Deck 15: Tornadoes

Question 1

Which of the following terms refers to the forecasting method that produces several versions of a forecast model, each one beginning with slightly different weather information to reflect errors in the measurements?

A)climatological forecasting
B)redundancy analysis
C)ensemble forecasting
D)persistence forecasting

Answer 1

C

Question 2

In which of the following locations is warm advection most likely to occur?

A)from the surface up to the 500 hPa level in front of a warm front
B)in the centre of a cut-off low
C)from the surface up to the 500 hPa level behind a cold front
D)where the winds back with height
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The following questions refer to the above illustration of a middle-latitude cyclone.The dashed lines show the positions of the fronts six hours ago.

Answer 2

A

Question 3

Which of the following conditions would likely prompt the issuing of a weather watch?

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

Answer 3

B

Question 4

Suppose there are two cloud layers above you. The lower cloud layer is moving from a westerly direction, and the higher cloud layer is moving from a northwesterly direction. Which of the following describes the type of wind and type of advection that is likely occurring?

A)a backing wind and cold advection between the cloud layers
B)a veering wind and warm advection between the cloud layers
C)a veering wind and cold advection between the cloud layers
D)a backing wind and warm advection between the cloud layers

Question 5

Which of the following terms refers to the forecasting of weather by computer?

A)extended forecast
B)numerical weather prediction
C)weather-type forecasting
D)climatological forecast

Question 6

Which of the following terms refers to a wind that changes direction in a counterclockwise sense with increasing height?

A)backing wind
B)meridional wind
C)veering wind
D)Ekman spiral
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The following questions refer to the above illustration of a middle-latitude cyclone.The dashed lines show the positions of the fronts six hours ago.

Question 7

Which of the following describes a situation for which the Canadian Meteorological Service would release a warning for a severe thunderstorm?

A)Conditions are favourable for wind gusts of 90 km/h or more
B)Conditions are favourable for less than 50 mm of rainfall.
C)Hail less than 2 cm in diameter is occurring.
D)Winds gusts of 90 km/h or more are occurring.

Question 8

At which location represented by the four positions on the map would you expect to hear the following 12-hour forecast: "Cloudy with possible showers today, turning colder by tonight"?

A)position 1
B)position 2
C)position 3
D)position 4

Question 9

In terms of weather forecasting methods, which of the following defines an analysis?

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

Question 10

For which of the following locations would a forecast of an extended period of dry weather be made?

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

Question 11

Suppose it is warm and raining, and a cold front is moving toward your location. Directly behind the cold front, the weather is cold and snowing, and further behind the front, it is cold and clearing. The front is scheduled to pass your area in six hours. Which of the following describes the persistence forecast for your area 12 hours from now?

A)cold and clearing
B)cold and cloudy
C)cold and snowing
D)warm and raining

Question 12

At which location represented by the four positions on the map would you expect to hear the following 12-hour forecast: "Clearing and colder today with continued rising pressure"?

A)position 1
B)position 2
C)position 3
D)position 4

Question 13

Which of the following problems arise because the grid spacing in modern computer forecasting models has become increasingly smaller?

A)Small-scale weather features can be resolved by the models.
B)Mesoscale weather features cannot be predicted.
C)Atmosphere-oceans interactions cannot be resolved.
D)Many more computations are needed.

Question 14

Which of the following terms refers to a weather forecast that predicts that future weather will be the same as the present weather?

A)trend method
B)steady-state forecast
C)analogue method
D)persistence forecast

Question 15

To develop a persistence forecast of minimum and maximum temperatures for a particular city, which of the following types of charts is most helpful?

A)adiabatic chart
B)surface chart
C)meteogram
D)500 hPa chart

Question 16

Which of the following resources does a meteorologist use to produce an ensemble 500 hPa forecast?

A)radar displays
B)physical climate model
C)upper-air chart
D)surface chart

Question 17

Which of the following statements describes what a weather warning indicates?

A)Hazardous weather is occurring over a forecast area.
B)Hazardous weather is either imminent or occurring within the forecast area.
C)Hazardous weather is frequently observed over a forecast area.
D)Hazardous weather is likely to occur within the forecast area during the next 24 hours.

Question 18

Cyclone
Which of the following terms refers to the lines that connect points of equal pressure change?

A)contours
B)isobars
C)isograds
D)isallobars

Question 19

Which of the following describes a prog?

A)an instrument that draws lines on an upper-level chart
B)a forecast chart that shows the atmosphere at some future time
C)a new method of forecasting the weather
D)a chart that interprets the current state of the atmosphere

Question 20

Which of the following describes the length of a medium-range forecast?

A)2 days
B)7 days
C)15 days
D)30 days

Question 21

Which of the following describes where the greatest improvement in forecasting skill has occurred during the past 30 years?

A)the development of middle-latitude cyclones in the Pacific Ocean
B)snowstorms along the eastern seaboard
C)severe storm warnings for hurricanes and tornadoes
D)the movement of warm and cold fronts

Question 22

Which of the following is currently a problem with modern-day weather predictions?

A)There are regions of the world where observations are sparse.
B)Computer forecast models make assumptions about the atmosphere that are never correct.
C)Computer models inadequately interpret the influence of the surface on the weather.
D)The distance between grid points on some models is too small to pick up storm systems.

Question 23

Which of the following describes the least accurate method of predicting the weather two days in advance during changeable weather conditions?

A)analogue method
B)trend method
C)persistence forecast
D)prediction by weather types

Question 24

Cyclone
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At which location represented by the four positions on the map would you expect to hear the following 12-hour forecast: "Cloudy and cold this morning with snow this afternoon and tonight"?

A)position 1
B)position 2
C)position 3
D)position 4

Question 25

Explain the relationship between dew point and minimum temperatures.

Question 26

Cyclone
Which of the following descriptions is associated with an omega high?

A)It does not stay in the same geographic area for long.
B)It produces high surface wind speeds.
C)It forms when the flow aloft is meridional.
D)It is known as a shallow high.

Question 27

What local signs predict the approach of a low-pressure centre or a weather front?

Question 28

Cyclone
In which direction will the storm system apparently move?

A)northeast
B)southeast
C)east
D)northwest

Question 29

List some of the ways that you can predict the future movement of surface middle-latitude cyclones.

Question 30

Which of the following statements explains the meaning of a probability forecast that calls for a "40 percent chance of rain"?

A)There will be measureable rain on 40 percent of the forecast area.
B)There is a 40 percent chance that there will be measurable rain in the forecast area.
C)There will be measurable rain during 40 percent of the time over the forecast area.
D)There is a 40 percent chance that there will be no measurable rain at any random place within the forecast area.

Question 31

In which of the following conditions can a persistence forecast be quite accurate?

A)when upper-level winds blow straight from west to east
B)when a frontal system approaches your location at constant speed
C)when the weather has been unusually cold for several days
D)when you are positioned in the middle of a large, stationary air mass
​
The following questions refer to the above illustration of a middle-latitude cyclone.The dashed lines show the positions of the fronts six hours ago.

Question 32

Which of the following forecast methods compares past weather maps and weather patterns to those of the present?

A)nowcasting
B)persistence forecast
C)analogue method
D)trend method

Question 33

When examining a surface map, which of the following factors can be used to predict the movement of a surface low-pressure area?

A)orientation of the isobars behind a cold front
B)orientation of the isobars in front of warm front
C)movement during the previous two hours
D)region of greatest pressure decrease

Question 34

Which of the following forecast methods is used to predict weather by weather types?

A)steady-state forecast
B)persistence forecast
C)analogue method
D)probability forecast

Question 35

Suppose that in the middle of January the weather is typically several degrees warmer than the rest of the month. Which of the following forecast methods would be used to predict this "January thaw" for the middle of January in the following year?

A)climatological forecast
B)persistence forecast
C)probability forecast
D)forecast based on the analogue method
​
The following questions refer to the above illustration of a middle-latitude cyclone.The dashed lines show the positions of the fronts six hours ago.

Question 36

Cyclone
At which location represented by the four positions on the map would you expect to hear the following 12-hour forecast: "Partly cloudy and continued warm through this afternoon and evening"?

A)position 1
B)position 2
C)position 3
D)position 4

Question 37

Which of the following statements describes what is required for a forecast to show skill?

A)It must be better than a forecast based on persistence or climatology.
B)It must be accurate over more than 90 percent of the forecast area.
C)It must be accurate to within 2°C of the predicted temperature.
D)It must use the analogue method of forecasting.

Question 38

Which of the following forecast methods are often used for very short-range weather forecasting?

A)steady-state forecast and pattern recognition method
B)ensemble forecast and pattern recognition method
C)analogue method and ensemble forecast
D)steady-state forecast and analogue method
The following questions refer to the above illustration of a middle-latitude cyclone.The dashed lines show the positions of the fronts six hours ago.

Question 39

Which of the following forecasting methods assumes that weather systems will continue to move in the same direction and at the same speed as they have been moving?

A)weather types forecast
B)probability forecast
C)steady-state forecast
D)climatological forecast

Question 40

Which of the following forecast methods would be used to determine the probability of a white Christmas?

A)persistence
B)climatological
C)ensemble
D)analogue

Question 41

To accurately depict a middle-latitude cyclone and to forecast the cyclone's movement, about how far apart should weather observing stations be?

Question 42

Describe the data and tools that a meteorologist assembles prior to making a weather forecast.

Question 43

List some of the factors that affect the accuracy of atmospheric models.

Question 44

Assuming you know last night's minimum temperature, what weather information can be used to predict tonight's minimum temperature?

Question 45

Explain the process of ensemble forecasting and how it is useful to meteorologists.

Question 46

Explain how observed teleconnection patterns can help in the preparation of a seasonal weather forecast.

Question 47

What type of forecast method do you think is most appropriate for the following forecasts: short range (6 to 12 hours); medium range (24 to 48 hours); long range (5 to 10 days); seasonal (3 month)?

Question 48

Discuss the strengths and weaknesses of four different types of weather forecasting methods.