Science Chapter 20

What is the difference between a snowstorm and a blizzard? (20.4)

A blizzard includes both heavy snow PLUS heavy winds of greater than 56 kilometers/hour -- so the main difference is the winds. Also the definition of a blizzard requires a temperature of less than -7 Celcius.

Occluded Front

A cold air mass is generally faster than a warm air mass and a occluded front occurs when the cold air mass catches up to the warm air mass, the warm air is forced to rise and as the air rises, the temperature cools causing condensation to occur.

What would have just happened if a squall line of thunderstorms passed overhead followed by clear, cool conditions? (Made up)

A cold front would have just come through

What type of weather occurs after an occluded front? (Made up)

Can bring strong winds and heavy precipitation

How do you interpret a station model? (Made up)

Circle= location Shading inside circle= cloud coverage' Staff=wind direction Flags= wind speed

Weather associated with a high pressure system? (Made up)

Clear skies, cold temperature, clockwise spin outwards. (This is true until high pressure system meets up with low pressure system, causing warmer, low-pressure air to rise and create precipitation)

Describe maritime polar air and where it originates from (20.1)

Cold & Damp/Moist (Not as cold as continental polar air) Maritime Polar - originates over ocean in high latitudes -- RESPONSIBLE FOR NOR'EASTERS

Describe continental polar air and where it originates from (20.1)

Cold & Dry Continental Polar- originates inland over regions of Alaska and Canada

Explain how cold air masses originate (20.1)

Cold air masses originate over areas of the earth that are colder due to lack of sun

What are the four major types of fronts? (Made up)

Cold, warm, stationary, occluded.

What are the names of the air mass source regions? (Made up)

Continental Arctic; cA Continental Polar; cP Continental Tropical; cT Maritime Polar; mP Maritime Tropical; mT

Explain how continental polar air can bring clear weather to one region while causing heavy snow in another (20.1)

Continental polar air originates over cold land masses, and is dry and cold. But when it crosses water, like when Canadian dry air passes south over the US great lakes, it picks up moisture and then dump snow. ALSO -- polar air can hit a mountain and move up and cause precipitation.

What are the major air masses that influence the weather in the US? (Made up)

Continental polar, maritime polar, continental tropical, maritime tropical

Why are so many station models used to gather weather data in the U.S.? (Made up)

The U.S. is very large, a large number of station models help give a more complete picture of weather and make weather forecasts more accurate.

How can a range of mountains influence the weather and what is that called?

The air rises and cools, clouds will form precipitation will form on the windward side; it is called orographic lifting

An occluded front forms when a __________ air mass is trapped between two __________ air masses and loses contact with the _________.

warm; cold; ground

An occluded front forms when a __________ air mass is trapped between two __________ air masses and loses contact with the _________. (Made up)

warm; cold; ground

Describe how a hurricane forms (20.4)

-Hot air begins to rise. -As it rises, it cools and condenses, releasing heat. -As inside part of cloud gets warmer and keeps rising, more and more moist, warm air is sucked up from the surface of the ocean -Cooler air on the outside of the cloud starts to rotate with the coriolis effect until a swirling pattern emerges

List the 5 principal North American air masses and where they originate from (20.1)

1. Continental Arctic - originates near the poles 2. Continental Polar- originates inland over regions of Alaska and Canada 3. Continental Tropical - originates over deserts of southwest and Mexico; causes heat waves in southern US 4. Maritime Polar - originates over ocean in high latitudes -- RESPONSIBLE FOR NOR'EASTERS 5. Maritime Tropical - Originates over tropical oceans - BRINGS HEAT AND HUMIDITY TO MIDWEST AND EASTERN US (SUMMER THUNDERSTORMS)

Describe three ways of gathering weather data for forecasts. (20.5)

1. Satellites: 2 types of satellite images: Visible images; only available in daytime Infrared images: rely on temperature; Both measure wind speeds, but infrared can also measure temp. 2. Radiosondes: A radio package tied to a balloon. Measures temp, pressure and humidity. Sends info back in the form of radiowaves to computers. Can help determine how unstable air is at dif altitudes. 3. Surface Observations: Weather stations at airports, ocean buoys, Tracks dew points, air pressure and wind speed.

Explain the 2 types of satellite images. (20.5)

2 Types of Satellite IMages you could get: Visible images; only available in daytime Infrared images: rely on temperature Both measure wind speeds and cloud position. Infrared also measures temp.

Which correctly compares low and high pressure weather systems? (Made up)

A low pressure system usually brings clouds and precipitation, while a high pressure system brings cool dry air and clear skies.

What is a mid-latitude Cyclone? How does it form? Where does it form? What type of weather does it bring? (Made up) -- Associated concept is the occluded front.

A mid-latitude cyclone starts off as a low pressure ripple on a stationary polar front where cold polar air meets warm tropical air, brings snow precipitation. As the central pressure drops, warm tropical air on the east moves northward and cold polar air from the west moves southward, quicker moving cold front catches up with warm, causes occluded front, eventually looses energy and weakens

What is a radiosonde and what can it tell you?

A radio package tied to a balloon. Measures temp, pressure and humidity. Sends info back in the form of radiowaves to computers. Can help determine how unstable air is at dif altitudes.

What is a station model? (Made up)

A symbolic representation of data from a weather station on a weather map; each number and symbol, and their locations in the model, provide specific provide specific weather information

What is this a definition of? A storm produced by a cumulonimbus cloud and always accompanied by lightning and thunder, relatively short in duration and usually has strong gusts of wind, heavy rain, and sometimes hail. (Made up)

A thunderstorm

What type of weather does a warm front bring?

As the warm air mass rises, it condenses into a broad area of clouds. A warm front brings gentle rain or light snow

What causes dew? (Made up)

At night and in the early morning, the air cools and it can hold less moisture. Dew is water that condenses from the air in the early morning.

Explain what causes lightning. (Made up)

An atmospheric electrical discharge that occurs either between clouds or between a cloud and the ground. Top part of cloud has positive charge; bottom part of cloud has negative charge.

What is this a definition of? A front formed when a cold front overtakes a warm front , marking the beginning of the end of a mid-latitude cyclone (Made up)

An occluded front

Explain how upper air flow can cause a high to strengthen

As cold air sinks it eventually its the earth's surface, which slows down the sinking air (gets squished). At the same time warm air is rising. If more air enters downward (cold air) than is flowing upward (hot air) the high will strengthen.

What is a front? (20.2)

Boundary that separates opposing air masses. Note -- air masses DON'T easily mix

What type of weather does a high pressure system bring? (Made up)

Brings fair weather and light winds; sunny skies Happy Weather! However, should this front collide with a low-pressure front, condensation/precipitation will occur.

On a weather map, a large H appears over an area in which you live. What kind of weather can you expect? (Made up)

Dry and clear

How do fronts cause weather changes? (Made up)

Fronts and boundaries between air masses. When a front occurs, air mass of different temperatures and humidity interact. The interactions of air masses cause weather changes.

What should you do if a tornado is approaching? (20.3)

Go to a basement or storm cellar. Stay away from windows and outside walls. If caught outside, lie in a ditch or low-lying area.

Explain why heavy rain accompanies a hurricane. (20.4)

Heavy rain accompanies a hurricane because hurricanes form over warm oceans. As hot air rises over the warm moist ocean, it condenses and causes precipitation.

Which is associated with cold air -- high pressure or low pressure?

High Pressure. Molecules in cold air are closer together and are therefore heavier. - or "high pressure." Barometric pressure will measure the force of the area as it pushes down onto the earth.

Explain how hot air masses originate (20.1)

Hot air masses originate over areas of the earth that are warmer due to direct sun heating the earth.

How does a nor'easter form? (Made up)

Is a macro-scale cyclone. Typically, such storms originate as a low-pressure area; They thrive on converging air masses—the cold polar air mass and the warmer air over the water—and are more severe in winter when the difference in temperature between these air masses is greater

A low is predicted to pass through Florida in the winter. Do you forecast warm or cold temperatures for Georgia? Why? (20.2)

It will be first warm, then get cold. First the warm low-pressure front will continue to move north through Florida and into Georgia, making it warmer. Then it will run into a cold front, causing the warm air to rise and precipitation to then occur -- in turn cooling things down.

Which will be the effect of a warm front moving into an area? (made up)

Light precipitation will begin as the front arrives and clear after the front is gone.

________________ systems are the main reason for Nor'easterns forming.

Low

Which is associated with warm air - high pressure or low pressure?

Low Pressure. Molecules in warm air are already further apart and so the air is lighter or "low pressure."

What type of weather would you expect an occluded front to produce? (Made up)

Much precipitation

Can thunder occur without lightning? (20.3)

No because the noise is caused by lightening strike itself.

What is a mesocyclone? (20.3)

Often turns into a tornado if it touches the ground, a mesocyclone is a rotating updraft within a thunderstorm. Occurs when a low altitude winds are blowing at a different speed or direction that winds higher up.

Describe some positive and negative ways in which hurricanes may affect plants.

Positive: Can bring lots of water and soak the earth in a hot climate. Negative: Can bend/break plants or causes flooding (too much water)

What kind of weather is associated with a stationary front? (Made up)

Probably cloudy and rainy as long as the front lies over an area. After the front passes, the weather will usually clear up.

Are temperatures usually higher to the east or the west of the low pressure system? How do these temperature s relate to the wind that is swirling into that low? (made up)

The east because the low pressure system (hot air) is swirling from west towards the east. Air from the north is flowing from west to east as well, cooling air on the western part of the warm front. The low strengthens because of the upper air flow , if more air rises out of s surface low than spiral into it on the ground, the low strengthens.

Why do thunderstorms form along fronts? (Made up)

The frontal boundary forces air to rise , associated with large scale low pressure systems and may stop and start for days, thunderstorms can occur ahead of the front called squall lines, strong winds and heavy rains follow

What information can you get from a weather map? (Made up)

The location and types of fronts, areas of low and high pressure and predictions of weather for certain areas.

If an observer in the Northern Hemisphere sees snow falling heavily with winds from the northeast, where is the low-pressure system relative to the observer? (20.2)

The low-pressure system would be southwest of me.

What type of weather does an occluded front bring? (Made up)

The temperature drops as the warm air mass is occluded, or "cut off," from the ground and pushed upward

The local weather station is predicting that a warm front will pass through Charlotte, NC in two days. How will Charlotte's weather most likely be affected by the passing of a warm front? (made up)

The temperature will increase.

What is weather associated with cumulonimbus clouds? (Made up)

Thunderstorms, tornados and lightening

Describe continental arctic air and where it originates from (20.1)

VERY Cold & Dry Continental Arctic - originates near the poles

Describe continental tropical air and where it originates from (20.1)

VERY Hot & Dry Continental Tropical - originates over deserts in Southwest and Mexico; causes heat waves in southern US

Describe maritime tropical air and where it originates from (20.1)

Warm & Moist Maritime Tropical - Originates over tropical oceans - BRINGS HEAT AND HUMIDITY TO MIDWEST AND EASTERN US (SUMMER THUNDERSTORMS)

What Conditions are necessary for the formation of a thunderstorm? (20.3)

Warm, moist, unstable air. Often occur during the afternoon because surface warming throughout the day causes the air to become unstable; then a trigger happens that causes the air to rise abruptly.

What are the differences between warm and cold air masses? (Made up)

Warm= warmer than ground, lower atmospheric pressure, brings warm air, and has a higher dew point Cold= cooler than ground, higher atmospheric pressure, brings cold air, and has a lower dew point

Describe the weather conditions associated with warm fronts

Weather change more gradual as warm air moves upward slowly (low pressure air). The denser cold air retreats slowly. Warm air rises much more slowly creating larger areas of cloud cover over time and drizzly precipitation.

What direction do Global Winds blow over the United States?

West to East (prevailing westerlies)

Describe the weather conditions associated with cold fronts-- i.e., when they move south and hit a warm front.

When dry cold air moves from north to south (high pressure air running into low pressure air) hot HUMID air is thrust up quickly, causing heavy and quick-forming thunderstorms. The exception is if the cold air displaces really hot DRY air; in which case you will get only wind.

How does latent heat released during condensation cause air in a cloud to sometimes grow into thunderstorms and hurricanes?

When the water vapor condenses to form clouds and precipitation, it releases latent heat into the atmosphere The latent heat warms the air and creates instability , increases cloud height and thunderstorms could form.

Explain how tornadoes form. (Made up)

When wind traveling in two different directions causes the air in the middle to rotate. The rotating column of air is turned upright by updrafts that begin spinning with it. The rotating air works its way down to the bottom of the cloud and forms a funnel cloud. When the funnel cloud touches the ground, it is called a tornado.

What type of weather does a stationary front bring? (Made up)

Where the warm and cold air meet, clouds and fog form, and it may rain or snow over many days.

Define cold front (Made up)

a front along which a cold air mass thrusts beneath a warmer air mass

Define warm front (Made up)

a front along which a warm air mass overrides a retreating mass of cooler air

Define occluded front (Made up)

a front formed when a cold front overtakes a warm front , marking the beginning of the end of a mid-latitude cyclone Also when a warm air mass is trapped between 2 cold air masses.

Define air mass (Made up)

a large body of air that is characterized by similar temperatures and amounts of moisture at any given altitude

Define stationary front (Made up)

a situation in which the surface position of a front does not move; the flow on either side of such a boundary is nearly parallel to the position of the front

How can you recognize different air source regions? (Made up)

cA= dry and frigid cP= dry and cold cT= dry and warm mP= humid and cold mT= humid and warm

What two things can form when air is lifted? (Made up)

clouds and precipitation

Which winds are most responsible for the cold weather that occurs in North Carolina during the winter? (Made up)

continental polar

Which is most responsible for guiding the movement of different air masses across the United States? (made up)

jet stream

As a high pressure system moves closer to Massachusetts, from which direction will the winds most likely begin to blow? (made up)

from the north

What would air masses moving over Hawaii probably identified as?

maritime tropical (mT)

what air masses are involved with a midlatitude cyclone?

maritime tropical and continental polar, two meet in the middle and KABLOOM

When a cold front "catches up" to a warm front, the result is a _______________________________________?

mid-latitude cyclone

Which type of weather is most often produced by a low air pressure system? (Made up)

rainy

Which best explains why weather across the United States continually changes? (made up)

the movement of high and low air pressure masses