MET1010 Exam 3

The smallest scale of atmospheric motion is the

Microscale

Which of the following associations is most accurate?

Synoptic Scale- Lightning

A hurricane or tropical storm would fit under which scale of motion?

Synoptic

The nighttime reversal of the sea breeze circulation is called a

Land Breeze

A valley breeze would be strongest

In the Late Afternoon

A katabatic wind is a _, _ wind.

cold, downslope

Chinook winds are

hot, dry, downslope winds

The intertropical convergence zone (ITCZ) is a region where

Northeast trades meet the southeast trades.

In the three-cell model of the general circulation, areas of surface low pressure should be found at

The equator and 60 latitude

The winds located in the tropics in the Northern Hemisphere are the

Northeast tradewinds

The name of the large convection cell that is located in the tropics is

Hadley Cell

The pressure systems found at 30 latitude are called

Subtropical highs

In terms of the three-cell general circulation model, the driest and most stable regions of the Earth should be near

30 Latitude and the polar regions

Which of the following does not describe the subtropical jet stream?

Forms along 60 N latitude

If the trough of the polar jet stream were to push as far south as Central Florida

the Northern half of Florida would be cold

The polar jet stream moves faster and farther south in the

Winter

The name given to the current of warm water that replaces cold surface water along the coast of Peru and Equador during December is

El Nino

Which of the following would not be associated with a major El Nino event?

Higher than normal numbers of hurricanes and tropical storms in the Atlantic

The reversal of positions of surface high or low pressure at opposite ends of the Pacific Ocean is called

The Southern Oscillation

A good source region for an air mass would be

generally flat areas of uniform composition with light surface winds

Which air mass forms over North America only in winter?

cA

An air massis characterized by similar properties of _ and _ in any horizontal direction

Temperature, moisture

The air mass responsible for droughts in the southwestern US is

cT

What type of air mass would be responsible for daily afternoon thunderstorms along the Gulf Coast

mT

An mP air mass is more _ in the winter and more _ in the summer.

Unstable, Stable

Lake effect snow occurs in the winter when _ air mass moves over a _ body of water.

a cP, warm.

When two air masses collide at a front, one air mass is pushed upward by the other. This is because

One air mass is denser than the other

Occluded fronts may form as

a cold front overtakes a warm front

The rising of warm air up and over cold air is called

Overrunning

Before the passage of a cold front the pressure normally _, and after the passage of a cold front the pressure normally _.

Drops, Rises

What type of weather front would be responsible for the following: "Increasing high cloudiness and cold this morning... Turning much warmer. Winds light easterly today become southeasterly tonight and southerly tomorrow."

warm front

What type of weather would be responsible for the following: "Warm and humid today with thunderstorms likely. Decreasing clouds tomorrow with winds becoming northwesterly and tuning much colder."

Cold Front

When comparing and "average" cold front to an "average" warm front, which of the following is not correct?

Generally, precipitation covers a much broader area with a cold front.

A stationary front does not move because

the winds blow parallel to the front.

A mid-latitude cyclone or wove cyclone is normally most intense

When the system first becomes occluded

The development or strengthening of a middle latitude storm system is called

Cyclogenesis

Tornado watches would be issued by

SPC or NSSFC

The most accurate local weather forecast would be issued by

WFO

A hurricane warning would be issued by which of the following offices?

NHC

A tornado warning would be issued by which of the following offices?

WFO

Which of the following offices is responsible for naming storms?

WMO

CHAPTER 7: ATMOSPHERIC CIRCULATION

Atmospheric motion, local winds, global circulation, pressure belts, jet streams, ocean circulation, and ENSO.

Macroscale / Planetary Scale

Largest atmospheric-motion scale; lasts months–years and spans about 3,000–24,000 miles.

Macroscale Examples

El Niño, jet streams, and trade winds.

Synoptic Scale

Weather-system scale lasting days–weeks and spanning about 100–1,000 miles.

Synoptic Scale Examples

Fronts, high/low pressure systems, and hurricanes.

Mesoscale

Local atmospheric motions lasting minutes–hours and spanning about 0.5–100 miles.

Mesoscale Examples

Thunderstorms, tornadoes, waterspouts, and sea breezes.

Microscale

Smallest atmospheric-motion scale; lasts seconds–minutes and spans less than about 0.5 mile.

Microscale Examples

Lightning, downbursts, turbulence, and dust devils.

Cause of Wind

Pressure differences caused by temperature differences from unequal heating of Earth.

Sea Breeze

Daytime local wind that blows from water toward land.

Strongest Sea Breeze

Usually occurs during late afternoon, especially in summer.

Land Breeze

Nighttime local wind that blows from land toward water.

Valley Breeze

Daytime/afternoon flow from a valley toward or up mountain slopes.

Mountain Breeze

Nighttime flow from a mountain toward the valley.

Chinook

Warm, dry downslope wind on the eastern side of the Rocky Mountains.

Foehn

Warm, dry downslope wind associated with the Alps.

Santa Ana Wind

Hot, dry downslope wind.

Katabatic Wind

Cold, dense air flowing downhill under the influence of gravity.

Country Breeze

Local wind from cooler countryside toward a warmer urban area.

Three-Cell Circulation Model

Each hemisphere contains Hadley, Ferrel, and Polar circulation cells.

Hadley Cell

Circulation cell extending approximately 0°–30° latitude.

Ferrel Cell

Circulation cell extending approximately 30°–60° latitude.

Polar Cell

Circulation cell extending approximately 60°–90° latitude.

0° Pressure Belt

Equatorial Low.

30° Pressure Belt

Subtropical High.

60° Pressure Belt

Subpolar Low.

90° Pressure Belt

Polar High.

Pressure Belt Pattern

0° LOW → 30° HIGH → 60° LOW → 90° HIGH.

Equatorial Low

Low-pressure region around 0° with rising air and wet, unstable conditions.

ITCZ

Intertropical Convergence Zone near the equator where trade winds converge.

Doldrums

Equatorial region of hot, humid conditions and generally light winds.

Subtropical High

High-pressure belt around 30° with sinking air and dry, stable conditions.

Horse Latitudes

Calm subtropical region around 20°–35° associated with sinking air and high pressure.

Subpolar Low

Low-pressure region around 60° associated with rising air and wet, unstable conditions.

Polar Front

Region near 60° where cold polar easterlies meet warmer prevailing westerlies.

Polar High

High-pressure region around 90° characterized by sinking, dry, stable air.

Trade Winds

Major wind belt from approximately 0°–30° latitude.

Prevailing Westerlies

Major wind belt from approximately 30°–60° latitude.

Polar Easterlies

Major wind belt from approximately 60°–90° latitude.

High Pressure Weather

Sinking air, surface divergence, dry/stable conditions, and generally clearer weather.

Low Pressure Weather

Rising air, surface convergence, wet/cloudy conditions, and greater instability.

Siberian High

Semipermanent high-pressure center important during winter.

Aleutian Low

Semipermanent low-pressure center important during winter.

Icelandic Low

Semipermanent low-pressure center important during winter.

Bermuda High

Important subtropical high-pressure center, especially during summer.

Azores High

Subtropical high-pressure center over the Atlantic.

Monsoon

Seasonal reversal in wind direction.

North American / Southwest Monsoon

Dry spring followed by increased summer rainfall in the southwestern U.S.

Jet Stream

Narrow ribbon of very fast-moving air high in the atmosphere that helps steer weather systems.

Polar Jet

Jet stream around 30,000 ft associated with cold air advection and weather-system steering.

Subtropical Jet

Jet stream around 40,000 ft associated with warm air advection and weather-system steering.

Jet Stream Memory Trick

Polar = 30,000 ft/cold; Subtropical = 40,000 ft/warm.

Rossby Waves

Large waves or bends in the upper-level westerlies/jet stream.

Flatter Rossby-Wave Flow

Generally associated with less cyclone activity.

Large-Amplitude Rossby Waves

Associated with more vigorous cyclone activity.

Northern Hemisphere Ocean Gyres

Generally rotate clockwise.

Southern Hemisphere Ocean Gyres

Generally rotate counterclockwise.

Cold Ocean Currents

Can contribute to fog and dry coastal climates/deserts.