Deck 13: Weather Forecasting

Question 1

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 some future time.
E) another name for a probability forecast.

Answer 1

D

Question 2

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.

Answer 2

D

Question 3

A weather warning 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.

Answer 3

B

Question 4

The forecasting technique that produces several versions of a forecast model,each beginning with slightly different weather information to reflect errors in the measurements,is called

A) climatology forecasting.
B) redundancy analysis.
C) persistence forecasting.
D) ensemble forecasting.
E) probability forecasting.

Question 5

For a forecast to show skill it must

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

Question 6

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

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

Question 7

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

A) nowcasting.
B) extrapolation.
C) first order forecast.
D) linear forecast.

Question 8

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.

Question 9

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 analogue method.
B) persistence forecast.
C) forecast based on weather types.
D) probability forecast.
E) climatological forecast.

Question 10

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

A) persistence forecasting.
B) the analogue method.
C) the trend method.
D) nowcasting.

Question 11

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.

Question 12

An analysis is

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

Question 13

An accurate forecast

A) always shows skill.
B) may or may not show skill.
C) never shows skill.
D) requires complex computer equipment.

Question 14

A persistence forecast could be quite accurate when

A) a frontal system approaches your location at 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.

Question 15

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 analogue method.
E) an extended weather forecast.

Question 16

By examining a surface map,the movement of a surface low pressure area can be predicted based upon the

A) orientation of the isobars in the warm sector.
B) region of greatest pressure decrease.
C) movement during the previous 6 hours.
D) all of the above

Question 17

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

A) Computer forecast models make assumptions about the atmosphere that are not always correct.
B) There are regions of the world where only space observations are available.
C) Computer models do not always adequately interpret the surface's influence on the weather.
D) The distance between grid points on some models is too large to pick up smaller-scale weather features such as thunderstorms.
E) all of the above

Question 18

Suppose it is warm and raining,and a cold front is moving toward your location.Directly behind the cold front,it is cold and snowing.Still further behind the front,the weather is cold and clearing.If the front is scheduled to pass your area in 6 hours,a persistence forecast for your area for 12 hours from now would be

A) cold and snowing.
B) cold and clearing.
C) cold and cloudy.
D) warm and raining.
E) not enough information on which to base a forecast

Question 19

Predicting the weather by weather types employs which forecasting method?

A) probability
B) steady-state
C) analogue
D) persistence
E) guess

Question 20

The least accurate forecast method of predicting the weather two days into the future during changeable weather conditions is usually the

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

Question 21

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

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

Question 22

Exhibit 13-1Use the following illustration of a middle latitude cyclone.The dashed lines show the positions of the fronts 6 hours ago.
Refer to Exhibit 13-1.At which of the 4 positions would you expect to hear the following 12-hour forecast: "Partly cloudy and continued warm through this afternoon and evening"?

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

Question 23

Very short-range forecasts often utilize which of the following forecast methods?

A) steady-state or trend method
B) pattern recognition method
C) ensemble method
D) both steady-state (trend method)and ensemble method
E) both steady-state (trend method)and pattern recognition method

Question 24

Lines connecting points of equal pressure change are called

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

Question 25

Exhibit 13-1Use the following illustration of a middle latitude cyclone.The dashed lines show the positions of the fronts 6 hours ago.
Refer to Exhibit 13-1.At which of the 4 positions would you expect to hear the following 12-hour forecast: "Clearing and colder today with continued rising pressures"?

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

Question 26

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) tornado warning
B) hurricane warning
C) snow advisory
D) blizzard warning

Question 27

Exhibit 13-1Use the following illustration of a middle latitude cyclone.The dashed lines show the positions of the fronts 6 hours ago.
Refer to Exhibit 13-1.At which of the 4 positions would you expect to hear the following 12-hour forecast: "Cloudy with possible showers today,turning colder by tonight"?

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

Question 28

Exhibit 13-1Use the following illustration of a middle latitude cyclone.The dashed lines show the positions of the fronts 6 hours ago.
Refer to Exhibit 13-1.The storm system will apparently move toward the

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

Question 29

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) none of the above

Question 30

A wind that changes direction in a counterclockwise sense with increasing height is called a(n)

A) backing wind.
B) Ekman spiral.
C) meridional wind.
D) veering wind.

Question 31

Automated Surface Observing Systems (ASOS)measure

A) wind speed and direction.
B) temperature and dew point.
C) air pressure.
D) all of the above

Question 32

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 33

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

Question 34

Exhibit 13-1Use the following illustration of a middle latitude cyclone.The dashed lines show the positions of the fronts 6 hours ago.
Refer to Exhibit 13-1.At which of the 4 positions would you expect to hear the following 12-hour forecast: "Cloudy and cold this morning with snow this afternoon and tonight"?

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

Question 35

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 36

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 temperature 6 to 10 days into the future.

Question 37

The forecasting of weather by a computer is known as

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

Question 38

Which below is not 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.

Question 39

When making a forecast,a meteorologist typically examines

A) surface charts.
B) upper-air charts.
C) radar displays.
D) satellite imagery.
E) all of the above

Question 40

The National Weather Service system of watches,warnings,and advisories generally don't address weather conditions which limit visibility.

Question 41

Warm advection occurs when

A) the wind veers (changes direction in a clockwise manner)with height.
B) the wind backs (changes direction in a counterclockwise manner)with height.
C) the isotherms are parallel to the winds.
D) the wind veers with height and the isotherms are parallel to the winds.

Question 42

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

Question 43

A blocking high is

A) a high pressure system and accompanying ridge that changes location quickly.
B) a high pressure system and accompanying ridge that persists in the same location for many days.
C) a high pressure system and accompanying ridge that produces torrential rains.

Question 44

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

Question 45

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

Question 46

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

A) flaws in the computer models
B) errors that creep in along model boundaries
C) sparseness of meteorological data
D) inadequate representation of pertinent meteorological processes
E) all of the above

Question 47

Describe four different types of weather forecasting methods and give an example of each.

Question 48

Suppose a large anticyclone covered the eastern United States.What do you think the corresponding 500-mb chart would look like? Why?

Question 49

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) analogue method
C) steady-state forecast
D) ensemble forecast

Question 50

About how far apart do you think weather observing stations should be in order to accurately depict a middle latitude storm and to be able to forecast the storm's movement?

Question 51

Which of the following is not 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.

Question 52

With all other factors being equal,will a cloudy day have a higher or lower maximum temperature then a clear day? How about the minimum temperature during a cloudy vs.clear night? Explain.

Question 53

A long-range forecast is a forecast that extends beyond about

A) 8.5 years.
B) 8.5 months.
C) 8.5 weeks.
D) 8.5 days.

Question 54

____________ tend to steer the movement of surface pressure systems.

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

Question 55

What local signs would you look for to predict the approach of a low pressure center or a weather front?

Question 56

A forecast of "chance of precipitation" means

A) the probability of precipitation is between 0 and 20 percent.
B) the probability of precipitation is between 30 and 50 percent.
C) the probability of precipitation is between 60 and 70 percent.
D) the probability of precipitation is greater than 80 percent.
E) none of the above

Question 57

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

Question 58

What type of forecast method do you think would be most appropriate for a short range (6 to 12 hours),a medium range (24 to 48 hours),a long range (5 to 10 days),or a seasonal (3 month)forecast?

Question 59

Why do clouds tend to reduce temperatures during the day but increase temperatures at night?

Question 60

Thickness charts help forecasters

A) identify air masses.
B) locate fronts.
C) predict daily maximum and minimum temperatures.
D) predict whether falling precipitation will be rain or snow.
E) all of the above

Question 61

Describe the relationship between dew point and minimum temperatures.

Question 62

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

Question 63

Assuming you know last night's minimum temperature,what weather information would you use to predict tonight's minimum temperature?

Question 64

Describe the difference between persistence and steady-state forecasts.

Question 65

What are some of the ways that Doppler radar can be used in weather forecasting?