Weather%20Forecasting

1
Weather Forecasting

• 2009

2
Predicting the weather
A ring around the sun or moon, means that rain
will come real soon.

• People have needed to predict the weather since
  the dawn of time.
• Hunting, farming, and all outdoor work depends on
  the weather.
• Folklore grew around the observations people made.

Red sky at night, sailor's delight red sky in
the morning, sailor's take warning.
3
Modern Forecasting

• Relies on
• Observation using various instruments
• Computer models
• Previous trends and patterns in the weather.
• Can be accurate up to five days in the future.

4
Trends and Patterns

• Meteorologists Scientists that study the causes
  of weather and try to predict it.
• They use data collected over the past 100 or more
  years to make their predictions.
• So when they say There is a 40 chance of rain
  today, they mean that in the past, when the
  conditions were similar, it rained 40 of the
  time.

5
Weather Instruments

• A thermometer measures temperature.A barometer
  measures air pressure.A rain gauge measures
  precipitation.An anemometer measures wind speed.
• Weather vanes find wind direction.
• A psychrometer measures relative humidity.

6
Weather Technology

• New technologies have made short range (2 to 5
  days or so) forecasting fairly reliable.
• They are now working on long range predictions.
• Changes in technology are making this possible
• Satellites and computers.

7
Computer Models

• Computers can take millions of pieces of data and
  process this information to make predictions.
• Predictions are only as good as the computer
  model.

8
Weather Radar

• Uses Doppler radar to track moving storms and
  precipitation.
• NEXRAD is the new generation Doppler radar that
  tracks wind and precipitation.
• This allows tornadoes to be accurately tracked.

9
Weather Balloons

• Weather balloons carry equipment up to 30 kms
  high
• A radiosonde attached to a weather balloon
  measures weather high in the atmosphere.
• This equipment records data and sends it to
  weather stations

10
Weather Satellites

• A lot of data comes from satellites
• They take pictures of the earth from outer space.
• They can also collect data on temperature, cloud
  height, and moisture.
• Then the satellites send their data to weather
  stations

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Weather Maps

• There are many different kinds of weather maps.
• Data from local weather stations from all over
  the country is collected to create national
  weather maps.

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Temperature Map

• Shows the current temperatures.

13
Radar Maps

• Shows precipitation.

14
National Wind Map

• Shows wind speed and direction.

15
Infrared Satellite

• Shows cloud top temperature.

16
Fronts
17
Visible Satellite

• Shows picture from space.

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Precipitation

• Shows precipitation in inches.

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Humidity

• Shows the relative humidity.

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Isobars

• Show areas of equal pressure.
• Inner most circles will be the low or high
  pressure areas.

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Isotherms

• Lines show areas of equal temperature.
• Isotherm maps show where temperatures are
  relatively high and low, and also where
  temperature changes are gradual or dramatic over
  a distance.

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NWS and Maps
Chapter 16
Weather Maps

• The National Weather Service produces weather
  maps based on information gathered from about
  1,000 weather stations across the United States.

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Weather Map Symbols

• These are the symbols you would see on a weather
  map.
• The arrows or bumps point in the direction the
  front is moving.