Weather Maps and Tools

Weather Maps and Tools

What are air masses?

Air Masses

• An air mass is a large body of air that has the same properties throughout.

• An air mass can be warm or cool, wet or dry.

Weather Fronts

a front is a boundary between two air masses.

There are 4 kinds of fronts: warm , cold, occluded, and stationary.

Weather often changes at fronts. The kind of weather that occurs at a front depends on how the air masses interact.

Warm Front

Warm Front - Forms when a warm air mass bumps into a cold air mass. The warm air slides up and over the cold air. This type of front typically brings light rain followed by warm, clear weather.

Cold Front

Cold Front - Occurs as a cold air mass pushes under a warm air mass. This type of front typically brings stormy weather, with cooler, clear weather following.

Stationary Front

Stationary Front - forms when a warm air mass and a cold air mass meet but neither is strong enough to move the other. This front typically brings light rain for several days.

Occluded Front

Occurs when a warm air mass is caught between two cold air masses.

Multiple Choice

A stationary front occurs when a warm air mass takes over a cold air mass and stays

• True

• False

Multiple Choice

An occluded front occurs when a warm air mass is caught between _____________.

• a warm air mass and a cold air mass

• 2 warm air masses

• 2 cold air masses

Multiple Choice

The weather was stormy for a short period of time, then became cooler. This was probably a warm front.

• True

• False

Air Pressure

• Air pressure depends on the density of the air.

• Air pressure decreases as you move higher through each layer of the atmosphere as there is less air above you to press down on you.

• Air moves from areas of high pressure to low pressure

Air Pressure Systems

Low-pressure systems form in areas where the air is slowly rising. The air also moves counterclockwise. This system brings cloudy skies and possibly rain or storms.

High-pressure systems form when the air in an area is slowly sinking. Clouds are likely to form and the air moves clockwise. This type of system usually means clear weather.

Multiple Choice

Air moves from areas of ___________ pressure to ___________ pressure

• low, high

• high, low

Multiple Choice

A ____________ pressure system brings stormy weather.

• High

• Low

• stationary

• occluded

Storms

• A storm is a type of system of severe weather that includes strong winds or large amounts of precipitation

Types of Storms

• Thunderstorms - small, intense weather systems that produce strong winds, lightning, thunder, and heavy rain.

• Occur inside warm, humid air masses and at fronts.

Types of Storms

• Tornados - rapidly whirling, funnel-shaped clouds that extend down from a storm cloud.

• Hurricanes - low-pressure tropical storm that forms over warm ocean water. Winds form a spinning pattern around the center, or eye, of the storm. The lower the air pressure at the center, the faster the winds move.

Weather Instruments

• Anemometers - measure wind speed

• Wind Vanes - show the direction of in which the wind is moving.

• Thermometers - measure temperature

• Barometers - measure air pressure

• Rain Gauges - measure the amount of rain fall

Measuring Relative Humidity

• Sling Psychrometer - measures relative humidity by using 2 thermometers and the cooling process of evaporation.

• Hydrometers - measure relative humidity by measuring the amount of moisture in the air.

Multiple Choice

_____________ measures air pressure.

• anemometer

• barometer

• thermometer

• wind vane

Multiple Choice

_____________ measures wind speed.

• anemometer

• barometer

• thermometer

• wind vane

Multiple Choice

__________________ shows the direction in which the wind is moving.

• wind vane

• barometer

• aneometer

• sling psychrometer

Detecting storms

• Radar - sends out radio signals that bounce off objects and returen to the instrument. Clouds, rain, and snow relfect the radar signals.

• Satellites - spacecraft that orbits Earth and gathers weather data based on cloud patterns and movement.

Weather Maps

• Isobars - connect areas of equal air pressure

• Isotherms - connect areas of eaual temperatures.

Showing fronts on a weather map

What type of weather would you expect to see in city C?

Enter your response in the following question.

Multiple Choice

What type of weather would you expect to see in city C?

• Rainy

• Snowy

• Clear and quiet

• Freezing

In what city would you expect to have stormy weather followed by cooler weather?

Enter your response in the following question.

Multiple Choice

In what city would you expect to have stormy weather followed by cooler weather?

• A

• B

• C

• None of the Above

In what city would you expect to steady rain for a few days

Enter your response in the following question.

Multiple Choice

In what city would you expect to have steady rain for a few days?

• A

• B

• C

• None of the Above

Convection Currents

• Convection currents are caused by the unequal heating of the Earth by the sun.

Climate Regions

There are 3 distinct regions caused by atmospheric convection.

Tropical, Temperate, and Polar

Tropical Climates

Close to the equator

This climate zone experiences high temperatures all year round and lots and lots of rain.

Temperate Climates

Does not have extremes. While the polar climate is extremely cold and the tropical climate is very hot, the temperate climate has some hot weather and some cold weather. While there is a lot of rain and snow in other zones, the temperate zone has just a moderate amount of rain and snow.

Polar Climates

closer to the poles.

Polar climates are almost always covered with snow and have extremely cold temperatures. The temperature rarely rises above the freezing point

Multiple Choice

The Earth is divided into ____________ distinct climate regions.

• 2

• 3

• 4

• 5

Multiple Choice

Climate Regions are caused by __________________ in the Earth's atmosphere.

• conduction

• Radiation

• Convection

Multiple Choice

Convection currents are caused by _______________.

• season changes

• latitude

• equal heating of the earth by the sun

• unequal heating of the earth by the sun

Global Winds

• Occur in each of the climate regions and affect the direction of weather systems on Earth.

Trade Winds and Westerlies

• Trade winds and Westerlies affect the direction of tropical weather systems (hurricanes

Trade Winds and Westerlies

• Trade Winds occur in tropical climates and move in from the east.

• Prevailing Westerlies occur in temperate climates and move toward the west

• Polar Easterlies occur in polar climates and move toward the east.

Jet Streams

• Fast moving ribbons of air that move from west to east in the northern hemisphere.

• The polar jet stream brings down cold polar conditions from the north.

Multiple Choice

Fast moving ribbons of air that move from west to east in the northern hemisphere are called ________________________.

• Global Winds

• Convection Currents

• Jet Streams

• Ocean Currents

Multiple Choice

________________________ occur in temperate climates and move toward the west.

• Easterlies

• Westerlies

• polar jet stream

• Trade Winds

Multiple Choice

________________________ occur in tropical climates and move in from the east.

• Easterlies

• Westerlies

• polar jet stream

• Trade Winds

Multiple Choice

________________________ occur in polar climates and move toward the east.

• Easterlies

• Westerlies

• polar jet stream

• Trade Winds

Jet Streams

• Polar Jet stream moves from west to east

• Subtropical Jet stream moves west to east near the equator

Ocean currents

• circulate warm and cold water in convection patterns and influence the weather and climates of the land masses nearby.