1w071n-02 CDC Volume 3
Up to date CDC quiz for 1W071A-02 Vol 3 (as of 13 FEB 13)
Questions and Answers
- 1.
Aside from the Air Force Operational Weather Squadrons (OWS), what agency produces discussions on model output?
- A.
Joint Army Air Force Weather Information Network.
- B.
Air Force Weather Agency.
- C.
National Weather Service.
- D.
Air Weather Service.
Correct Answer
C. National Weather Service.Explanation
The National Weather Service is the agency that produces discussions on model output, in addition to the Air Force Operational Weather Squadrons. The Joint Army Air Force Weather Information Network, Air Force Weather Agency, and Air Weather Service are not responsible for producing these discussions.Rate this question:
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- 2.
What areas do Storm Prediction Center advisory charts outline?
- A.
Areas of expected crosswinds.
- B.
Areas of expected severe weather.
- C.
Areas of frequent crosswind occurrence.
- D.
Areas of frequent severe weather occurrence.
Correct Answer
B. Areas of expected severe weather.Explanation
The Storm Prediction Center advisory charts outline areas where severe weather is expected. These charts provide information on the likelihood of severe weather events such as tornadoes, thunderstorms, and hail. By identifying these areas, the charts help to alert and inform the public, emergency responders, and other relevant parties about the potential risks and allow them to take necessary precautions.Rate this question:
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- 3.
What do you physically compare the 00-hour forecast with during the initialization step of the verification, initialization and verification (VIV) process?
- A.
Analysis.
- B.
12-hour forecast.
- C.
24-hour forecast.
- D.
Previous 12-hour forecast.
Correct Answer
A. Analysis.Explanation
During the initialization step of the verification, initialization, and verification (VIV) process, the 00-hour forecast is physically compared with the analysis. The analysis is a representation of the current state of the atmosphere based on observations. By comparing the forecast with the analysis, meteorologists can assess the accuracy of the initial conditions used in the forecast model and make adjustments if necessary. This step helps ensure that the forecast starts from a realistic starting point before proceeding with the verification and further forecasting.Rate this question:
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- 4.
What action is the final step of the verification, initialization and verification process?
- A.
Verify the 00-hour forecast with your current analysis.
- B.
Verify the 12-hour forecast with real-time data for the same time.
- C.
Verify the previous 12-hour forecast with the current 12-hour forecast.
- D.
Verify the previous 12-hour forecast against the current 00-hour forecast.
Correct Answer
B. Verify the 12-hour forecast with real-time data for the same time.Explanation
The final step of the verification, initialization, and verification process is to verify the 12-hour forecast with real-time data for the same time. This step ensures that the forecast made 12 hours ago aligns with the actual conditions observed at that time. By comparing the forecast with real-time data, any discrepancies or inaccuracies in the forecast can be identified and adjustments can be made if necessary. This verification step helps to improve the accuracy and reliability of the forecast.Rate this question:
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- 5.
What initial conditions are models used based upon?
- A.
Standard atmospheric conditions.
- B.
Previously forecasted conditions.
- C.
Current weather observations.
- D.
Model of choice conditions.
Correct Answer
C. Current weather observations.Explanation
Models used in weather forecasting are based on current weather observations. These observations include data such as temperature, humidity, wind speed, and atmospheric pressure. By analyzing these current conditions, meteorologists can input the data into weather models to generate forecasts. These models use complex mathematical equations to simulate the behavior of the atmosphere and predict future weather patterns. Therefore, current weather observations serve as the initial conditions for these models, allowing them to make accurate predictions about future weather conditions.Rate this question:
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- 6.
What action is the goal of severe weather analysis?
- A.
Identify the preconditions that allow storms to become severe.
- B.
Identify the different types of severe thunderstorms.
- C.
Determine the rear-flank downdraft wind direction.
- D.
Determine the mid-level wind speed and direction.
Correct Answer
A. Identify the preconditions that allow storms to become severe.Explanation
The goal of severe weather analysis is to identify the preconditions that allow storms to become severe. This involves analyzing various factors such as atmospheric conditions, temperature, humidity, and wind patterns to determine the likelihood of a storm becoming severe. By identifying these preconditions, meteorologists can issue timely warnings and take appropriate measures to mitigate the potential impact of severe weather events.Rate this question:
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- 7.
How many minutes do single-cell storms typically last?
- A.
20 to 30.
- B.
20 to 40.
- C.
30 to 45.
- D.
30 to 60.
Correct Answer
D. 30 to 60.Explanation
Single-cell storms typically last between 30 to 60 minutes.Rate this question:
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- 8.
Which characteristic is not one of the single-cell thunderstorm?
- A.
Storm motion equal to the mean wind in the lowest 5km to 7km.
- B.
Weak vertical and horizontal wind shear.
- C.
High winds and hail.
- D.
Frequent tornadoes.
Correct Answer
D. Frequent tornadoes.Explanation
The characteristic that is not one of the single-cell thunderstorm is frequent tornadoes. Single-cell thunderstorms are typically short-lived and do not have the necessary conditions to produce frequent tornadoes. While they may have high winds and hail, and weak vertical and horizontal wind shear, tornadoes are not commonly associated with single-cell thunderstorms.Rate this question:
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- 9.
Where do multi-cell storms typically regenerate?
- A.
Along the gust front.
- B.
The rear-flank downdraft.
- C.
East of the westernmost cell.
- D.
North of the 700mb wind maximum.
Correct Answer
A. Along the gust front.Explanation
Multi-cell storms typically regenerate along the gust front. The gust front is the leading edge of cold air that rushes out from the downdraft of a thunderstorm. As this cold air collides with warm, moist air ahead of the storm, it lifts the warm air, creating new updrafts and initiating the formation of new storm cells. This process of regeneration along the gust front allows multi-cell storms to continue and persist over an extended period of time.Rate this question:
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- 10.
Which characteristic is not one of multi-cell thunderstorms?
- A.
Weak directional shear in the lower levels.
- B.
Straight-line or unidirectional profile.
- C.
Large hail near downdraft centers.
- D.
Short-duration tornadoes.
Correct Answer
A. Weak directional shear in the lower levels.Explanation
Multi-cell thunderstorms are characterized by a straight-line or unidirectional profile, large hail near downdraft centers, and short-duration tornadoes. However, weak directional shear in the lower levels is not a characteristic of multi-cell thunderstorms. Directional shear refers to the change in wind direction with height, and in multi-cell thunderstorms, there is typically a stronger directional shear present. Weak directional shear can be associated with single-cell thunderstorms or other types of weather systems.Rate this question:
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- 11.
Which thunderstorm is not a type of supercell thunderstorm?
- A.
Classic.
- B.
High precipitation.
- C.
Low precipitation.
- D.
Moderate precipitation.
Correct Answer
D. Moderate precipitation.Explanation
Moderate precipitation is not a type of supercell thunderstorm because supercell thunderstorms are characterized by strong rotating updrafts, which create severe weather conditions such as large hail, strong winds, and tornadoes. Moderate precipitation refers to a level of rainfall that is neither very high nor very low, and it does not specifically indicate the presence of a supercell thunderstorm. Therefore, it is not considered a type of supercell thunderstorm.Rate this question:
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- 12.
What size hail do classic supercell thunderstorms typically produce?
- A.
Marble.
- B.
Softball.
- C.
Golf ball.
- D.
Baseball.
Correct Answer
C. Golf ball.Explanation
Classic supercell thunderstorms typically produce hail the size of a golf ball. Hail is formed when there are strong updrafts in the storm that carry raindrops upward into extremely cold areas of the storm, causing them to freeze. As the frozen raindrops are carried by the updrafts, they collide with supercooled water droplets, causing them to freeze onto the hailstone and grow in size. The size of the hailstone is determined by the strength of the updrafts and the amount of supercooled water available. In classic supercell thunderstorms, which are known for their intense updrafts, golf ball-sized hail is commonly observed.Rate this question:
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- 13.
Which type of supercell thunderstorm is most commonly found along the dry line of west Texas?
- A.
Moderate-precipitation.
- B.
High-precipitation.
- C.
Low-precipitation.
- D.
Classic.
Correct Answer
C. Low-precipitation.Explanation
Low-precipitation supercell thunderstorms are most commonly found along the dry line of west Texas. These storms typically have a smaller amount of precipitation compared to other types of supercells, which means they produce less rainfall. The dry line acts as a boundary between dry desert air and moist air from the Gulf of Mexico, creating ideal conditions for the formation of low-precipitation supercells. These storms often have a more organized structure and are known for producing severe weather, including tornadoes and large hail, but with less rainfall.Rate this question:
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- 14.
Which region is not a primary source for airmasses?
- A.
Arctic.
- B.
Tropical.
- C.
Equatorial.
- D.
Temperate.
Correct Answer
D. Temperate.Explanation
The temperate region is not a primary source for airmasses because it is located between the polar and tropical regions. Airmasses typically form in the polar and tropical regions due to the temperature and moisture differences. The temperate region is where these airmasses often collide and interact, resulting in weather changes such as fronts and storms. Therefore, while the temperate region plays a significant role in weather patterns, it is not a primary source for airmasses.Rate this question:
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- 15.
What letter or symbol is appended to the label of a modifying airmass that is cooler than the ground below?
- A.
Plus symbol.
- B.
Lower case c.
- C.
Lower case k.
- D.
Minus symbol.
Correct Answer
C. Lower case k.Explanation
When a modifying airmass is cooler than the ground below, the letter "k" is appended to its label. This convention is used in meteorology to indicate that the airmass is colder than the surface it is moving over. The "k" stands for "kool," which is a phonetic representation of the word "cool." Therefore, the correct answer is lower case k.Rate this question:
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- 16.
Where is the geographic area known as the “Great Plains” located?
- A.
West of the Rocky Mountains.
- B.
East of the Appalachian Mountains.
- C.
Between the Mississippi River and the Rocky Mountains.
- D.
Between the Appalachian Mountains and the Missouri River.
Correct Answer
C. Between the Mississippi River and the Rocky Mountains.Explanation
The Great Plains is a vast and flat geographic area located between the Mississippi River and the Rocky Mountains. This region covers parts of the United States and Canada, including states such as North Dakota, South Dakota, Nebraska, Kansas, and Oklahoma. It is characterized by its grasslands, agricultural productivity, and its importance as a transportation corridor.Rate this question:
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- 17.
In what tornado-producing airmass do tornadoes most frequently occur in families, with paths that are commonly long and wide?
- A.
Type II, Gulf Coast type.
- B.
Type I, Great Plains type.
- C.
Type III, Pacific Coast type.
- D.
Type IV, Inverted “V” type.
Correct Answer
B. Type I, Great Plains type.Explanation
Tornadoes most frequently occur in families with long and wide paths in the Great Plains type of tornado-producing airmass. This is because the Great Plains region, located in the central part of the United States, is known for its favorable atmospheric conditions for tornado formation. The flat terrain, warm moist air from the Gulf of Mexico, and cool dry air from the Rocky Mountains create an ideal environment for the development of severe thunderstorms and tornadoes.Rate this question:
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- 18.
What factor is evident above the inversion with a Type I airmass?
- A.
Moisture increase.
- B.
Rapid drying.
- C.
Condensation.
- D.
Turbulence.
Correct Answer
B. Rapid drying.Explanation
The factor that is evident above the inversion with a Type I airmass is rapid drying. This means that as the airmass rises above the inversion layer, the moisture content decreases quickly. This can be attributed to the fact that the inversion layer acts as a barrier, preventing the mixing of air masses and trapping the moisture below it. As the air rises above the inversion, it encounters drier air from above, causing the moisture to rapidly decrease.Rate this question:
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- 19.
Which type of airmass is tropical in origin and generally warm and moist?
- A.
Type I Great Plains.
- B.
Type II Gulf Coast.
- C.
Type III Pacific Coast.
- D.
Type IV Inverted V.
Correct Answer
B. Type II Gulf Coast.Explanation
The correct answer is Type II Gulf Coast. The Gulf Coast region is known for its warm and moist climate due to its proximity to the Gulf of Mexico. This region experiences a tropical air mass, which is characterized by its origin in the tropics and its warm and moist nature. Therefore, Type II Gulf Coast is the correct answer as it aligns with the description of a tropical air mass that is warm and moist.Rate this question:
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- 20.
Which type of airmass has cold air at all levels?
- A.
Type I Great Plains.
- B.
Type II Gulf Coast.
- C.
Type III Pacific Coast.
- D.
Type IV Inverted V.
Correct Answer
C. Type III Pacific Coast.Explanation
Type III Pacific Coast is the correct answer because this type of airmass is characterized by cold air at all levels. The Pacific Coast region experiences the influence of cold ocean currents, which results in the development of cold and stable air masses. These air masses bring cold temperatures and often lead to foggy and damp conditions along the coast.Rate this question:
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- 21.
Which air mass is cold with surface temperatures ranging from 50°F to 68°F, the relative humidity commonly exceeding 70 percent at all levels up to at least 500mb, and average windspeeds of 15 knots at 850mb and 50 knots at 500mb?
- A.
Type II Gulf Coast.
- B.
Type I Great Plains.
- C.
Type III Pacific Coast.
- D.
Type IV Inverted V.
Correct Answer
C. Type III Pacific Coast.Explanation
The given description matches the characteristics of Type III Pacific Coast air mass. It is cold with surface temperatures ranging from 50°F to 68°F, has high relative humidity exceeding 70 percent at all levels up to at least 500mb, and average windspeeds of 15 knots at 850mb and 50 knots at 500mb. This air mass is commonly found along the Pacific Coast.Rate this question:
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- 22.
Which type of airmass features maritime polar air overrunning continental tropical air between 5,000 and 8,000 feet above the surface?
- A.
Type II Gulf Coast.
- B.
Type I Great Plains.
- C.
Type IV Inverted V.
- D.
Type III Pacific Coast.
Correct Answer
C. Type IV Inverted V.Explanation
The correct answer is Type IV Inverted V. This type of airmass occurs when maritime polar air moves over continental tropical air at an altitude between 5,000 and 8,000 feet above the surface. The term "Inverted V" refers to the shape of the temperature profile, where the temperature increases with height initially before decreasing again. This pattern is common along the West Coast of the United States and can lead to unstable weather conditions.Rate this question:
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- 23.
What kind of dew-point temperature difference should exist across a dry line?
- A.
< 10o F degrees.
- B.
> 10oF degrees.
- C.
< 10oC degrees.
- D.
> 10oC degrees.
Correct Answer
B. > 10oF degrees.Explanation
A dew-point temperature difference greater than 10oF degrees should exist across a dry line. This means that the air on one side of the dry line is significantly drier than the air on the other side. The larger the temperature difference, the stronger the dry line is.Rate this question:
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- 24.
What severe weather synoptic pattern’s airmass is typically Type III?
- A.
Type C, overrunning.
- B.
Type D, cold core.
- C.
Type A, dry line.
- D.
Type B, frontal.
Correct Answer
B. Type D, cold core.Explanation
The correct answer is Type D, cold core. In a cold core synoptic pattern, the airmass is typically Type III. Cold core systems are characterized by a low-pressure area aloft and a cold airmass at upper levels. These systems often bring unstable weather conditions, including thunderstorms and heavy precipitation. The cold core airmass is associated with the development of cyclones and is commonly found in the mid-latitudes.Rate this question:
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- 25.
When does the maximum severe activity occur with a major cyclone?
- A.
A few hours after sunrise to maximum heating.
- B.
From time of maximum heating to a few hours after sunset.
- C.
Just before and after maximum heating.
- D.
Only during maximum heating.
Correct Answer
B. From time of maximum heating to a few hours after sunset.Explanation
During a major cyclone, the maximum severe activity occurs from the time of maximum heating to a few hours after sunset. This is because the intense heating of the sun during the day leads to the development of strong updrafts and instability in the atmosphere, which fuels the cyclone's intensity. As the sun sets, the heating decreases, causing the activity to gradually diminish. Therefore, the period from maximum heating to a few hours after sunset is when the cyclone reaches its peak severity.Rate this question:
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- 26.
What wind speeds do you focus on at the 200 and 30 millibar level for severe weather analysis?
- A.
76 knots.
- B.
80 knots.
- C.
86 knots.
- D.
90 knots.
Correct Answer
C. 86 knots.Explanation
The wind speeds focused on at the 200 and 30 millibar level for severe weather analysis are 86 knots. This indicates that strong winds at these levels can be indicative of severe weather conditions.Rate this question:
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- 27.
In straight line flow, what quadrants are the main diffluent areas of a jet maximum?
- A.
Left & right rear.
- B.
Left & right front.
- C.
Left front & right rear.
- D.
Left rear & right front.
Correct Answer
C. Left front & right rear.Explanation
In straight line flow, the main diffluent areas of a jet are the left front and right rear quadrants. This means that the jet is spreading out more in these areas compared to the other quadrants. The left front quadrant refers to the area on the left side of the jet at the front, while the right rear quadrant refers to the area on the right side of the jet at the rear. These areas experience the maximum spread or diffusion of the jet flow.Rate this question:
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- 28.
Which quadrant in the jet max should you look for positive vorticity advection?
- A.
Left rear.
- B.
Right rear.
- C.
Left front.
- D.
Right front.
Correct Answer
B. Right rear.Explanation
Positive vorticity advection refers to the horizontal transport of air with positive vorticity (spin) in the atmosphere. In the Northern Hemisphere, positive vorticity advection is typically associated with cyclonic systems. The jet max, or jet stream, is a region of strong winds in the upper atmosphere. In the Northern Hemisphere, air to the right of the jet stream tends to have positive vorticity advection. Therefore, in the jet max, one should look for positive vorticity advection in the right rear quadrant.Rate this question:
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- 29.
At which pressure level is strong wind needed for thunderstorms to become severe?
- A.
300 millibars.
- B.
500 millibars.
- C.
700 millibars.
- D.
850 millibars.
Correct Answer
B. 500 millibars.Explanation
At the 500 millibar pressure level, strong winds are needed for thunderstorms to become severe. This is because the 500 millibar pressure level is located in the middle layers of the atmosphere and is associated with the jet stream, which is a fast-moving air current. The strong winds at this level can provide the necessary dynamics and instability for thunderstorms to intensify and become severe.Rate this question:
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- 30.
What does positive vorticity advection indicate?
- A.
Divergence or upward vertical motion.
- B.
Convergence or upward vertical motion.
- C.
Divergence or downward vertical motion.
- D.
Convergence or downward vertical motion.
Correct Answer
A. Divergence or upward vertical motion.Explanation
Positive vorticity advection indicates divergence or upward vertical motion. Vorticity refers to the rotation of fluid particles in a fluid flow. Positive vorticity advection occurs when an area of higher vorticity is transported into a region, causing the fluid to spread out or diverge. This divergence leads to upward vertical motion as the fluid particles move away from each other. Therefore, positive vorticity advection is associated with divergence or upward vertical motion.Rate this question:
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- 31.
What parameters are the two most important to analyze at 700 millibars?
- A.
No-change line and dry-air intrusion.
- B.
No-change line and wind maximums.
- C.
Dew point temperatures and dry-air intrusion.
- D.
Wind maximums and dew point temperatures.
Correct Answer
A. No-change line and dry-air intrusion.Explanation
At 700 millibars, the two most important parameters to analyze are the no-change line and dry-air intrusion. The no-change line indicates areas where the temperature remains constant, which can be crucial for understanding weather patterns. Dry-air intrusion refers to the intrusion of dry air into a region, which can impact humidity levels and precipitation. By analyzing these two parameters, meteorologists can gain valuable insights into atmospheric conditions and make more accurate weather predictions.Rate this question:
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- 32.
What weather characteristic does the 700 millibars no change line usually line up with?
- A.
Trough axis.
- B.
Surface front.
- C.
Low-level jet.
- D.
850 millibar warm ridge.
Correct Answer
D. 850 millibar warm ridge.Explanation
The 700 millibars no change line usually lines up with the 850 millibar warm ridge. This means that at the 700 millibar level in the atmosphere, there is little to no change in weather conditions, and this is typically associated with the presence of a warm ridge at the 850 millibar level. The warm ridge is an area of high pressure and warm air aloft, which can lead to stable and fair weather conditions.Rate this question:
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- 33.
Which zone is not a type of surface convergent zone?
- A.
Dry line.
- B.
Frontal boundary.
- C.
Land breeze front.
- D.
Outflow boundary.
Correct Answer
C. Land breeze front.Explanation
The question is asking which option is not a type of surface convergent zone. A surface convergent zone is a region where air masses of different characteristics come together and converge. The options "Dry line," "Frontal boundary," and "Outflow boundary" are all examples of surface convergent zones. However, a "Land breeze front" is not a type of surface convergent zone. A land breeze front occurs when cooler air from the land moves towards a body of water, creating a boundary between the two air masses.Rate this question:
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- 34.
How far ahead of a cold front do pre-frontal squall lines form?
- A.
25 to 125 statute miles.
- B.
50 to 150 statute miles.
- C.
25 to 125 nautical miles.
- D.
50 to 150 nautical miles.
Correct Answer
D. 50 to 150 nautical miles.Explanation
Pre-frontal squall lines are a type of severe weather that forms ahead of a cold front. They are characterized by a line of intense thunderstorms that can produce strong winds, heavy rain, and even tornadoes. The correct answer, 50 to 150 nautical miles, suggests that pre-frontal squall lines typically form within this distance range in front of the cold front. This means that these severe weather conditions can occur anywhere from 50 to 150 nautical miles ahead of the approaching cold front.Rate this question:
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- 35.
What does a >+1 on the Showalter stability index suggest?
- A.
Strong stability.
- B.
Strong instability.
- C.
Moderate stability.
- D.
Moderate instability.
Correct Answer
C. Moderate stability.Explanation
A ">+1" on the Showalter stability index suggests moderate stability. The symbol ">" indicates that the stability is greater than a certain value, in this case, +1. The term "moderate" implies that the stability is not extremely strong or weak, but falls somewhere in between. Therefore, a ">+1" suggests that the system is moderately stable, indicating a relatively balanced and steady state.Rate this question:
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- 36.
What does a lifted index (LI) greater than zero indicate?
- A.
Stability.
- B.
Instability.
- C.
No severe weather - winds too strong.
- D.
Severe weather likely, chance of tornadoes.
Correct Answer
A. Stability.Explanation
A lifted index (LI) greater than zero indicates stability. Stability refers to atmospheric conditions that resist vertical air movement, which inhibits the development of severe weather. When the LI is greater than zero, it suggests that the air is stable and less likely to produce thunderstorms or other severe weather events.Rate this question:
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- 37.
What weather occurrence does a severe weather threat index of 650 indicate?
- A.
Severe thunderstorms likely, chance of tornadoes.
- B.
Severe thunderstorms and tornadoes likely.
- C.
No severe weather – winds too strong.
- D.
Tornadoes nearly always occur.
Correct Answer
D. Tornadoes nearly always occur.Explanation
A severe weather threat index of 650 indicates that tornadoes nearly always occur. This means that the conditions are extremely favorable for tornado formation and there is a high probability of tornadoes happening. The index value suggests that the threat level is significant and people should take immediate precautions to ensure their safety.Rate this question:
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- 38.
What atmospheric event does a negative convective available potential energy indicate?
- A.
Increased warm moist air advection.
- B.
Decreased cold dry air advection.
- C.
Downward vertical motions.
- D.
Upward vertical motions.
Correct Answer
C. Downward vertical motions.Explanation
A negative convective available potential energy (CAPE) indicates downward vertical motions in the atmosphere. CAPE is a measure of the amount of energy available for convection, which is the vertical movement of air. When CAPE is negative, it means that the atmosphere is stable and not conducive to upward vertical motions or convection. Instead, it suggests that there are downward vertical motions, which typically result in subsidence and sinking air.Rate this question:
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- 39.
What weather feature is commonly found south of the center of a low pressure system and is indicated by a relatively cloud-free region?
- A.
Warm front.
- B.
Cold front.
- C.
Dry line.
- D.
Dry slot.
Correct Answer
D. Dry slot.Explanation
A dry slot is commonly found south of the center of a low pressure system and is indicated by a relatively cloud-free region. This occurs when dry air is pulled into the system, creating a clear area amidst the surrounding clouds. It is a result of the interaction between warm and cold air masses, causing the dry air to wrap around the low pressure system and create a region of clearing.Rate this question:
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- 40.
Which atmospheric occurrence is not a type of lifting mechanism for convection?
- A.
Convection.
- B.
Frontal lifting.
- C.
Decompression.
- D.
Orographic lifting.
Correct Answer
C. Decompression.Explanation
Decompression is not a type of lifting mechanism for convection. Convection refers to the transfer of heat through the movement of fluids, such as air or water. Frontal lifting occurs when warm and cold air masses collide, causing the warm air to rise. Orographic lifting happens when air is forced to rise over a mountain or elevated terrain. However, decompression does not involve the vertical movement of air but rather the reduction of atmospheric pressure, which can lead to the expansion of gases.Rate this question:
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- 41.
What number of feet must the freezing level be for most precipitation to reach the surface as snow?
- A.
1,000.
- B.
1,100.
- C.
1,200.
- D.
1,300.
Correct Answer
C. 1,200.Explanation
The freezing level refers to the altitude at which the temperature drops to 0 degrees Celsius (32 degrees Fahrenheit), causing precipitation to freeze and fall as snow. Therefore, for most precipitation to reach the surface as snow, the freezing level must be at or below the surface. Among the given options, 1,200 feet is the closest to the surface, making it the correct answer.Rate this question:
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- 42.
For the Weather Service Radar (WSR)–88D to generate a base reflectivity product, the antenna must complete
- A.
One elevation slice.
- B.
One complete 360° circle.
- C.
An entire volume coverage pattern.
- D.
At least two complete volume coverage patterns.
Correct Answer
A. One elevation slice.Explanation
To generate a base reflectivity product, the Weather Service Radar (WSR) 88D antenna must complete one elevation slice. This means that the radar antenna needs to scan a single vertical layer of the atmosphere at various angles to gather data on the reflectivity of precipitation particles within that layer. This information is then used to create a base reflectivity product, which shows the intensity of precipitation in a specific area. The other options, such as completing a 360° circle or multiple volume coverage patterns, are not necessary for generating a base reflectivity product.Rate this question:
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- 43.
Which decibel (dBZ) value is considered the approximate precipitable/non-precipitable threshold?
- A.
–30 dBZ.
- B.
–18 dBZ.
- C.
+18 dBZ.
- D.
+30 dBZ.
Correct Answer
C. +18 dBZ.Explanation
The approximate precipitable/non-precipitable threshold is considered to be +18 dBZ. Decibel (dBZ) values are used in weather radar to measure the intensity of precipitation. A value of +18 dBZ indicates light precipitation, which is generally considered to be the threshold for determining whether precipitation is occurring or not.Rate this question:
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- 44.
What does the line echo wave pattern (LEWP) signature mean to a forecaster?
- A.
A favorable environment exists for severe weather development.
- B.
High pressure is forming and the threat of severe weather has ended.
- C.
Continued thunderstorm development is certain but severe weather is unlikely.
- D.
The current state of the atmosphere is much too stable for severe weather development.
Correct Answer
A. A favorable environment exists for severe weather development.Explanation
The line echo wave pattern (LEWP) signature indicates a favorable environment for severe weather development. This means that conditions are conducive for the formation and intensification of severe weather events such as thunderstorms, tornadoes, or heavy rainfall. The LEWP signature is a valuable tool for forecasters as it helps them identify the potential for severe weather and issue appropriate warnings to the public.Rate this question:
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- 45.
Embedded thunderstorms are detected by the Weather Service Radar (WSR)–88D quite well because
- A.
It uses airborne radar technology to seek out these storms.
- B.
The storms move much faster than the surrounding precipitation.
- C.
Its 10cm wavelength can see through the stratiform precipitation.
- D.
The storms move much slower than the surrounding precipitation.
Correct Answer
C. Its 10cm wavelength can see through the stratiform precipitation.Explanation
The correct answer is that the WSR-88D radar can detect embedded thunderstorms well because its 10cm wavelength can see through the stratiform precipitation. This means that the radar can penetrate through the lighter, more uniform precipitation that often accompanies thunderstorms, allowing it to identify the embedded thunderstorms within. The radar's ability to see through the stratiform precipitation helps in accurately detecting and tracking these storms.Rate this question:
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- 46.
Outflow boundaries may be seen on the Weather Service Radar (WSR)–88D even when no clouds are present because
- A.
The WSR–88D can detect returns of greater than +18dBZ.
- B.
Precipitable water is present although it is not visible to the human eye.
- C.
Low-level wind shear is usually present with the boundary, making it more visible.
- D.
A gradient in the refractive index due to density differences that exist with the boundary.
Correct Answer
D. A gradient in the refractive index due to density differences that exist with the boundary.Explanation
Outflow boundaries may be seen on the Weather Service Radar (WSR)–88D even when no clouds are present because there is a gradient in the refractive index due to density differences that exist with the boundary. This means that there is a change in the density of the air within the boundary, which affects the way that the radar waves are refracted. As a result, the radar is able to detect these density differences and display them as outflow boundaries on the radar screen, even if there are no visible clouds present.Rate this question:
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- 47.
Which product is used in the detection and location of rotating thunderstorms and in determining wind field characteristics?
- A.
Base reflectivity.
- B.
Base radial velocity.
- C.
Severe weather analysis.
- D.
Severe weather probability.
Correct Answer
B. Base radial velocity.Explanation
Base radial velocity is the correct answer because it is a product used in the detection and location of rotating thunderstorms and in determining wind field characteristics. Radial velocity measures the speed and direction of motion of objects towards or away from a radar, and by analyzing the radial velocities of precipitation particles, meteorologists can identify rotation within thunderstorms and assess the wind patterns associated with them. Base reflectivity, severe weather analysis, and severe weather probability are not specifically focused on detecting rotating thunderstorms or determining wind field characteristics.Rate this question:
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- 48.
When the Doppler zero line has a noticeable S-shaped pattern, winds are considered to be
- A.
From 270°.
- B.
Veering with height.
- C.
Backing with height.
- D.
Increasing with height.
Correct Answer
B. Veering with height.Explanation
When the Doppler zero line has a noticeable S-shaped pattern, it indicates that the winds are veering with height. Veering refers to a change in wind direction in a clockwise manner with increasing height. This S-shaped pattern is often observed in the lower atmosphere and is caused by the interaction of wind with various features such as topography or frontal boundaries. It signifies a change in wind direction with height, which is characteristic of veering winds.Rate this question:
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- 49.
Which concept should be considered when trying to determine hail size?
- A.
Strength of the updraft.
- B.
Rotation at the base of the storm.
- C.
Strength of the convergence aloft.
- D.
Rotation in the mid-levels of the storm.
Correct Answer
A. Strength of the updraft.Explanation
When trying to determine hail size, the concept that should be considered is the strength of the updraft. An updraft refers to the upward movement of air within a storm. The stronger the updraft, the more likely it is to support the growth of larger hailstones. This is because a strong updraft can keep the hailstones suspended in the storm for a longer period of time, allowing them to accumulate more layers of ice and grow in size. Therefore, the strength of the updraft is a crucial factor in determining the size of hail that can be produced by a storm.Rate this question:
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- 50.
The spectrum width product is most effective when
- A.
Used alone.
- B.
Used with other products.
- C.
Displayed in 16 data levels.
- D.
Overlaid on composite reflectivity.
Correct Answer
B. Used with other products.Explanation
The spectrum width product is most effective when used with other products. This is because the spectrum width provides information about the variability of the Doppler velocities within a radar beam, but it does not provide a complete picture of the weather conditions. By combining the spectrum width with other products such as reflectivity or velocity, meteorologists can gain a more comprehensive understanding of the atmospheric conditions and make more accurate weather predictions.Rate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Feb 13, 2013Quiz Created by
USAFWX
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