Forecasting the Weather 3/24/14 16-4 pgs. 440-443 IN: How do meteorologists forecast the weather?

TERMS AND OBJECTIVES TERMS: themometers barometers windsock wind vane anemometer isobars OBJECTIVES: Describe the different types of instruments used to take weather measurements. Explain how to interpret a weather map. Explain why weather maps are useful.

Cold Front

Weather forecast - a prediction of weather conditions (usually over the next 3 to 5 days). Friday Saturday Sunday Monday Partly Cloudy / Wind AM Showers / Wind Few Showers Sunny Partly Cloudy 70°F 58° 61° 71° 76° High 48° 43° 46° 51° 55° Low Chance of Precip: 20% Chance of Rain: 30% Chance of Precip: 0%

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

Thermometer – instrument used to measure air temperature.

Barometer – instrument used to measure air pressure.

Windsock or Wind vane - instrument used to measure wind direction.

Anemometer – instrument used to measure wind speed.

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

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

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

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

Each station is represented with a station model:

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

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

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