FACTORS INFLUENCING WEATHER SC.5.E.7.3 Recognize how air temperature, barometric pressure, humidity, wind speed and direction, and precipitation determine the weather in a particular place and time. . FACTORS INFLUENCING WEATHER Today, we are going to learn about the factors that influence weather. Most weather changes occur in the lower atmosphere of the earth called the troposphere and are a direct result of the combination of the amount of heat, moisture, and dry movement in the air. SC.5.E.7.4 Distinguish among the various forms of precipitation (rain, snow, sleet, and hail), making connections to the weather in a particular place and time.

What is weather? The condition of the atmosphere at a particular place and time. Weather is defined as the condition of the atmosphere at a particular place and time.

Factors Determining Weather Air Temperature Barometric Pressure Humidity Wind Speed and Direction Precipitation So, exactly which factors affect weather? Well, there are five factors that influence weather including: air temperature, barometric pressure, humidity, wind speed and direction, and precipitation.

AIR TEMPERATURE Due to the unequal heating of the atmosphere by the Sun Cloud cover affects the temperature of the air Air Temperature varies greatly due to the unequal heating of the atmosphere by the Sun. As the Sun revolves and rotates on its axis, different parts of the Earth receive varying degrees of sunlight. The air temperature is measured using a thermometer. Cloud coverage is another factor that affects the temperature of the air. When the skies are cloudy the Sun's rays are reflected off the clouds back into space and the air temperature decreases. On the other hand, when there are fewer clouds, more heat reaches the Earth's, leading to warmer temperatures. Warmer temperatures will cause more moisture to be held in the air. When the warm air rises, cools, and reaches the point at which no more moisture may be held in the air, it is more likely to fall as precipitation. Measured using a THERMOMETER

The measure of the weight of gases in the atmosphere AIR PRESSURE The measure of the weight of gases in the atmosphere The pressure decreases as the altitude increases Air Pressure (barometric pressure) is the measure of the weight of gases in the atmosphere. The pressure of the atmosphere is measured with an instrument called a barometer. The pressure decreases as the altitude increases. There is more evaporation when the air pressure is low. There is more evaporation when the air pressure is low Measured using a BAROMETER

The amount of water vapor or moisture content in HUMIDITY The amount of water vapor or moisture content in the air at a specific time Determines the likelihood of precipitation, dew, or fog Humidity is the amount of water vapor or moisture content in the air at a specific time. Humidity is a major factor of changing weather conditions. Humidity determines the likelihood of precipitation, dew, or fog. The moisture content in the air causes clouds to form. When the water vapor in the air becomes too heavy it falls to the ground in the form of rain, snow, sleet, or hail. Humidity is measured using a hygrometer. Measured using a HYGROMETER

WND SPEED AND DIRECTION Wind speed is measured using a ANEMOMETER Wind is caused by the uneven heating of the Earth causing air to flow from high pressure to low pressure zones Wind Speed and Direction is influenced by many factors. Wind is caused by the uneven heating of the Earth causing air to flow from high pressure to low pressure zones. The closer the high and low pressure areas are together, the stronger the "pressure gradient", and the stronger the winds. Earth's rotation also affects wind causing currents in the Northern Hemisphere to move to the right, while currents in the Southern Hemisphere are moved to the left. This phenomenon is known as the Coriolis Effect. Wind speed is measured using an anemometer and is typically measured in miles per hour (mph). Wind direction is one of the most recorded measurements in meteorology today. It is measured using a wind vane which is a tool that works by swinging around in the wind to show the direction of the blowing wind. Wind speed is measured using a ANEMOMETER

The falling of water from the atmosphere to the surface of the Earth PRECIPITATION The falling of water from the atmosphere to the surface of the Earth Reaches the ground in the form of solid or liquid water Precipitation is the falling of water from the atmosphere to the surface of the Earth. Precipitation may reach the ground in the form of solid or liquid water including: rain, snow, sleet, or hail and even dew or fog. Temperature, pressure, and humidity affect the rate of precipitation. Temperature, pressure, and humidity affect the rate of precipitation.

FORMS OF PRECIPITATION Rain Snow Sleet Hail Precipitation may reach the ground in the form of solid or liquid water including: rain, snow, sleet, or hail and even dew or fog.

RAIN measured in millimeters using a RAIN GAUGE Precipitation in the form of falling liquid drops most common type of precipitation in our atmosphere Rain is precipitation in the form of falling liquid drops. Raindrops are by far the most common type of precipitation in our atmosphere. Rainfall is measured in millimeters using a rain gauge. Rain falls in showers or in drizzles. measured in millimeters using a RAIN GAUGE

SNOW Precipitation falling from clouds In the form of ice crystals Snow is precipitation falling from clouds in the form of ice crystals. The snow forms when water vapor turns into ice without passing through a liquid state. Snow is measured in inches with a ruler. Forms when water vapor turns into ice without passing through a liquid state Measured in inches with a RULER

Raindrops that freeze on Measured in inches with a RAIN GAUGE SLEET A mixture of rain and snow Raindrops that freeze on their way down to the Earth’s surface Sleet is a mixture of rain and snow or raindrops that freeze on their way down to the Earth’s surface. Unlike snow, the raindrops pass through a liquid form before freezing. Measured in inches with a RAIN GAUGE

Measured in inches with a RAIN GAUGE HAIL Precipitation in the form of spherically shaped pieces of ice larger than five millimeters in diameter Hail is precipitation in the form of spherically shaped pieces of ice larger than five millimeters in diameter. Hail and sleet are melted and measured using a rain gauge. Measured in inches with a RAIN GAUGE

CLOUDS A cloud is a collection of tiny water droplets or ice crystals floating in the atmosphere at varying altitudes. Cloud formations have both cooling and warming effects on Earth's surface dependent upon the altitude of the clouds in the atmosphere. Clouds occur at three ranges of altitudes in the sky. A collection of tiny water droplets or ice crystals floating in the atmosphere at varying altitudes

Found at high altitudes made CIRRUS CLOUDS Cirrus clouds are found at high altitudes made up of ice. Cirrus clouds are usually white and predict fair to good weather. The presence of cirrus clouds usually means a change in the weather will occur within 24 hours. Found at high altitudes made up of tiny ice crystals

White, puffy clouds that are referred to as "fair-weather clouds" CUMULUS CLOUDS Cumulus clouds are white, puffy clouds that are referred to as "fair-weather clouds". These clouds grow upward and they can develop into giant cumulonimbus clouds. White, puffy clouds that are referred to as "fair-weather clouds"

Uniform grayish clouds that often cover the entire sky. STRATUS CLOUDS Status clouds are uniform grayish clouds that often cover the entire sky. They resemble fog that doesn't reach the ground. Light mist or drizzle sometimes falls out of these clouds. Uniform grayish clouds that often cover the entire sky.

Thunderstorm clouds that are only found at low altitudes CUMULUS CLOUDS Cumulonimbus clouds are thunderstorm clouds and are only found at low altitudes. Thunderstorm clouds that are only found at low altitudes