Weather Forecasts

Data collected from the atmosphere The National Weather Service counts on two sources for information: Data collected from the atmosphere Data collected from the Earth’s surface Weather Balloon Radar Weather balloons are used to collect data from the atmosphere. They have different instruments attached to them that will record temperature, humidity, air pressure, etc. Radars are used to collect data from the Earth’s surface.

In order to forecast the weather, meteorologists make measurements of: temperature winds air pressure humidity precipitation Meteorologists are people who study the weather. They collect data in order to forecast weather.

Instruments used to measure precipitation: Rain Gauge Snow Gauge

Instrument used to measure temperature: Thermometers

Instrument used to measure humidity: Psychrometer

Instrument used to measure wind speed Anemometer

Instrument used to measure wind direction: Wind Vane

Instrument used to measure air pressure: Barometer

When meteorologists gather up data, it is recorded on a map using a combination of symbols, forming a STATION MODEL. After collecting data, meteorologists create station models.

Isobars are lines that connect equal atmospheric pressure . Meteorologist use the air pressure measurements to identify areas of high and low pressures. They are represented in a map as isobars.. These lines show the areas of high and low pressure.

L Pressure Changes with Temperature Air flows in a clock-wise direction on the surface of the Earth. Cold, dense air sinks to the surface of the Earth. Airs flows in a counter clock-wise direction at the surface of the Earth. L Warm, less dense air rises forming clouds Pressure Changes with Temperature

Pressure Gradients There are many areas of high and low pressure above the Earth’s surface due to uneven surface heating creating pressure gradients.

Air moves from high pressure to low pressure forming winds.

The closer the isobars, the stronger, the winds blow. The more spread out the isobars, the gentler the winds.

Fronts are draw as lines and symbols. Using the station models meteorologists can then predict or forecast the weather. They use computers to create weather maps using a combination of symbols.

H L What will happen to the weather in Denton? Which direction is the warm front moving? 25°C 28°C L H 40°C 29°C 45°C Warm Front H High Pressure Occluded Front L Low Pressure Cold Front Stationary Front

The closer the isobars, the stronger the winds blow. STATION MODEL is created when data that is collected is recorded on a map using a combination of symbols. Symbols for Fronts The closer the isobars, the stronger the winds blow. The more spread out the isobars the gentler the winds. Isobars are lines that connect equal atmospheric pressure . There are many areas of high and low pressure above the Earth’s surface due to uneven surface heating creating pressure gradients. Air moves from high pressure to low pressure forming winds. Air flows in a clock-wise direction on the surface of the Earth. Cold, dense air sinks to the surface of the Earth. Airs flows in a counter clock-wise direction at the surface of the Earth. L Warm, less dense air rises forming clouds Cold, dense air sinks to the surface of the Earth Warm, less dense air rises forming clouds Air flows in a clock-wise direction on the surface of the Earth in High Pressure areas. Airs flows in a counter clock-wise direction at the surface of the Earth in Low Pressure areas.