Forecasting the Weather 3/24/14

16-4 pgs. 440-44316-4 pgs. 440-443

IN: How do meteorologists forecast the weather?

TERMS AND OBJECTIVESTERMS AND OBJECTIVES

TERMS:TERMS:

themometers themometers barometersbarometers

windsockwindsock wind vane anemometerwind vane anemometerisobarsisobars

OBJECTIVES:OBJECTIVES:

Describe the different types of instruments Describe the different types of instruments used to take weather measurements.used to take weather measurements.

Explain how to interpret a weather map.Explain how to interpret a weather map.

Explain why weather maps are useful.Explain why weather maps are useful.

Cold Front Cold Front

Weather forecastWeather forecast - a - a prediction of weather prediction of weather conditions (usually over the conditions (usually over the next 3 to 5 days).next 3 to 5 days).

Today Friday Saturday Sunday Monday

Partly Cloudy / Wind

AM Showers / Wind

Few Showers

SunnyPartly Cloudy

70°F 58° 61° 71° 76°

High High High High High

48° 43° 46° 51° 55°

Low Low Low Low Low

Chance of Precip:20%

Chance of Rain:30%

Chance of Rain:30%

Chance of Precip:0%

Chance of Precip:0%

Meteorologists use Meteorologists use special tools to measure special tools to measure various atmospheric various atmospheric conditions in order to conditions in order to accurately forecast accurately forecast weather called:weather called:

Weather InstrumentsWeather Instruments

ThermometerThermometer – instrument – instrument used to measure air used to measure air temperature. temperature.

BarometerBarometer – instrument used – instrument used to measure air pressure. to measure air pressure.

WindsockWindsock or or Wind vaneWind vane - - instrument used to measure instrument used to measure wind direction.wind direction.

AnemometerAnemometer – instrument – instrument used to measure wind speed.used to measure wind speed.

Weather in the upper atmosphere Weather in the upper atmosphere must be studied with more must be studied with more sophisticated equipment.sophisticated equipment.

Weather balloonsWeather balloons - carry - carry equipment that measures equipment that measures temperature, air pressure, temperature, air pressure, and relative humidity as high and relative humidity as high as 30 km.as 30 km.

Weather satellitesWeather satellites - orbit the - orbit the Earth and measure wind Earth and measure wind speeds, humidity, and speeds, humidity, and temperatures at various temperatures at various altitudes.altitudes.

The National Weather Service (NWS) The National Weather Service (NWS) produces weather maps based on produces weather maps based on information gathered at about 1,000 information gathered at about 1,000 weather stations across the U.S.weather stations across the U.S.

Each station is represented with a Each station is represented with a station model:station model:

Weather maps also include lines called Weather maps also include lines called isobarsisobars, which connect points of , which connect points of equal air pressure. These lines equal air pressure. These lines indicate areas of high or low indicate areas of high or low pressure.pressure.

Weather maps also label fronts, which Weather maps also label fronts, which along with isobars help to make along with isobars help to make accurate weather forecasts.accurate weather forecasts.

OUT: Why would a meteorologist compare a new weather map with one 24 hours ago?