderstorms would have appeared instead.weather symbol

Station Symbols Temperature: The value highlighted in yellow located in the upper left corner is the temperature in degrees Fahrenheit. In this example, the reported temperature is 64 degrees.Temperature: temperature

Dew Point Temperature: The value highlighted in yellow located in the lower left corner is the dew point temperature in degrees Fahrenheit. In this example, the reported dew point temperature is 58 degrees.dew point temperature

Cloud Cover: The symbol highlighted in yellow indicates the amount of cloud cover observed at the time the observation is taken. In this case, broken clouds were reported.cloud cover

Sea Level Pressure: The value highlighted in yellow located in the upper right corner represents the last three digits of the sea level pressure reading in millibars (mb).sea level pressure

Wind Barb: The symbol highlighted in yellow is known as a wind barb. The wind barb indicates wind direction and wind speed.wind barb

CLOUD COVER FRONTS AND PRESSURE CLOUD TYPESWIND DIRECTION & SPEED

© 2001 WSI Corporation All rights reserved. Home | About | Advertising | Affiliates | Contact | Help | LegalWSI Corporation HomeAboutAdvertisingAffiliatesContactHelpLegal

Exploding Thunderhead Tucson Arizona