1 Forecasting the Weather

Weather Weather: The daily conditions of a particular area: temp, rain, pressure, wind, etc.Weather: The daily conditions of a particular area: temp, rain, pressure, wind, etc. Climate: the measure of weather over a very long period of time—at least 100 yearsClimate: the measure of weather over a very long period of time—at least 100 years Meteorology- the science of studying weatherMeteorology- the science of studying weather 2

3 What is a weather forecast? Forecast: A prediction of weather over the next 3-5 days.

4 What is a meteorologist? Meteorologist: A person who observes the atmosphere, collects data, and makes predictions— forecasts—based on the data. Meteorologist = weather person You know them as weathermen and weatherwomen.

5 What do meteorologists measure? Air pressure Humidity Precipitation Temperature Wind speed Wind direction

6 Weather balloons Pictures courtesy of

Weather Instruments Anemometer Wind Sock Thermometer Barometer Doppler Radar Weather Satellite 7

8 Weather Balloons Weather balloons: Carry equipment as high as 30 km above the Earth’s surface Measure temperature, air pressure, relative humidity, wind speed, & direction

9 Thermometer Thermometer: Used to measure: –air temperature

10 Barometer Barometer: Used to measure air pressure

Psychrometer An instrument used for measuring the water vapor content of the atmosphere; a type of hygrometer. water vapor hygrometerwater vapor hygrometer

12 Anemometer Used to measure wind speed

13 Wind Sock Used to measure wind direction

14 Wind Vane/Weather Vane Used to measure wind direction

15Radar Used to find location, movement, kind & amount of precipitation

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17 Weather Satellite Orbit the Earth & send information back to Earth; used to track storms, wind speed, humidity, & different altitudes

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19 Collecting & Analyzing Weather Data 2 groups who gather information: –National Weather Service (NWS) –NOAA (National Oceanographic & Atmospheric Administration)

20 NWS Produce maps based on information gathered from over 1,000 weather stations nationwide

21 Station Model A small circle that shows the location of a weather station Surrounding the small circle is a set of symbols & numbers that represent weather data

22 Example of a Station Model

Weather Map Symbols Cold Front Warm Front Occluded Front Stationary Front High Pressure Clear Weather Low Pressure Cloudy Weather Isobars: Show equal Lines of Pressure. 23

24 Cold Front Represented by triangles on a line

25 Warm Front Represented by half-circles on a line:

26 High Pressure Usually brings clear, sunny weather

27 Low Pressure Bring rainy weather

28 Isobars Lines that connect points of equal pressure on a weather map

ISOBARS- Certain weather maps allow us to view High and Low pressure systems that control the weather. An isobar is a line connecting locations of equal barometric pressure. Isobar maps show where pressures are relatively high and low, and show us where pressure changes are gradual or dramatic over a distance. 29

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