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CDC URE > 5B-2 Fcst Sfc Wx Elements and Flt Wx Elements > Flashcards

5B-2 Fcst Sfc Wx Elements and Flt Wx Elements Flashcards

0
Q

What changes of state absorb heat from the surrounding environment?

A

Vaporization, fusion, and sublimation

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1
Q

Which term defines a change in state from a solid to a gas?

A

Sublimation

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2
Q

What is the most efficient method of cloud droplet growth?

A

Collision and coalescence

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3
Q

What term is used to define the process where the outer edge of the cloud mixes with air outside of the cloud?

A

Dry-air entrainment

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4
Q

Which cloud forecasting tool is biased towards climatology (average conditions), and may not be accurate during abnormal conditions?

A

Model output statistics

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5
Q

What is the main difference in forecasting the occurrence of convective or cumuliform clouds versus stratus clouds?

A

Atmospheric stability

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6
Q

You would NOT expect stratus clouds to form when

A

The curvature is anticylonic
Form when warm stable air is being lifted over a warm front
Onshore winds are in an area of cyclonically curved contours
Large area of slight convergence has cyclonically curved contours

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7
Q

A very narrow band of clouds associated with a cold front may indicate the

A

700 mb contours are perpendicular to the surface cold front

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8
Q

The type and intensity of precipitation observed at the earth’s surface is related to the thickness of the cloud aloft, and particularly to the

A

Temperatures in the upper part of the cloud

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9
Q

With a quasistationary front in the southern US under a broad west or southwest flow aloft and a weak surface low, the snow rain zone becomes

A

Elongated in the direction of the upper-level current with precipitation rates stretching over long periods

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10
Q

Which condition increases the probability of fog formation?

A

Advection a warm, moist air mass over a cold surface

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11
Q

Which condition decreases the likelihood of fog formation?

A

Increased temperature and decreased moisture content

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12
Q

What type of air mass causes a persistent type of continental high-inversion fog to occur in valleys?

A

Maritime Polar air

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13
Q

Which visibility restriction is the MOST localized?

A

Smoke

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14
Q

What would the estimated low-level wind speed be, in knots, from satellite imagery displaying arc shaped open-cell cumulus clouds?

A

21 to 30

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15
Q

If no inversion is present, forecast the maximum surface wind gusts to be

A

80 percent of the 5,000 foot wind speed

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16
Q

In forecasting frontal winds, the deepening or filling of a frontal trough

A

Increases or decreases the winds

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17
Q

Which tertiary circulation is associated with mountain-wave turbulence?

A

Foehn wind

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18
Q

Object A has a temperature of 49 degrees C, object B has a temperature of 65C, and object C has a temperature of 88C. How. It thermal energy be transferred between the three objects?

A

B and C transfer to A

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19
Q

How many degrees are there between the freezing point and the boiling point on the Kelvin temperature scale?

A

100

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20
Q

What type humidity is another expression of mixing ratio?

A

Absolute

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21
Q

Which forecasting tool provides a summary of monthly and annual climatic data for a station?

A

Operational Climatic Data Summary (OCDS)

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22
Q

Surface heating occurs more rapidly

A

With a stable lapse rate

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23
Q

A heat wave over the Midwestern and eastern part of the US develops when

A

Long-wave trough stagnates over the Rockies and a long-wave ridge lays over the east coast

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24
Q

Which condition must exist for the development of a cold wave over the US?

A

Movement of a low eastward from the Continental Divide

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25
Q

How many hours can the GFS long range forecast predict out?

A

384 hours

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26
Q

If the temperature through a vertical column is warmer than standard, then the air density is

A

Less than standard and a pilot must fly higher to reach a given indicated altitude

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27
Q

How is the difference (D) value calculated?

A

True altitude minus standard altitude

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28
Q

What values do you need to compute the pressure altitude?

A

Field elevation and altimeter setting

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29
Q

Density altitude is the

A

Altitude at which a given density is found in the standard atmosphere

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30
Q

What two parameters are used to compute density altitude?

A

Pressure and virtual temperature

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31
Q

Turbulence should NOT be anticipated in areas of

A

Inflow in a digging jet

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32
Q

As a GENERAL rule, the effects of turbulence for a fixed-wing aircraft are increased with decreased

A

Weight of the aircraft

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33
Q

Roll or rotor clouds form

A

Parallel to the mountain ridge and are located on the leeside

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34
Q

The MOST dangerous features of mountain wave clouds are the turbulence in the cap and

A

Rotor cloud

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35
Q

All turbulence not thermally induced/associated with convective activity is classified as

A

Clear-air

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36
Q

How can aircrew avoid the effects of wake turbulence?

A

Land beyond the touchdown point of a leading aircraft, lift off ahead of the liftoff point of a leading aircraft, and fly above leading aircraft

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37
Q

Which type of aircraft icing occurs in cumuliform clouds and is hard, glossy and heavy?

A

Clear

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38
Q

What is the intensity for in-flight icing when deicing or anti-icing equipment fails to reduce or control the hazard and immediate diversion is necessary?

A

Severe

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39
Q

How does in-flight icing on an airplane effect drag and the ability to lift when considering airfoil, respectively?

A

Increases; decreases

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40
Q

Which ice protection system is activated BEFORE the aircraft enters the icing condition?

A

Anti-icing equipment

41
Q

What icing intensity corresponds to freezing drizzle?

A

Moderate

42
Q

Which item is NOT a guidance tool or product for icing?

A

METSAT

43
Q

What type icing, if any, will an aircraft encounter if icing conditions are favorable and flying above 12,000 ft in a stratiform cloud?

A

Rime

44
Q

With a frontal system, the greatest icing occurs when up drafts exist. The only exception to this rule is when icing is associated with

A

Freezing precipitation

45
Q

How would ab aircraft be affected during landing if it were flying from a headwind over the outer marker to a tailwind over the runway?

A

Indicated airspeed decreases, and aircraft drops below the glide slope

46
Q

How does the upper portion of a thunderstorm gust front compare to the surface portion?

A

Precedes the surface portion by one or two miles

47
Q

When forecasting weather you would expect low-level wind shear when

A

Sustained surface wind is less than 10 knots and the absolute value of the vector difference between the gradient wind and the surface wind is 30 knots or greater and an inversion or isothermal layer is present below 2,000 ft

48
Q

The combination of cold air aloft and warm surface air can produce a

A

Sharp lapse rate and an unstable atmosphere

49
Q

In the continental US, what months of the year are the best for thunderstorm activity?

A

March thru September

50
Q

What are the conditions necessary for the development of tornadoes, severe thunderstorms, and their associated destructive phenomena?

A

Unstable atmosphere, large quantities of moisture, strong mid-level winds, surface-based lifting mechanism, and a favorable WBZ

51
Q

What kind of thunderstorm is the closest to a three-stage, non-severe thunderstorm?

A

Air-mass

52
Q

What stage of a non-severe thunderstorm occurs when precipitation is suspended aloft?

A

Cumulus

53
Q

Hail size is dependent on the

A

Strength of the updraft core and the length of fall from the freezing level to the surface

54
Q

Thunderstorms that appear to move to the right of mid-level winds are called

A

Discrete propagation

55
Q

Which action is associated with the gust front?

A

Forward flank downdraft

56
Q

Super cells splitting into two separate cells is caused by the environmental wake flow “cutting” into the updraft on the

A

Downwind side of the updraft core and precipitation “loading” in the mid levels above the updraft core

57
Q

What JS the one requirement that must ALWAYS be present in order for tornadoes to form?

A

Appreciable lifting

58
Q

In what tornado-producing air structure do tornadoes most frequently occur in families, with paths that are commonly long and wide?

A

Type 1, Great Plains

59
Q

What is the most common severe weather phenomenon associated with the Type E, major cyclone severe weather producing synoptic pattern?

A

Hail

60
Q

Where does one of the two well-defined northwest flow frequency axes extend?

A

Central Missouri to New England

61
Q

What type of destructive summertime mesoscale system is associated with northwest flow outbreaks?

A

Derecho

62
Q

On the average, how many hours elapse between the first thunderstorm development of a mesoscale convective complex and the time it begins to decay?

A

16 1/2 hours

63
Q

What upper-level (500 millibars to 200mb) zone pattern is extremely important to identify over a mesoscale convection complex genesis region?

A

Difluence

64
Q

What is the peak month for haboob dust storms to occur based on climatology?

A

June

65
Q

What are the two primary concerns when forecasting a haboob dust storm?

A

Visibility and wind speed

66
Q

The typical hurricane season extends from

A

June through November

67
Q

A fairly accurate sign of an approaching tropical cyclone is

A

A swell that comes in a series of waves with a long interval between crests

68
Q

The difference between the actual sea surface elevation and the predicted astronomical sea surface elevation is know as the

A

Storm surge

69
Q

Warm advection in the lower levels during snow-producing situations

A

Can suggest increased snow potential

70
Q

What direction and speed does a non-occluding baroclinic low that produces heavy snow usually move?

A

East-northeast at approximately 25 kts or greater

71
Q

A severe blizzard contains winds

A

GTE 50 kts and temperatures LTE 10F

72
Q

When forecasting precipitation type, the layer between the surface and what millibar level is the determining factor in terms if temperature-moisture advection?

A

700mb

73
Q

What is the threshold value, in knots, for strong non-convective winds?

A

GT 34 kts

74
Q

What is the primary concern when forecasting shamals?

A

Source region

75
Q

Why does the isobar spacing on a skew-t chart increSe from the bottom to the top of the chart?

A

Accounts for the decrease in density of the atmosphere with height

76
Q

Potential temperature is the temperature an air sample would have if it’s pressure were increased to

A

1,000 mb in a dry adiabatic process

77
Q

The lifted condensation level is the intersection obtained on the skew-t chart between the

A

Mixing ratio line and dry adiabat

78
Q

A second method for finding the convective condensation level was developed to give increased accuracy in

A

Severe weather forecasting

79
Q

To determine the mixing condensation level, you must first determine the

A

Top of the mixing level

80
Q

Convective temperature is the temperature that surface air must reach to initiate convective currents that will

A

Extend high enough for the air to become saturated

81
Q

What temperature can be obtained by following a dry adiabat air parcel down from the convective condensation level to the point where the dry adiabat air parcel intersects the isobar representing the surface pressure?

A

Convective

82
Q

The height at which a parcel of air that is lifted, first becomes warmer (less dense) than the environment is the

A

Level of free convection

83
Q

What indicates a temperature increase with an increase in height indicating a negative lapse rate in a layer of the atmosphere?

A

Inversion

84
Q

What is the potential for thunderstorms with a convective available potential energy (CAPE) of 2250 joule per kilogram (J/kg)?

A

Moderate

85
Q

What would be the likely coverage and intensity of thunderstorms with a cross total of 30 and a vertical total of 23?

A

Scattered severe

86
Q

Tornado occurrences are grouped in severe weather threat index values of

A

Greater than 400

87
Q

The K-index is a measure of a thunderstorm’s

A

Potential

88
Q

What index is used to assess the instability of the 850 mb parcel?

A

Showalter stability

89
Q

The season of maximum hail occurrences coincides with

A

The season of maximum thunderstorms

90
Q

What percentage of hail occurrences in flight is attributed to have happened under overhanging clouds between 10,000 and 20,000 ft?

A

85%

91
Q

What is the cloud depth ratio if the convective condensation level is at 770 mb, the freezing level at 550 mb, and the equilibrium level at 270 mb?

A

0.44
(770-550)/(770-270)
(CCL-Freeze Level)/(CCL-EL)

92
Q

What is considered the optimum WBZ height, in feet, above the terrain for hail?

A

8,000 ft

93
Q

What must be determined as the first step in forecasting the size of hail?

A

Convective condensation level

94
Q

In using the T1 method of forecasting maximum wind gusts, the warmest point on the inversion is used to determine the T1 if surface convection does not dissipate the inversion and if that warmest point is within how many mb of the surface?

A

150 to 200

95
Q

What preconditions must exist to make the T2 method over forecast maximum gusts?

A

The thunderstorm must pass over the forecast point and moderate to heavy rain must occur

96
Q

A veering wind in the vertical suggests a

A

Warm air advection not associated with a warm front

97
Q

When forecasting turbulence in convective clouds below 9,000 ft what determines the severity of the turbulence?

A

Temperature difference between the moist adiabat and the free-air temperature curve

98
Q

When forecasting turbulence in convective clouds above 9,000 ft, where is the central portion of the most turbulent area?

A

Where the maximum temperature difference between the moist adiabat and the free-air temperature is.

99
Q

In severe weather forecasting, the best time period to forecast a skew-t sounding is during the

A

Maximum heating

CDC URE (9 decks)

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