Weather Test

The large thermally driven convection cell that is created by towering cumulus clouds along the equator is the

Hadley cell

The intertropical convergence zone (ITCZ) is a region where

Northeast and southeast trade winds converge, causing rising air and thunderstorms(convergence of winds)

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

0° (equator) and 60° latitude

The majority of the United States lies within which wind belt?

Westerlies

The world’s deserts are found at 30° latitude because:

Air descends there, creating dry, high-pressure zones

What causes the downdraft in the mature stage of a single-cell thunderstorm

cool, dense air descending, produced by evaporative cooling and drag from falling precipitation (rain/hail).

Which of the following is considered to be a boundary between two different air masses?

Front

The greatest contrast in both temperature and moisture will occur along the boundary separating which air masses?

Continental polar (cP) and maritime tropical (mT)

What can happen when gust fronts from multiple thunderstorms merge?

forming multicell clusters, squall lines, or enhancing outflow boundaries that intensify convection.

What type of air mass would be responsible for hot, muggy summer weather in the Midwest United States?

Maritime tropical (mT)

What type of air mass would be responsible for persistent cold, damp weather with drizzle along the east coast of North America?

Maritime polar (mP)

f an observer sees cirrus clouds, followed later by cirrostratus, and then altostratus, he or she is witnessing the approach of a ________ front.

Warm front

A wind shift from south or southwest to northwest is commonly associated with the passage of a ________ front.

Cold front

When an active cold front overtakes a warm front ________.

An occluded front forms

Along the boundary between cP and mT air masses, ________ is often found.

A front or dry line

Which of the following is NOT a condition under which air mass wind shear occurs

Uniform, unchanging wind profiles with no directional or speed change

Low level wind shear tends to _____ a warm frontal passage and _____ a cold frontal passage.

Increase; then decrease

The main difference between a downburst and a microburst is:

A microburst is smaller (<4 km), short-lived, but more intense than a downburst

Turbulence within thunderstorms is most intense

Near updrafts and downdrafts, especially in the mature stage

The magnitude of turbulence depends on:

Wind shear and the strength of vertical motions- updraft and down drafts

Low level turbulence includes

Mechanical, convective, and wake turbulence

What type of weather front would be responsible for the following weather forecast? "Increasing high cloudiness and cold this morning. Clouds increasing and lowering this afternoon with a chance of snow or rain tonight. Precipitation ending tomorrow morning. Turning much warmer. Winds light easterly today becoming southeasterly tonight and southwesterly tomorrow."

Warm front

Relief from thermal turbulence can be found above:

The temperature inversion

A small thunderstorm cloud with virga falling out of its base and blowing dust at the ground could warn of severe hazard to an airplane because:

Strong downdrafts or microbursts

Which fog forms when warm, moist air moves horizontally over a colder surface like cold ground or water

Advection fog

Which fog forms when cold, dry air moves over a warm, wet surface such as a lake or after rain?

Steam fog

In winter, thunderstorms are most likely to form along:

Frontal boundaries, especially strong cold fronts

A sea or land breeze is caused by

Differential heating between land and water

When a cold front passes through an area, which set of changes is most likely to occur?

Temperature drops, wind shifts NW, pressure rises, precipitation occurs

What type of fog forms as moist, stable air moves upwards along terrain?

Upslope fog

Thunderstorms which produce tornadoes:

Supercells with rotating updrafts

 32. What actions should a pilot take when encountering a microburst on approach

Full power, pitch for climb, and go around

All thunderstorms require:

Moisture, instability, and a lifting mechanism

Flying through a downburst a pilot can expect:

Rapid wind shift, turbulence, possible altitude and airspeed loss

A bow echo (shaped like a bow on radar) is dangerous and can cause tornadoes

True

What does AO2 signify in a METAR

has a precipitation sensor

Do urban heat islands generate surface highs or surface lows?

Surface lows

Which type of thunderstorm forms when strong directional wind shear creating a rotating updraft?

Supercell

39. The coldest temperatures would most likely at position (1, 2, 3, 4)
Answer: 4 (the cold air is behind the cold front)

40. Falling pressure would probably be observed at (1, 2, 3, 4)
Answer: 1, 2 and 3

41. Heavy snow would most likely be observed at (1, 2, 3, 4)
Answer: 2

What is the difference between a single-cell and a supercell thunderstorm?

Supercells have rotating updrafts (mesocyclones) and longer life; single-cell are short-lived, non-rotating

Which stage of an air mass thunderstorm is marked by precipitation falling to the ground?

Mature Stage

. Where does Clear Air Turbulence Occur?

Upper troposphere near jet streams, often cloudless

What is the life cycle of a single cell thunderstorm?

Cumulus → mature → dissipating

What type of front typically occurs behind a squall line?

Cold front

What are the characteristics of a continental polar air mass in the summer?

Cool, dry, stable, little moisture

In a low pressure system convergence occurs _______.

At the surface

What are the characteristics of a Severe Thunderstorm?

Hail ≥1 inch, winds ≥50 knots, possible tornado

What are the types of cooling fogs?

Radiation, advection, upslope, and valley fog

What causes the downdraft in the mature stage of a single cell thunderstorm?

Falling precipitation dragging air down, enhanced by evaporative cooling

The wind speed generally increases with height above earth’s surface because

Reduced friction with the surface

_______ ice is the most dangerous type because it forms as water droplets impact an aircraft, freeze slowly and spread over the aircraft components

Clear ice

6. Decode the following METAR report KSTL 200232Z 26015G25KT 7SM -TSRA BKN017 OVC032CB 13/10 A2972 RMK AO2 WSHFT 0215 TSE00B32 FROPA FRQ LTGICCG S-SW TS S-SW MOV NE P0000
Answer:

• KSTL → St. Louis Airport

• 200232Z → 20th day at 0232 Zulu

• 26015G25KT → Wind 260° at 15 kt, gust 25 kt

• 7SM → Visibility 7 statute miles

• -TSRA → Light thunderstorm rain

• BKN017 OVC032CB → Broken clouds 1,700 ft, overcast 3,200 ft, cumulonimbus

• 13/10 → Temp 13°C, dewpoint 10°C

• A2972 → Altimeter 29.72 inHg

• RMK AO2 → Automated station with precipitation sensor

• WSHFT 0215 → Wind shift at 0215 Zulu

• TSE00B32 → Thunderstorm began at 0 minutes past hour, cloud base 3,200 ft

• FROPA FRQ → Frequent frost/frozen precipitation

• LTGICCG S-SW → Lightning IC and CG, moving S-SW

• TS S-SW MOV NE → Thunderstorm moving NE

• P0000 → No precipitation accumulation