2 Who is the weather forecast important to? FarmersPilotsPeople with plans… headed to the park, going to watch the Tigers, have a softball gamePeople that work outsideIt is also the topic of many conversations
3 Weather ForecastingBased on observations, what predictions can you make about the weather?You could read a barometer. If the air pressure is falling, rain or snow could be on its way.Read the clouds. Cumulonimbus clouds may bring a thunderstorm. Cirrus clouds high in the sky mean low pressure area may be approaching.
4 MeteorologistsMeteorologists are scientists who study the causes of weather and try to predict it.
5 Sources of information Where do meteorologists get weather information?Local weather observers (like you!)Instruments carried by balloonsSatellitesWeather stations around the worldRadar (tracks precipitation)
6 Weather TechnologyMeteorologists can make long-range predictions because of changes in technology.Changes have occurred in two areas:Gathering weather data(weather balloons, satellites)Using computers
7 How are computers used to help forecast weather? Computer ForecastsHow are computers used to help forecast weather?Instruments gather thousands of bits of dataComputers process the information.Computer makes calculationsfor forecasts.Each forecast builds onprevious forecasts.
8 El NinoSome long-term weather patterns may be caused by changes in ocean currents and global winds.El Nino, a warm-water event, occurs in the tropical Pacific Ocean once every 2-7 years.Warm water replaces cold water.
9 Weather Service MapsData from more than 300 local weather stations all over the country are assembled into weather maps at the National Weather Service.
10 Weather Service MapsA typical reporting weather station provides you with the following data:temperatureprecipitationwind speed and directionatmospheric pressurecloud cover
11 Interpreting DataUse the key to Figure 19 (on page 103) to help you answer the questions about this weather station data.
12 IsobarsIsobars are (curvy) lines joining places on the map that have the same air pressure.Iso means “equal” and bar means “pressure”.Air pressure readings can be given in inches of mercury, in millibars, or both.
13 IsothermsIsotherms are (curvy) lines joining places that have the same temperature.The isotherm may be labeled with the temperature in degrees Fahrenheit, degrees Celsius, or both.
14 Newspaper Weather Maps Maps in newspapers are simplified versions of the maps produced by the National Weather Service.Standard symbols on weather maps show:frontstemperaturepressuretypes of precipitation
15 The Butterfly EffectA forecast for the weather six days from now is based on forecasts for all the days between now and then.A small change in the weather today can mean a larger change in the weather a week later.Why would you call this the butterfly effect?
16 Words Worth Knowing (ISN #29) MeteorologistEl NinoIsobarsIsotherms