Main One: Meteorology 1050 Exam 3

To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for

Altitude

The contour lines drawn on a 500 mb chart are lines of constant

Pressure

Lines connecting points of equal pressure are called

Isobars

A rapid change in pressure over a relatively short distance is called a ___ pressure gradient

Steep

If you live in the Northern Hemisphere and a region of surface low pressure is directly west of you, the surface wind direction at your home would probably be either

South or southwest

The wind around a surface high pressure center in the NH blows

Clockwise and outward from the center

Where is the effect of the Coriolis force greatest?

At the poles

A geostrophic wind is a wind that results from the balance between the ___ force and the ___ force

Coriolis, pressure gradient

Upper-level winds in the middle latitudes of both hemispheres generally blow from the

west

Wind direction is

The direction from which the wind is blowing

T/F A valley breeze develops its maximum strength in the early afternoon

True

T/F Sand ripples can indicate the prevailing wind direction in an area

True

T/F Strong winds blowing over vegetation can result in rapid water loss

True

​Suppose a west wind of 20 knots blows over a coastal region which is densely covered in shrubs. If this same wind moves out over the middle of a large calm lake, its speed and direction would probably be

Stronger than 20 knots and more northwesterly

Chinook winds

Warm, dry downslope winds

What is a serious hazard to aircraft?

Clear-air turbulence

During a major El Nino event ___

Extensive ocean warming occurs over the tropical pacific

A condition where the central and eastern tropical pacific turns cooler is called

La Nina

Flowing north along the east coast of the US is a tremendous warm current called the

Gulf Stream

​On a surface weather map during the month of July, one would expect to find what type of pressure system over the desert southwest of the United States?

Thermal low

Jet streams can form near Earth's surface as well. One such jet develops just above the central plains of the United States, where it occasionally attains speeds exceeding 60 knots. This wind speed maximum, which usually flows from the south or southwest, is known as a(n) ____________________ jet.

Low level

Due to Hadley Cell formation and the Coriolis force in both hemispheres, winds aloft flow

Westerly

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

El Nino

In the NH air found to the north of the polar front is ___ while air further south is ___

Cold, warm

Forms near the boundary called the polar front

Polar front jet stream

T/F Drylines are most frequently observed in the western half of Texas, Oklahoma, and Kansas, especially during spring and early summer. In these locations, drylines tend to move eastward during the day, then westward toward evening.

True

A cold front that moves into New England from the Atlantic Ocean

Back door cold front

T/F In the central plains, continental polar air is common in winter and summer

False

Alternating lines of blue and red on a weather map indicate

Stationary Front

The coldest of all air masses

cA

Which air masses are formed in regions where long, clear nights allow for strong radiational cooling of the surface?

cP and cA

Greatest contrast in temperature and moisture will occur along the boundary separating which two air masses?

mT and cP

Before the passage of a cold front the pressure normally ___ and after the passage of a cold front the pressure normally ___

drops, rises

The formation, strengthening or regeneration of a front (increase temp difference)

Frontogenesis

The weakening or dissipation of a front

Frontolysis

A transition zone between air of different densities, and a boundary between air masses with different characteristics

Weather Front

Advancement of warm air

Red ovals point in the direction warm air is moving

Light rain along front

Warm Front

Advancement of cold air

Blue triangles point in the direction the cold air is moving

Active weather along front

Cold Front

No movement along front

Big differences in air masses, north and south in front

Drawn in alternating red and blue colors

Stationary Front

Warm and cold fronts collide

Attached to strong low pressure systems

Drawn in alternating purple pips

Occluded Front

Line separating dry air from moist air

Warm dry air moves over warm moist air

Drawn in yellow tight pips

Dryline

Air mass with with low temps and dry air

Continental Polar (cP)

Air mass with extremely low temps and very dry air

Continental Arctic (cA)

Air mass with high temp and low humidity

Lacks moisture, ensures dry weather

Continental Tropical (cT)

Air mass with low temps and high humidity

Maritime Polar (mP)

Air mass with high temps and humidity

Maritime Tropical (mT)

Causes heavy rain and mudslides in Cali (Seth Rogan Movie)

Pineapple Express

Narrow Air currents found around 36,000 ft.

Form at boundaries of adjacent air masses with significant differences in temp, moisture, and pressure

Separate warm air from cold air

Jet Stream

North of the jet stream temps are ___

Colder

South of the jet stream temps are ___

Warmer

Arctic jet (northern) which affects us in winter

Polar Jet stream

Warmer air (southern) brings in moisture and affects us in spring and summer

Subtropical Jet stream

Forms over the central plains

Causes nighttime t-storms

Close to surface

Low-Level Jet

Where is the jet stream located?

Just below the tropopause

Clockwise wind flow, fair and calm weather

High Pressure

Counter-clockwise wind flow, unsettled and stormy weather

Low Pressure

Long term average of wind over the globe

General circulation of the atmosphere

Idealized model that transports heat from the equator to the polls

Cannot happen due to Coriolis Force

Single-Cell Model

Idealized triple-cell model that transports heat and energy distribution across different parts of the hemisphere

Due to Earth's rotation and Coriolis Force we have

Triple-Cell Model

Surface winds move from north to south and are turned right by Coriolis

Northeast trade winds

Located at Equator

Hadley Cell

Surface winds move south to north and turn right

Westerlies

Located at mid-latitudes

Ferrell Cell

Surface winds move north to south and turn right

Polar easterlies

Located at the poles

Polar Cell

Area where northeast and southeast trade winds come together

Low pressure and converging air

Intertropical Convergence Zone

Low pressure over eastern pacific, high pressure over western pacific (warm water)

El Nino

Low pressure over western pacific, high pressure over eastern pacific (cool water)

La Nina

Breeze blowing from land to the sea, due to relative warmth of land

Sea Breeze

Breeze blowing from the sea to the land due to warmth of ocean

Land Breeze

Spinning vortices seen on hot, dry days

Dust devils

Wind from the ocean that carries moisture (June in South Asia)

Wet monsoon

Dry wind from dry land (October to May in South Asia)

Dry monsoon

Spins on a post until the arrow points into the wind

Wind Vane

Points into the wind to give direction and a propeller spins to give speed

Aerovane

Cups on a pole spin faster in a strong wind

Anemometer

A vertical pointing radar that can tell how wind changes with height

Wind Profiler

Instrument tied to the bottom of a weather balloon

Transmit temp, pressure and relative humidity

Radiosonde

Weeks to seasons

4,000-40,000 km.

Westerlies, trade winds, longwaves

Planetary Scale of Motion

Large Scale

Days to weeks

The entire U.S

Hurricanes, Fronts, Cyclones

Synoptic Scale of Motion

Middle Scale

Minutes to hours

Sea Breeze, Mountain Breeze, Severe Weather

Mesoscale

Smallest scale

Seconds to minutes

Local winds, tornadoes and eddies

Microscale

Lowest part of the atmosphere from ground to cumulus cloud formation

Planetary Boundary Layer

Horizontal difference in pressure

Closer isobars mean larger pressure change over short distance

High to lower pressure

Pressure Gradient Force (PGF)

Apparent force created by rotation of the Earth

Wind deflects right in the NH

Wind deflects left in the SH

Strongest at poles, weakest at Equator

Coriolis Force

Why does wind speed increase with height above surface?

Friction with surface slows air near the ground

What does cyclonic flow in NH mean?

Counterclockwise flow

Warm, dry wind from southern California

Santa Anna wind

Expect air to ___ above surface low pressure and ___ above surface with high pressure

Rise, sink

What are ridges on a weather map?

Elongated high pressure areas

What causes sea or land breezes?

Temp difference

Large thermally convection cell that is driven by "hot" towers along the Equator is the

Hadley cell

According to three-cell general circulation model we would not expect to find ___ at the Equator

Ridges of high pressure

Which way does the jet stream flow?

West to East

What is the Low-Level Jet Stream over the central plains responsible for?

Nighttime T-Storms

One would expect a cP air mass to be

Cold and dry

Record breaking low temps are associated with

cP

Warm moist air mass forms over water

mT

Air mass responsible for daily afternoon T-Storms along Gulf Coast

mT

Front drawn in blue represents where cold air replaces warm

Cold-type occluded front

Generally flat area of uniform composition with strong surface winds

Good source region for air mass

Compared to an mP air mass, mT air is

Warmer and moister

What kind of air mass does the pineapple express originate from?

Maritime Tropical