5A-1 Gen Met and Sfc Wx Obs Flashcards by Andrew Timms

The stratosphere is characterized by

A temperature that remains isothermal to about 100,000 ft, the strongest concentration of ozone, and excellent flying conditions

How well did you know this?

Not at all

Perfectly

How many degrees centigrade does the temperature decrease per 1000 meters of altitude in the troposphere?

6.5

How well did you know this?

Not at all

Perfectly

Above 13 miles, the radiation from the sun breaks down the oxygen in the atmosphere into

Ozone gas

How well did you know this?

Not at all

Perfectly

Which statement best describes water vapor in the atmosphere?

The more water vapor, the lighter the air will be

How well did you know this?

Not at all

Perfectly

The two atmospheric gases most responsible for the absorption of incoming solar radiation are

Oxygen and ozone

How well did you know this?

Not at all

Perfectly

The driving mechanism that is mainly responsible for the earth’s large-scale atmospheric circulations is the

Unequal heating of the earth

How well did you know this?

Not at all

Perfectly

Which force is described as any center-seeking force?

Centripetal

How well did you know this?

Not at all

Perfectly

Which force is the “equal and opposite reaction” to the center-seeking force?

Centrifugal

How well did you know this?

Not at all

Perfectly

Centrifugal force (CeF) will increase when there is a decrease in

The radius of rotation

How well did you know this?

Not at all

Perfectly

Coriolis force (CoF) is created by

The cyclonic rotation of the earth

How well did you know this?

Not at all

Perfectly

If you throw a ball towards a stationary target from the window of a speeding vehicle, Coriolis force (CoF) will cause the ball to miss target

To the right

How well did you know this?

Not at all

Perfectly

The force that is responsible for starting the horizontal movement of air over earth’s surface

Pressure gradient

How well did you know this?

Not at all

Perfectly

The balance of forces needed for gradient cyclonic circulation is pressure gradient

Balanced against Coriolis and centrifugal forces

How well did you know this?

Not at all

Perfectly

The areas of low pressure that correspond to the belt of low pressure at 60 deg N created by the 3-cell circulation are the

Icelandic and Aleutian Lows

How well did you know this?

Not at all

Perfectly

In relation to the jet core, the greatest vertical wind shear is usually located

Above the jet core

How well did you know this?

Not at all

Perfectly

In relation to the jet core, the greatest horizontal wind shear is usually located

North of the jet core

How well did you know this?

Not at all

Perfectly

The simplest method for locating the 500 millibar frontal zone is to

Locate the position of the -17C isotherm

How well did you know this?

Not at all

Perfectly

The width of the jet stream core is approximately equal to the

Width of the 500 millibar isotherm ribbon

How well did you know this?

Not at all

Perfectly

Where are the greatest velocities located in relation to the subtropical jet (STJ)?

In the region of confluence of the STJ and polar front jet (PFJ)

How well did you know this?

Not at all

Perfectly

Jet fingers suggest

That the jet stream is beginning to dissipate

How well did you know this?

Not at all

Perfectly

Converging contours downstream of the jet stream will cause the jet to

Deflect toward lower heights

How well did you know this?

Not at all

Perfectly

Using average surface frontal slopes, how far ahead of the surface warm front is the jet stream located?

300 miles

How well did you know this?

Not at all

Perfectly

Which heat transfer process involves the transfer of energy by molecular motion from hot to cold objects?

Conduction

How well did you know this?

Not at all

Perfectly

Advection transfers temperature

Horizontally by the wind

How well did you know this?

Not at all

Perfectly

What factors must a region possess in order to facilitate air mass formation?

Uniform surface Stagnant air Large-scale difluent flow

Which process is most responsible for the slow formation of sir masses in the polar region?

Loss of heat by radiation

Air mass stability characteristics often depend on the temperature difference between the

Air mass and the surface over which it is traveling

How would you classify a stable air mass that formed over land in the Arctic has now moved over the ocean's warmer surface?

cAks

What air mass classification signifies an unstable, maritime tropical air mass that is colder than the surface it is moving over?

mTku

What air mass classification signifies a stable, continental polar air mass that is warmer than the surface it is moving over?

cPws

What air mass forms over land only during the summer?

As an air mass is heated from below, there will be increased

Instability and an increased lapse rate

It is winter. A cPk air mass is moving over the Great Lakes. In this situation, the southern shores of the Great Lakes will experience

Heavy snow

Which air mass involves most of the wintertime storms for the North American Pacific coast?

Continental tropical air masses are usually associated with

Thermal lows

The rate that an air mass modifies depends on the

Temperature differences between the new surface and the air mass, the nature of the surface over which it moves, and the speed with which the air mass travels

The weather characteristics of a particular month in a given locality are governed by

Effects of local topography and proximity to a zone of convergence

Surface pressure changes are largely controlled by

Mass changes in the upper troposphere

Horizontal divergence within an air mass will

Vertically contract the original column of air and then expand it horizontally

As air converges at the surface and toward the center of a layer, there will be horizontal

Contraction and vertical expansion

An increase of mass in a column of air will cause the surface pressure to

Increase

In the chimney effect, the maximum upward vertical wind motion will be located

At the level of nondivergence (LND)

The primary cause of surface pressure changes for a dynamic low is net

Divergence aloft

The damper effect is comprised of upper-level

Convergence and surface high pressure

A low-pressure system undergoing cyclogenesis is said to be

Forming or deepening

When the central pressure of an anticyclone is rising, you can infer the anticyclone is

Building

A high-pressure system undergoes anticyclolysis when the clockwise circulation area

Decreases or disappears

An unstable wave cyclone is one where the amplitude

Increases with time and the wave deepens

After warm air with an unstable wave is pushed aloft and cuts off from a cyclone, the cyclone will become

Barotropic and begin to fill

Unstable waves are classified as

Baroclinic lows

In the baroclinic instability process,

Potential energy is transferred to the major short wave by thermal advection

When using Petterssen's rule, the factors needed for cyclogenesis are upper-level

Divergence and a frontal zone where the thermal advection is weak

What causes the surface low to deepen during the self- development process?

Divergence aloft

A low dissipates after proceeding through it's entire life cycle which ranges from the

Bottom up as boundary layer convergence adds mass to the column of air

How many stages are there in the life cycle of a low?

Five

In the life cycle of a low, the system will evolve into a cold barotropic low in the

Dissipation stage

Anticyclogenesis typically occurs at, and just downstream from, long-wave

Ridges under confluent flow aloft

What causes a surface high to build during the self-development process?

Convergence aloft

Which is primarily responsible for low-level divergence acting as a braking mechanism for a high?

Friction

A warm barotropic high is a type of pressure system that

Has great vertical extent and is usually found over water areas

In regards to types of pressure systems, a heat low is a

Warm barotropic low that forms during the summer

With the passage of a cold front in the Northern Hemisphere, the horizontal wind direction will

Shift in a clockwise direction

The cold conveyor belt originates in the low levels that are located

East of a low center and flow westward

The average slope of a cold front is

1/30 to 1/100

A warm frontal occlusion occurs when the cool air

Behind the cold front overrides the colder air ahead of the warm front

In comparison to an active cold front, an inactive cold front is characterized by a relatively

Steeper slope, a narrow weather pattern, and is called katafront

When an inactive front passes your station, the dew points will

Decrease sharply with the passage

When only high and middle clouds are associated with a warm front, the

Overrunning warm air is dry

In a cold occlusion, the coldest air is found

Behind the cold front

In a cold occlusion, which type of front, if any, is found aloft?

The warm front

Frontogenesis requires two adjacent air masses with

Different densities and a wind flow to bring the air masses together

The frontolytic processes are most effective

In the lower layers of the atmosphere

The difference in cloud classification between L1 and L7 is

Precipitation

Which low cloud type and classification is identified by the presence of a cirriform anvil?

Cumulonimbus L9

The best way to distinguish stratocumulus from altocumulus clouds is to use

The size of the elements

A corona is often present at night with

Altocumulus clouds

Cirrus clouds in the form of an anvil are classified as

Which high cloud can occasionally be so transparent that the only indication of its presence is a halo phenomenon?

Which high cloud classification is also referred to as a mackerel sky?

Cirrocumulus-H9

Which orographic cloud resembles an almond or a fish?

Lenticular

Clouds or obscuring phenomena that have bases at the same approximate level is the definition of

A layer

What color ballon would you use to determine the ceiling heights of thin clouds?

Red

You are preparing to use a convective cloud height table to determine the heights of clouds. To do this properly, you must first determine the

Dew-point temperature and free-air temperature

How do you report prevailing visibility at US stations and overseas stations?

Statue miles for US stations and meters for overseas stations

To properly report the visibility for more than one sector, you wiped list the sectors in a

Clockwise direction starting with the northernmost sector

For a RVR report of R22/1000V1600FT, what is the visual range that a pilot can expect to see down the runway?

1,000 to 1,600 feet varying

What type of precipitation might you observe with clear skies?

Ice crystals

You would classify precipitation as intermittent if it

Stopped and started at least once within the preceding hour

When frozen precipitation is expected, you would

Collect it in the overflow unit of the rain gauge

The distinguishing feature of any tornadic activity is

The funnel-shaped appendage that hangs from the base of the cloud

A thunderstorm is present and occurring at your station. In addition, the local noise level is preventing you from hearing the thunderstorm. For observation purposes you would say

Hail is falling

A thunderstorm officially ends

Fifteen minutes after the last occurrence of thunder, hail, or lightning

For observing purposes, five hydrometers are considered to be obstructions to vision. They include mist, fog, blowing snow,

Freezing fog, and blowing spray

Blowing spray is reported only at sea stations near large bodies of water and when visibility at eye level is restricted to

9,000 meters or less

What pressure value is the basis for determining all other pressure values?

Station pressure

What is the reference level for all pressure values?

Sea-level pressure

The temperature to which a given parcel of air must be cooled, with constant water vapor content and pressure, to reach saturation is called

The wet-bulb temperature

The temperature an air parcel would have if it were cooled adiabatically to saturation at constant pressure by evaporation of water into it is called

Wet-bulb temperature

Wind observing equipment is oriented to

Magnetic north

A change in wind direction of 45 degrees (or more) that takes place in less than 15 minutes is

Wind shift