Deck 13: Weather Forecasting

Question 1

Computer forecast models make certain assumptions about the atmosphere that are not always correct.

Answer 1

True

Question 2

The AWIPS system is designed to provide nearly continuous information about wind, temperature, pressure, cloud-base height, and runway visibility at various airports.

Answer 2

False

Question 3

A weather watch would probably be issued for which of the following conditions?

A)There is a chance for tornadoes tomorrow.
B)Presently, extremely high winds are occurring at mountain summits.
C)A tornado has been sighted at the outskirts of town.
D)Heavy snow has been falling over the forecast area.
E)There is a chance of rain tomorrow.

Answer 3

A

Question 4

An anticyclone is moving slowly eastward. Southerly winds on the western side of the system will bring warmer and more humid air to the region. Therefore, afternoon temperatures will be warmer than those of the day before.

Question 5

Weather forecasts are commonly grouped according to how far into the future the forecast extends.

Question 6

A downside of high-resolution models is that, as the horizontal spacing between grid points decreases, the number of computations increases. When the distance is halved, there are 8 times as many computations to perform, and the time (and computational expense)required to run the model goes up by a factor of 16.

Question 7

These days the precise location where a tornado will form can be predicted up to seven days in advance.

Question 8

Meteorologists interpret the weather patterns and then correct any errors that may be present. The final chart is referred to as a prediction.

Question 9

A forecast that extends beyond three days is often called an extended forecast.

Question 10

A capable forecaster only needs computer models to predict future weather, and does not need a strong sense of how surface features typically evolve.

Question 11

According to the National Weather Service, the subjective term "fair" implies a rather pleasant weather situation.

Question 12

Because the many weather variables are constantly changing, meteorologists have devised atmospheric models that describe the present state of the atmosphere. These are not physical models that paint a picture of a developing storm; they are, rather, mathematical models consisting of many equations that describe how atmospheric temperature, pressure, winds, and moisture will change with time.

Question 13

Surface pressure systems tend to move in the same direction as the wind at 5500 m (18,000 ft)-the 500-mb level. The speed at which surface systems move is about double the speed of the winds at this level.

Question 14

Soundings only provide information that aids in the prediction of fog, air pollution alerts, and the downwind mixing of strong winds.

Question 15

Probably the easiest weather forecast to make is a statistical forecast.

Question 16

Stating that the chance of rain is 60 percent means that there is a 60 percent chance that it will rain within the forecast area.

Question 17

Suppose that it is presently warm and raining. A cold front will pass your area in 3 hours. Behind the front, it is cold and snowing. A persistence forecast would predict warm and rainy weather.

Question 18

Doppler radar is helpful for measuring precipitation, but not wind.

Question 19

For many companies, seasonal outlooks are even more important than day-to-day forecasts.

Question 20

A weather watch indicates that ____.

A)the atmospheric conditions are favorable for hazardous weather over a particular region
B)hazardous weather is either imminent or occurring within the forecast area
C)hazardous weather is likely to occur within the forecast area during the next 24 hours
D)hazardous weather is frequently observed in a particular region
E)hazardous weather is occurring in nearby areas

Question 21

The forecasting of weather by a computer is known as ____.

A)weather type forecasting
B)climatology forecasting
C)extended weather forecasting
D)analog prediction
E)numerical weather prediction

Question 22

A forecast of an extended period of dry weather would be made for a region beneath ____.

A)an upper-level trough
B)the polar jet stream
C)a cold pool of air aloft
D)an upper-level ridge
E)a shortwave trough

Question 23

A probability forecast that calls for a "40 percent chance of rain" means that ____.

A)there is a 40 percent chance that it will not rain within the forecast area
B)there is a 40 percent chance that any random place in the forecast area will receive measurable rain
C)it will rain on 40 percent of the forecast area
D)it will rain during 40 percent of the time over the forecast area
E)it will definitely rain

Question 24

An accurate forecast ____.

A)always shows skill
B)may or may not show skill
C)never shows skill
D)requires complex computer equipment
E)can only be accomplished after many years of experience

Question 25

Meteorological cancer is when ____.

A)a meteorologist develops cancer
B)a meteorologist makes too many forecasting mistakes in his/her career
C)a meteorologist no longer has the necessary skills to make an authoritative forecast
D)a meteorologist relies too much on forecast models, without bringing his/her own knowledge and experience into the forecasting process
E)consumers no longer have confidence in a meteorologist's aptitude

Question 26

The ____ forecasting method assumes that weather systems will move in the same direction and at the same speed as they have been moving.

A)persistence
B)probability
C)weather type
D)climatological
E)steady-state (trend)

Question 27

A forecast method that compares past weather maps and weather patterns to those of the present is ____.

A)persistence forecasting
B)the analog method
C)the trend method
D)nowcasting
E)steady-state forecasting

Question 28

The most direct protection against the risk of weather-related financial downturns comes from ____.

A)linear forecasts
B)persistence forecasts
C)the analog method
D)insurance
E)futures contracts

Question 29

Suppose that where you live, the middle of January is typically several degrees warmer than the rest of the month. If you forecast this "January thaw" for the middle of next January, you would have made a ____.

A)forecast based on the analog method
B)persistence forecast
C)forecast based on weather types
D)probability forecast
E)climatological forecast

Question 30

The greatest improvement in forecasting skill during the past 30 years has been made in forecasting ____.

A)snowstorms along the eastern seaboard
B)the development of middle latitude cyclones in the Pacific Ocean
C)severe storm warnings for hurricanes and tornadoes
D)the movement of warm and cold fronts
E)maximum and minimum temperatures 6 to 10 days into the future

Question 31

By examining a surface map, the movement of a surface low-pressure area can be predicted because ____.

A)low-pressure areas tend to move parallel to isobars of the warm sector
B)lows tend to move toward the area with the greatest pressure
C)movement is the same as it was during the previous 24 hours
D)once a low is established it always moves toward the east at double the original speed
E)current weather in the region will remain the same

Question 32

Automated Surface Observing Systems (ASOS)measure ____.

A)wind speed and direction
B)temperature and pressure
C)cloud-base height
D)runway visibility at various airports
E)All of these are correct.

Question 33

A weather forecast for the immediate future that employs the trend method is called ____.

A)nowcasting
B)extrapolation
C)first-order forecasting
D)linear forecasting
E)persistence forecasting

Question 34

A persistence forecast could be quite accurate when ____.

A)a frontal system approaches your location at a constant speed
B)you are positioned in the middle of a large, stationary air mass
C)the weather has been unusually cold for several days
D)upper-level winds blow straight from west to east
E)when a warm front is approaching

Question 35

A prog is ____.

A)a chart that interprets the current state of the atmosphere
B)an instrument that draws lines on an upper-level chart
C)a new method of forecasting the weather
D)a forecast chart that shows the atmosphere at a specified time
E)another name for a probability forecast

Question 36

An analysis is a ____.

A)forecast chart that shows the atmosphere at some future time
B)forecast chart that compares past weather maps with those of the present
C)surface or upper-level chart that interprets the present weather patterns
D)forecast method used in long-range weather prediction
E)method used to determine skill in predicting the weather

Question 37

For a forecast to show skill it must ____.

A)be better than one based on persistence or climatology
B)be accurate to within 2 degrees Celsius of the predicted temperature
C)be accurate for over more than 90 percent of the forecast area
D)use the analog method of forecasting
E)use a probability

Question 38

What would be the least accurate forecast method of predicting the weather two days into the future during changeable weather conditions?

A)Trend method
B)Persistence forecast
C)Analog method
D)Prediction by weather types
E)Numerical weather prediction

Question 39

A weather forecast that predicts that the future weather will be the same as the present weather is called ____.

A)a steady-state forecast
B)the trend method
C)a persistence forecast
D)the analog method
E)an extended weather forecast

Question 40

Which of the following is a correct statement regarding numerical weather prediction?

A)It uses physical models that paint a picture of a developing storm.
B)It uses mathematical models consisting of one equation that describes how weather conditions will change with time.
C)The models fully represent the real atmosphere.
D)The models are useful approximations.
E)The models are formulated to retain all aspects of the atmosphere's behavior.

Question 41

The principle that "surface weather systems tend to move in the same direction and at approximately the same speed as they have been moving" forms the basis of which type of forecasting method?

A)Persistence forecast
B)Analog method
C)Steady-state forecast
D)Ensemble forecast
E)Nowcast

Question 42

Warm advection is most likely to occur ____.

A)in the center of a cut-off low
B)from the surface up to the 500-mb level ahead of an advancing warm front
C)behind a cold front
D)where the winds back with height
E)on the western side of a shortwave trough at the 500-mb level

Question 43

Lines connecting points of equal pressure change are called ____.

A)isobars
B)isograds
C)contours
D)isotherms.
E)isallobars

Question 44

Which weather advisory is issued when falling or blowing snow and winds of at least 35 miles per hour restrict visibility to less than 1/4 mile for several hours?

A)Blizzard advisory
B)Snow caution
C)Snow advisory
D)Blizzard warning
E)Snow warning

Question 45

Suppose a computer model uses more closely spaced grid points and a greater number of data points, and thus has better resolution. This model will be particularly useful in forecasting _____.

A)large-scale winds
B)a vorticity maximum
C)longwave directions
D)temperatures at the surface
E)the relative position of highs and lows

Question 46

If you wanted to make a persistence forecast of minimum and maximum temperatures for a particular city, the ____ type of chart would be most helpful.

A)surface
B)meteogram
C)500-mb
D)adiabatic
E)Doppler radar display

Question 47

In one forecast, west of San Francisco, the flow is meridional with a cut-off warm, upper high situated just south of Alaska. To the south, both east and west of the high are troughs. Because the shape of this flow around the high resembles a Greek letter, the high and its accompanying ridge are known by this Greek letter; that is, as a(n)____ high.

A)theta
B)gamma
C)omega
D)beta
E)alpha

Question 48

Which of the following is the least likely to be a forecaster's rule of thumb?

A)For short time intervals, mid-latitude cyclonic storms and fronts tend to move in the same direction and at approximately the same speed as they did during the previous six hours.
B)Low-pressure areas tend to move in a direction that parallels the isobars in the warm air sector.
C)Lows tend to move toward the region of greatest pressure drop.
D)Highs tend to move toward the region of greatest pressure drop.
E)A "chance of rain" means that the chance of rain is 30 to 50 percent.

Question 49

Conditions such as high wind speeds, cold air moving southward, warm air moving northward, and a shortwave moving into a longwave trough will typically manifest themselves as a(n)____ of a longwave trough.

A)dissipation
B)stabilization
C)weakening
D)deepening
E)receding

Question 50

As an/a ____ forecast goes further and further into the future, the forecast lines can become scrambled. Such a chart is often referred to as a spaghetti plot.

A)ensemble
B)chaos
C)multilinear
D)filament
E)shifting

Question 51

Warm advection occurs when the ____.

A)wind veers (changes direction in a clockwise manner)with height
B)wind backs (changes direction in a counterclockwise manner)with height
C)isotherms are parallel to the winds
D)wind veers with height and the isotherms are parallel to the winds
E)Sun angle is 90 degrees

Question 52

A comma cloud is ____.

A)an organized band of clouds that looks like a comma on a satellite photograph
B)a large cumulonimbus cloud whose anvil is in the shape of a comma
C)a high wispy cirrus cloud that takes on the shape of a comma
D)the spiraling arms of a hurricane
E)a band of high cirrus clouds blown by the jet stream

Question 53

Thickness charts help forecasters ____.

A)identify cloud patterns
B)locate stratospheric disturbances
C)predict the length of sunshine on a day
D)predict whether falling precipitation will be rain or snow
E)provide information on Sun angles in specific locations

Question 54

Very short-range forecasts are typically for how long of a time?

A)A few minutes
B)Approximately 30 minutes
C)A few hours
D)Approximately 12 hours
E)Approximately 24 hours

Question 55

Which of the following is least likely to be a condition associated with an omega high?

A)It is in the shape of the Greek letter "omega."
B)It is known as a "blocking high."
C)It forms when the flow aloft is zonal.
D)It tends to persist in the same geographic area for many days.
E)It keeps troughs in their positions.

Question 56

Suppose there are two cloud layers above you. The lower cloud layer is moving from a westerly direction, while the higher cloud layer is moving from a northwesterly direction. From this observation you conclude that the wind is ____ with height and ____ advection is occurring between the cloud layers.

A)backing; cold
B)backing; warm
C)veering; cold
D)veering; warm
E)backing; no

Question 57

Which of the following can cause errors in forecasts made by numerical weather prediction models?

A)Computers cannot predict the short-range future.
B)The model captures too many fine scale details.
C)There is too much data to predict the weather.
D)Inadequate representation of pertinent meteorological processes.
E)Too many different types of data are assimilated in a model.

Question 58

A forecast of "precipitation likely" means the probability of precipitation is ____.

A)between 0 and 20 percent
B)between 30 and 50 percent
C)between 50 and 60 percent
D)between 60 and 70 percent
E)greater than 80 percent

Question 59

In the short-range weather forecasts of this chapter, we assumed that the pressure systems and fronts were ____.

A)moving at a constant rate
B)accelerating along a random curve
C)stable and unchanging
D)moving toward zero
E)exactly identical

Question 60

Modern computer forecasting models have increasingly smaller grid spacing. This presents which of the following problems ?

A)Mesoscale weather features can be predicted.
B)Small-scale weather features can be resolved by the models.
C)Many more computations are needed.
D)The vast amount of information makes it difficult to make a prediction.
E)It takes too long to make a prediction.

Question 61

Even with better observing techniques and high-quality computer models, there are countless small, unpredictable atmospheric fluctuations, referred to as ____, that limit model accuracy.

Question 62

The ____________________ describes the steps used by forecasters to steer their attention from large scales to smaller scales and from short time frames to longer periods.

Question 63

Predicting the weather by weather types employs the ____________________.

Question 64

Surface weather information is provided by more than 10,000 land-based stations and hundreds of ships and buoys providing surface weather information at least ____ times a day.

A)2
B)4
C)6
D)8
E)10

Question 65

In the course of a single workday, a typical forecaster may examine and compare ____ individual weather maps.

A)5
B)7
C)10
D)dozens of
E)thousands of

Question 66

A long-range forecast is a forecast that extends beyond approximately ____.

A)8.5 years
B)8.5 months
C)8.5 weeks
D)8.5 days
E)8.5 hours

Question 67

If low clouds at an elevation of 3000 ft above you are moving from the southeast, and clouds about 8000 ft higher are moving from the southwest, ____________________ advection is taking place between the cloud layers.

Question 68

A weather forecast for up to a few hours (usually not more than 6 hours)is called a(n)____________________ forecast, or ____________________.

Question 69

You are in Calgary, Alberta, Canada, 100 km (62 mi)east of the Rockies in January. The current wind is from the north. Looking at a prog for tomorrow, you see that the wind will be from the west, hence tomorrow's temperature will be ____ today's.

A)warmer than
B)colder than
C)the same as
D)colder and drier than
E)the same but more humid than

Question 70

____________________ , which includes more than 175 nations, is responsible for the international exchange of weather data and certifies that the observation procedures do not vary among nations.

Question 71

A blocking high is a ____.

A)high-pressure system and accompanying ridge that change location quickly
B)high-pressure system and accompanying ridge that persist in the same location for many days
C)high-pressure system and accompanying ridge that produce torrential rains
D)ridge associated with a low-pressure system
E)trough associated with a low-pressure system

Question 72

A forecast based on the climate of a particular region is known as a(n)____________________.

Question 73

A weather ____________________ indicates that atmospheric conditions favor hazardous weather occurring over a particular region during a specified time period. A weather ____________________, on the other hand, indicates that hazardous weather is either imminent or actually occurring within the specified forecast area. Advisories are issued to inform the public of less hazardous conditions caused by wind, dust, fog, snow, sleet, or freezing rain.

Question 74

Given a map with isallobars, high-pressure systems tend to move where the isallobars indicate ____________________ values, and low-pressure systems move where the isallobars are ____________________.

Question 75

Suppose that where you live, the middle of January is typically several degrees warmer than the rest of the month. If you forecast this "January thaw" for the middle of next January, you have made a(an)____ type of weather forecast.

A)ensemble
B)common
C)seasonal outlook
D)nowcast
E)probability

Question 76

Another aid in weather forecasting is the use of ____________________, a two-dimensional vertical profile of temperature, dew point, and winds.

Question 77

Suppose that in a summer afternoon, you observe cumulus clouds with limited vertical growth and with tops at just about the same level. Your local weather forecast should be which of the following?

A)Continued partly cloudy with no precipitation; probably clearing by nightfall
B)Possible showers or thunderstorms by afternoon with gusty winds
C)Continued clear to partly cloudy; cool night with low humidity
D)High minimum temperatures
E)Lower minimum temperatures

Question 78

____ tend(s)to steer the movement of surface pressure systems.

A)Cumulus clouds
B)Doppler radar
C)Winds aloft
D)Ensemble forecasts
E)Stationary fronts

Question 79

The NOAA National Centers for Environmental Prediction runs several large-scale forecast models in ____________________ mode, meaning that they have been thoroughly tested and are reliable enough for everyday use. Other models are run in ____________________ mode; these models show promise and may be consulted by forecasters, but they may not yet be robust enough for operational use.

Question 80

Pattern recognition is the common term for what is known as the ____________________ method.