Weather Flashcards
1
Q
How does the air flow in low pressure systems?
A
- Inward
- Upward
- Counterclockwise
2
Q
How does air flow in a high pressure system?
A
- Outward
- Downward
- Clockwise
3
Q
How many types of fronts are there, and what are they?
A
There are 4 front types
- Occluded Fronts
- Stationary Fronts
- Warm Fronts
- Cold Fronts
4
Q
What occurs in a occluded front?
A
A fast moving cold front catches up with a slow-moving warm front.
2 Types:
- Cold Front Occlusions
- Warm Front Occlusions
5
Q
What occurs in a stationary front?
A
Two air masses are relatively equal, the boundary/front that separates them remains stationary and influences the local weather for days.
The weather is typically a mixture of both warm and cold fronts
6
Q
What type of weather would you encounter in a cold front?
A
As the front passes expected weather can include:
1. Towering cumulus or cumulonimbus clouds
- Heavy rain accompanied by lightning, thunder and/or hail
- Tornadoes possible
- After passage:
- Good Visibility
- Cooler temperatures
7
Q
What type of weather can be expected near a warm front?
A
As the front passes expected weather can include:
1. Stratiform Clouds
- Drizzle
- Low Ceilings
- Poor Visibility
- Variable Winds
- Rise in temperature
8
Q
Associated weather with a front depends on?
A
- Amount of moisture
- Degree of stability of the air that is forced upward
- The slope of the front
- Speed of the frontal movement
- The upper wind flow
9
Q
What is a trough?
A
Areas of low atmospheric pressure. At the surface, when the low pressure converge, it can’t go outwards against the pressure, or down so it goes upward.
A low/trough is a area of rising air, and rising air is conductive to cloudiness and precipitation.
Hence the general association of low pressure and bad weather
10
Q
Low pressure is usually associated with what type of weather?
A
Bad weather
11
Q
What is a ridge?
A
An area of high atmospheric pressure (descending air), depleting the quantity of air.
Descending air dissipates clouds and precipitation, hence the general association of low pressure and bad weather.
12
Q
High pressure systems usually associated with what type of weather?
A
Good weather.
Downward air pressure gets rid of clouds and moisture, hence the association of high pressure systems, and good weather.
13
Q
Standard temperature and pressure values at sea level?
A
59f or 15c and 29.92hg or 1013.2 millibars
14
Q
What are isobars?
A
A line on a weather chart which connects areas of equal or constant barometric pressure.
15
Q
If isobars are close together on a surface weather chart or a constant pressure chart, what info will this provide?
A
The spacing of isobars on charts defines how steep or shallow a pressure gradient is.
Isobars close together indicate areas of high wind speeds.
16
Q
A steep pressure gradient (ISO bars close together) indicate what on a surface weather chart?
A
Higher wind speeds
17
Q
A shallow pressure gradient (ISO bars not close together) indicates?
A
Lower wind speeds
18
Q
Winds flow across isobars at an angle because?
A
Surface friction
19
Q
The rate of atmospheric pressure decrease with an increase in altitude?
A
1” hg / 1,000’
20
Q
What does the dew point mean?
A
The temp to which a sample of air must be cooled to attain the state of saturation
21
Q
When the temp and dew point are close together (within 5 degrees) what type of weather is likely?
A
- Visible moisture in the form of clouds, fog, dew.
- Ideal conditions for carb icing
22
Q
What determines the type and the vertical extent of clouds?
A
The stability of the atmosphere
23
Q
A stable atmosphere makes vertical movement:
A
Difficult
24
Q
Unstable atmosphere, small vertical air movements become:
A
Larger, resulting in turbulent air and convective activity
Instability can lead to significant turbulence, extensive vertical clouds, and severe weather
25
What type of clouds are associated with stable air?
Stratiform clouds
26
What type of turbulence should you expect from stable air?
Smooth
27
What type of precipitation would you get from stable air?
Steady
28
In stable air, what type of visibility would you expect?
Fair to poor
29
What types of clouds are associated with unstable air?
Cumuliform clouds
30
Turbulence expected from unstable air?
Rough
31
What type of precipitation would you expect from unstable air?
Showery
32
What kind of visibility would you get from unstable air?
Good visibility
33
When there's significant precipitation occurring at the surface, how thick can you expect the clouds to be?
- Significant precipitation requires clouds to be at least 4,000' thick
- Heavier precipitation, thicker the clouds are likely to be
34
What type of meteorological info should you be aware for icing?
1. Location of fronts: Location, type, speed and movement
2. Cloud layers: location of cloud bases and tops, which is valuable when determining if you will be able to climb above icing layers or descend beneath those layers into warmer air' refer to PIREP's and forecasts
3. Freezing levels: Important when determining how to avoid icing and how to exit icing conditions if accidentally encountered
4. Air temp and pressure: Icing tends to be found in low-pressure areas and at temps at or around freezing
35
What conditions are needed for structural icing to occur?
1. Visible moisture
2. below freezing temps at the point the moisture strikes the aircraft
36
2 main categories of icing?
Structural: Refers to the surface components
Induction: Refers to the engine's induction system
37
How can you determine where the freezing level is?
1. CIP (current icing products) & FIP (forecasting icing products)
2. Freezing level graphics charts
3. GFA tool
4. PIREP's
5. AIRMET's
6. SIGMET's
7. Surface analysis charts
8. Low-level SIGWX charts
9. Winds and Temps Aloft (for air temp at alt)
38
What is the definition of the term freezing level?
The lowest altitude in the atmosphere over a given location at which the air temp reaches 0 degrees celsius
- It's possible to have multiple freezing layers when a temp inversion occurs above the defined freezing level
39
3 Types of icing that may occur during flight
1. Rime Ice
2. Clear Ice
3. Mixed Ice
40
What's Rime icing?
Forms when drops are small (from stratiform clouds) or light drizzle freeze before they spread out over the surface
41
What is clear icing?
When a droplet hits the surface, spreads out, then freezes forming a layer of thin sheet ice over the surface
42
Mixed icing during flight
Forms when droplets vary in size when liquid droplets are mingled with snow or ice particles.
- The particles become embedded in the clear ice, building a very rough accumulation
43
Does icing change the aerodynamic of the wing?
No. It changes the smoothness of airflow over the wing, causing it to be slower airflow over the surface
44
Slowing of airflow over an iced surface is dangerous because
It causes an early airflow separation , resulting in a loss of lift. This can also prevent aircraft to become airborne at normal speeds for takeoff
45
Factors for a thunderstorm to form?
1. Sufficient water vapor
2. Unstable lapse rate
3. Lifting force to start the storm process
46
3 Stages of a thunderstorm
1. Cumulus: Updrafts cause raindrops to increase in size
2. Mature: Rain at earth's surface, if falls through, or immediately beside the updrafts
3. Dissipating: Downdrafts and rain start to dissipate
47
SIGMET's are issued for conditions affecting the area of at least:
3,000 miles
48
Non-Convective SIGMET examples:
1. Sandstorms/ Dust Storms that lower surface and flight visibility to below 3 miles
2. Volcanic ash
3. Icing not associated with thunderstorms
49
Examples of Convective SIGMET's
- Thunderstorms
- Tornadoes
- Severe Turbulence
- Hail greater than 3/4"
- Wind Gusts greater than 50 kts on the surface
50
What’s the ceiling of class D airspace?
10,000’ MSL
51
What's a ground-based temperature inversion?
- Traps fog, smoke, and other restrictions into low levels of atmosphere. The air is stable, with little or no turbulence
52
What is a temperature inversion?
An inversion is an increase in temperature with height, as opposed to the normal decrease with height
53
Temperature inversions are associated with what type of air?
Stable air
54
What kind of turbulence is to be expected with temperature inversions?
little to none
55
How does fog form?
Cooling air beyond its dewpoint (creating radiation, advection, or upslope fog)
or
Adding moisture to the air and elevating the dewpoint
(producing frontal fog, or steam fog)
56
Types of Fog:
1. Radiation
2. Advection
3. Upslope
4. Precipitation
5. Steam
57
How does radiation fog form?
Ground cools the adjacent air to the dew point on calm, clear nights
58
Advection fog forms:
- Warm moist air is blown over a cooler surface
- 15 KTS of wind will make this thicker
- Stronger winds will lift fog into low stratus clouds
59
Steam Fog Forms:
When dry air moves over warm water, the water conducts warm moist air into the cool air above and creates thick steam fog
60
Upslope fog forms:
Stable air is being cooled as it moves up sloping terrain
- Once the upslope wind ceases the fog dissipates
- Upslope fog is dense and extends to high altitudes
61
Define wind shear:
Wind shear is the rate of change of wind velocity (direction and/or speed)
62
What 3 areas should be of concern to a pilot for wind shear?
1. Low-level temperature inversions
2. Frontal zones or thunderstorm
3. Clear air turbulence (CAT) at high levels associated with a jet stream or strong circulation
63
Why is wind shear an operational concern to pilots?
- Unexpected changes in wind speed and direction can be potentially very hazardous to aircraft operations at low altitudes on approach to and departing from airports
64
Where can I examine if wind shear might affect my flight?
1. Terminal Forecasts
2. METAR's
3. SIGMET's, Convective SIGMET's, severe weather watch reports
4. LLWAS (low level windshear alert system)
5. PIREP's
65
What are the different types of AIRMET's?
1. Sierra: Describes IFR conditions and mountain obscuration
2. Tango: Describes moderate turbulence, sustained winds of 30 kts or greater, and or non-convective LLWS
3. Zulu: Describes moderate icing, and freezing level heights
66
Sierra AIRMET's
Tell you IFR conditions and mountain obscurations
67
Zulu AIRMET's
- Icing and freezing level altitudes
- Areas of multiple freezing levels
68
Tango AIRMET's
- Surface winds greater than 30 kts
- Moderate turbulence
- Non-convective LLWS (low level wind shear)
69
Can I use 3rd party vendors to satisfy the preflight action required by 14 CFR 91.103?
Yes, but you should be aware that they are not held to the standard of the FAA, or NWS quality control standards. If in doubt about weather information consult with FAA Flight Service Specialist
70
Information that should be included in a weather briefing?
1. Adverse conditions
2. VFR flight not recommended
3. Current conditions
4. Enroute forecast
5. Dest. Forecast
6. Winds Aloft
7. NOTAMS
8. NWKRAFT
9. TFR's, SUA's, MOA's MTR's
71
What are the two types of METAR's?
1. Routine METAR's given every hour
2. Aviation Special Weather Report: Given to update a METAR for rapidly changing weather conditions, aircraft mishaps, or other critical info.
72
Types of weather briefing available from an AFSS/FSS briefer?
1. Standard: Request when planning a flight and have not received a brief before this
2. Abbreviated: Request when needed to supplement mass disseminated data, update a previous brief, or when you need 1-2 items.
3. Outlook: Request when flight is more than 6 hours out from the time of the briefing.
73
"Obs/Warn" tab on GFA tool shows?
Observation and warnings
1. METAR
2. PCP/WX (Precipitation and Weather)
3. CIG/VIS (Ceiling and Visibility)
4. PIREP (Pilot Reports)
5. RAD/SAT (Radar and Satellite)
74
How does the GFA tool present turbulence information?
- LO: Showing turbulence below FL180
and
- HI: Showing turbulence at or above 18,000' MSL
75
What info does the "forecast" tab of the GFA tool allow us to see?
1. Terminal Aerodrome Forecast (TAF)
2. Ceiling and Visibility (CIG/VIS)
3. Clouds
4. Precipitation/Weather (PCPN/WX)
5. Winds
6. Turbulence (Turb)
7. Thunderstorms (TS)
8. Ice
76
What does PCPN/WX stand for?
Precipitation and Weather
77
Obs/Warn stands for?
Observation and warnings
- A tab found on the GFA tool to find:
1. METAR's
2. PCPN/WX
3. CIG/VIS
4. PIREP
5. RAD/SAT
78
4 types of inflight weather aviation weather advisories?
1. SIGMET's (WS)
2. Convective SIGMET's (WST)
3. AIRMET (WA; or text graphical product)
4. Center Weather Advisory (CWA)
79
What is an AIRMET?
Advisories of significant weather that doesn't require the issuance of a SIGMET.
- It's intended for use by all pilots in the preflight and enroute phase of flight to enhance safety
80
How many ways are AIRMET's issued?
1. Text bulletins (WA)
2. Graphics (G-AIRMET)
81
How often are AIRMET's issued?
Every 6 hours
82
AIRMET's contain details about?
- IFR
- Extensive mountain obscuration
- Turbulence
- Strong Surface Winds
- Icing and freezing levels
83
Winds aloft forecasts do not issue winds for what altitudes?
Not issued for altitudes within 1,500' of a locations elevation
84
Winds aloft forecast always show negative until what altitude? (because all temps are negative above this altitude)
24,000' MSL
85
Winds aloft forecast don't show temperatures for what altitude?
2,500' of a location's elevation
86
Winds displayed in winds aloft forecast are in relation to true or magnetic north?
True
87
9900 on a Winds aloft forecast indicates?
Less than 5 kts / light and variable
88
How can you avoid turbulence using the winds aloft forecast?
Avoid altitudes with large changes in wind direction
89
Winds aloft forecast can provide what valuable information?
1. Most favorable altitude: If looking for tailwind based on direction of flight
2. Areas of possible icing - by noting air temps of +2 degrees celsius to -20 celsius
3. Temperature inversions
4. Turbulence: By observing abrupt changes in wind direction and speed at different altitudes
90
Examples of various NWS charts you used during preflight planning?
1. Surface analysis charts
2. Short-range surface prog charts
3. SIGWX prog chart
4. Convective Outlook chart
5. Freezing level graphics
91
Surface Analysis Charts show you what?
- ISO bars
- Position of highs and lows
- Troughs and ridges
- Boundaries and fronts
92
Describe a CVA (ceiling and visibility) chart?
CVA is a real-time analysis updated every 5 min of current ceiling and visibility conditions across the US
- It's intended to provide situational awareness for the area.
93
LIFR
Low IFR
- Ceiling less than 500' and/or visibility below 1 mile
94
IFR Conditions
- Ceiling less than 500'- 1000'
- Visibility is 1-3 miles visibility
95
Marginal VFR weather
- 1,000' - 3,000' ceilings
- 3-5 Mile Visibility
96
VFR weather
- Greater than 3,000' ceilings
- Greater than 5 miles visibility
97
What do surface prog charts show you?
A snapshot of surface pressure systems, fronts, and precipitation for a 2-1/2 day period
- i.e fronts, pressure systems, troughs, ridges etc.
98
Surface prog charts are divided into how many forecast periods?
5 (12, 18, 24, 48 and 60hr periods)
99
What charts can I find Iso bars on?
Surface prog charts show iso bars
100
How does advection fog form?
- When warm, moist air, moves over a colder surface
101
Low-level SIGWX shows weather hazards from what altitude range?
FL240 and below
102
How often are low-level SIGWX prog charts issued?
- 4x a day in two types 12 hr prog chart and 24hr prog chart
103
High-Level SIGWX prog charts are used for?
- Range of flight levels from FL250 to FL630
- Used by airline dispatchers for flight planning and weather briefing before departure and by flight crew during flight
104
Convective outlook chart defines what type of activity?
It defines areas of severe activity based on probability
(MRGL, SLGT, ENH, MDT, HIGH, TSTMS)
105
What weather tool would employ you to make a go/no go decision?
SIGMET’s because they’re severe weather that I may not have experienced before and may be dangerous for flight operations.
106
In order to receive special VFR clearance, what requirements do you need during the day and night?
Daytime:
- 1 SM ground visibility
- ATC clearance
- Remain clear of clouds
Night
- IFR rated
- Aircraft has to be IFR equipped
107
VFR cruising altitudes are based on magnetic or true course?
- Magnetic
- 0-179 Odd thousands plus 500'
- 180-359 Even thousands plus 500'
108
Minimum equipment needed for operations in class A airspace?
- IFR equipped
- 2 way radio
- Transponder
- ADSB-Out
109
What are class B airspace minimum equipment needed for operation?
- 2 way radio
- Transponder w/ altitude reporting capability
- ADSB-Out
110
Class C airspace minimum equipment needed for operation within the airspace?
- Mode C Transponder
- ADSB-Out
- 2 way radio
111
What minimum equipment needed for operation in class D airspace?
- 2 way radio
112
What airspace does NOT have a minimum license requirement operation within it's airspace?
- Class C
- Class D
- Class E
- Class G
113
To operate in class A airspace, what minimum license is required for a pilot to have?
The pilot must be:
1. Private Pilot
2. Instrument Rated
114
How is class A charted on a sectional map?
It is not charted on a sectional chart
115
What basic ATC services are provided to all aircraft operating within class B airspace?
- VFR pilots will be provided sequencing and separation from other aircraft while operating in B airspace
116
Minimum pilot certification to operate an aircraft within Class B airspace?
- Private Pilot Certificate
- PIC holds a Recreational Pilot Certificate and has met requirements of 14 CFR 61.101 or for a student pilot seeking a recreational pilot certificate meet requirements of Part 61.94
- PIC who holds a Sport Pilot Certificate who meets qualifications same as above
- Student Pilot who has met the requirements of Part 61.94 or Part 61.95 (endorsement in logbook stating Student is proficient in operating an aircraft in B airspace)
117
What requirements are needed in order to enter class B airspace?
- Clearance from the ATC who has controlling authority over the area
118
Floor and ceilings of class C airspace?
- SFC to 4,000 above airport elevation in
119
Basic dimensions of class C airspace:
- 5NM radius from main airport : SFC - 4000'
- 10NM radius shelf 1,200' above airport to 4,000'
-
120
What is the Mode C veil?
It's the radius extending 30NM from the main airport in a class B airspace
- It requires at minimum a mode C transponder in this area
121
Minimum pilot certificate to operate an aircraft within class C airspace?
- A student pilot certificate
122
Equipment required for Class C airspace:
- 2 way radio
- Pressure altitude reporting equipment w/ Mode C capability
- ADS-B out equipment
123
When departing a satellite airport without an operative control tower located within class C airspace, what requirement must be met?
- Establish and maintain 2 way radio comms with ATC facilities having jurisdiction over the Class C airspace as soon as practicable after departing
124
FLUNKN on a PIREP is:
Flight level unknown
125
What's the difference between a METAR and a TAF?
METAR: Current weather at the time it was taken at the time
TAF: Forecast of weather that will happen
126
What is the difference between AIRMET's and SIGMET's?
AIRMET: Significant weather that may affect smaller general aviation aircraft (i.e. high winds)
SIGMET: Significant weather that would be of interest of larger airliner aircrafts (i.e. high wind w/ sandstorms, thunderstorms etc.)
127
Is air more or less dense at higher altitudes?
Less dense = poor aircraft performance
128
What is a limitation with charts used for calculations in the POH?
The charts were designed for an aircraft that was fresh out of the factory without all equipment installed. It is not 100% accurate so use conservative figures.
129
At airports located at higher altitudes, what should you do to your aircraft before taking off?
You should lean the mixture at full-power to get a better performance out of your engine for climing out of the area
130
If outside air temperature at a given altitude is warmer than standard, the density altitude is:
Higher than pressure altitude
131
As the outside air temperature (OAT) increases does the air becomes more or less dense?
less dense; and result in higher air density altitude (i.e. molecules spread out more)
132
When is density altitude and pressure altitude the same?
When the temperature is at the standard (15c or 59f)
133
An increase in density altitude means what type of performance for your aircraft?
Molecules are spread further apart, and the aircraft won't perform as well than it would at a lower altitude
134
As an aircraft climbs to a higher altitude, it results in an ______ in density altitude.
increase
- Meaning your aircraft performs worse the higher you climb
135
A decrease in pressure (lowering the barometric scale on altimeter) causes an ________ in density altitude.
increase
- The decrease in pressure is the spreading out of molecules, resulting in an increase in density altitude (performance is that of a higher true altitude)
136
Higher temperatures create ______ pressure air.
lower
- The air is heated and molecules spread apart
137
Pressure altitude is true altitude corrected for __________
non-standard pressure (when you set 29.92 at the altimeter)
138
Density altitude is "pressure altitude" corrected for ______
non-standard temperature
139
An increase in temperature results in an ________ in density altitude.
increase
140
Higher temperatures (increase in temperature) does what to an air mass?
It creates lower pressure air (air molecules spread out, therefore pressure is lower in the atmosphere)
141
An decrease in temperature does what to an air mass?
It increases air pressure
- Air molecules are tightly packed together and your result is a decrease in density altitude
142
Wind flows across barriers in layers, and terrain can interrupt the flow of air creating:
- Mountain wave turbulence
143
When traveling across mountains, winds in excess of 40 kts over the crest of the mountain can create turbulence how far out?
- 100 miles downwind, and create wave interruption higher than highest peak
144
Below the crest of rotary clouds can be dangerous because:
- There are pockets of air that can flip you over
145
If you come across rotary clouds, you can expect:
- Areas of lift on one side
- Areas of sink on the other
146
When planning of flying over mountainous areas, the FAA suggests:
- If planned altitude of flying has winds excess of 30 kts, small aircraft should not attempt to fly over mountain areas
147
What steps to take when planning flight through mountain:
1. Fly 3,000' - 5,000' above peaks
2. Climb to selected altitude while still 100 miles from mountain range
3. Approach ridge at 45 degree to promote safer retreat if turbulence becomes too severe
148
How often are surface analysis charts issued?
Every 3 hrs
149
Are prognostic charts an observation or a forecast? and what is the difference?
Prognostic charts are a forecast
The difference is that a forecast is what is assumed to be the weather, and an observation is what is currently going on.
150
Prog charts are issued for what time intervals? and How often are they issued?
- 12 & 24 hrs: Every 4 hrs
- 36, 48 & 60 hrs: 2x daily
- 3-7 day forecast is issued once daily 1400Z w/ a valid time at 1200Z
151
How long are sigmets valid for?
- Valid for 4 hours
- Convective SIGMET are valid for 6 hours
152
SIGMETS report severe weather such as:
- Severe icing not associated with thunderstorms
- Severe or extreme turbulence or clear air turbulence (CAT) not associated w/ thunderstorms
- Dust storms / sandstorms that lower surface or in-flight visibility to below 3 miles
- Volcanic ash
153
How long are convective SIGMETS valid for?
- Valid for 2 hours
154
What kind of weather can be expected from a convective SIGMET?
- Severe thunderstorms w/ surface winds greater than 50 knots
- Hail at the surface greater than or equal to 3/4" in diameter
- Tornadoes
- Embedded thunderstorms, lines of thunderstorms, w/ heavy or greater precipitation that affect 40% or more of a 3,000 sq mile or greater region
155
How often are TAF's issued and how long are they good for?
- 4x daily
- Good for 24 or 30 hours depending on the location
156
What are SLD? And what threats do they have to pilots in flight?
- Supercooled Liquid Droplets, and they're water droplets that have been cooled to 0°c but still remain in a liquid state
- When these droplets make impact they can form large sheets of ice quickly and reduce airplane performance
