Section 3: Weather Information Flashcards
1
Q
What is a METAR? How often are they issued and how long are they valid for?
A
An observation of CURRENT surface weather; issued hourly and is valid until next issuance.
2
Q
What is a SPECI? How long are they valid for?
A
Special Weather Report (SPECI): special issuance, valid until next issuance
3
Q
What is a TAF? How often are they issued and how long are they valid for?
A
forecasted weather within a 5nm radius from the airport; issued every 6 hours (4 times a day), and is valid 24-30 hours.
4
Q
What is a surface analysis chart and what does it SHOW?
A
A chart of the current surface weather.
It shows:
1. areas of high and low pressure
2. fronts
3. temperatures (in degrees F) and dew-points
5. wind directions and speeds
6. visual obstructions
5
Q
How often are surface analysis charts issued and how long are they valid for?
A
Issued every 3 hours; valid at observation
6
Q
What is a radar summary chart? How often are they issued?
A
Weather product derived from the national radar network that graphically displays a summary of radar weather reports; issued HOURLY as a summary
7
Q
What does a low-level prognostic chart show? How long are they valid for?
A
combines forecasts of fronts, isobars, and high/low pressure systems; valid at time on chart
8
Q
What does a winds and temperatures aloft chart show?
A
shows wind speed/direction and temperature at different altitudes. (winds are not reported at levels within 1500 feet of location’s elevation; temp forecasts not reported for levels within 2500 feet of location’s elevation)
9
Q
How often is a winds and temperatures aloft chart issued and how long is it valid for?
A
- Issued every 4 hours
- Valid for either 6,12, or 24 hours
10
Q
What are troughs?
A
Elongated areas of low pressure
11
Q
What is an advisory circular and where can you find these?
A
Advisory material the FAA sends out, and they can go into depth about types of weather. You can find them online and look up any type of AC you need (ex: thunderstorms)
12
Q
What do you get in a standard weather briefing?
A
TAFs, METARs, Winds and Temps Aloft, Surface Analysis Chart, Prognosis Chart, NOTAMs and TFRs (temporary flight restrictions)
13
Q
Where can you find METARs and TAFs?
A
Foreflight, Aviationweather.gov, or by texting 358-782
14
Q
What are PIREPs and how do they report about wind shear?
A
PIREPs are pilot reports submitted to the FSS, depicting real time weather conditions.
Report about wind-shear as a loss/gain in altitude/airspeed
15
Q
What is a Weather Depiction Chart and how often are they issued, as well as how long are they valid for?
A
- Details surface conditions as derived from METAR ad other surface observations.
- Issued every 3 hours
- Valid at observation
16
Q
How can you get weather before a flight?
A
- Call 1-800 wxbrief and get a weather briefing
- Look at METARs or TAFs
- Look at surface analysis charts, winds and temps aloft charts
- Use GFA tool on aviationweather.gov ( you can plot your flight and it will tell you the weather along the way)
17
Q
What should you look at in order to get current weather?
A
METARs
18
Q
How can you get weather while en route?
A
- Use Flight Service Stations
- You can also listen to AWOS as you go, but this is not the best option if you’re trying to plan for weather further than 30 miles out.
19
Q
What are AIRMETs and who are they intended for?
A
- Adverse weather conditions that MAY affect safety of flight (other than convective activity)
- Intended for all pilots as a safety precaution
20
Q
How often are AIRMETs issued, and how long are they valid for?
A
Issued as needed; valid for 6 hours
21
Q
What are the three types of AIRMETs and what is each specifically for?
A
- Sierra- mountain obscurations, IFR conditions
- Tango- moderate turbulence, surface winds of 30 knots or greater, and/or non-convective wind-shear
- Zulu- moderate icing, info about freezing levels
22
Q
How do you make a PIREP?
A
Give information to FSS or ATC if not too busy
23
Q
What is a SIGMET, how long are they valid for and when are they issued?
A
- adverse weather conditions that will likely affect safety of flight (for all aircraft)
- issued as needed
- valid for 4 hours (6 if hurricane)
24
Q
What are SIGMETs issued for?
A
- Severe or clear-air turbulence
- Severe icing not associated with thunderstorms
- Dust/sand storm that lowers visibility below 3 sm
- Volcanic ash
25
What are CONVECTIVE SIGMETs, how long are they valid for and when are they issued?
- Issued for any convective situation that the forecaster feels is hazardous to all aircraft
- Issued as needed
- Valid for 2 hours (updated hourly)
26
What is implied in a CONVECTIVE SIGMET?
implied severe turbulence, icing, and low level wind shear
27
In what conditions would a CONVECTIVE SIGMET be issued for (6)?
1. Hail 3/4 inches in diameter or greater
2. Embedded thunderstorms
3. Tornadoes
4. Surface winds greater than 50 knots
5. Thunderstorms covering at least 40% of a 3000 square mile area
6. Squall lines
28
What is windshear? What does it do to aircraft?
a sudden, drastic change in wind direction and/or wind speed over a very small area. It can rapidly change the performance of an aircraft.
29
What are mountain waves? What do these create?
mountains cause winds blowing across them to oscillate from their equilibrium; creates violent downdrafts and updrafts, turbulence, and strong shear and rotor zones.
30
What kinds of clouds are generally associated with mountain waves?
Lenticular clouds
31
What do isobars indicate? What does it mean if isobars are close together?
Indicate areas of similar pressure; isobars close together= turbulence (a high gradient of pressure can mean there are strong winds, while a low pressure gradient means weak winds)
32
Where does turbulence come from?
pressure, obstructions on the ground, uneven heating of the Earth's surface
33
What is density altitude made up of?
altitude, moisture, and temperature
34
What is density altitude?
Pressure altitude corrected for nonstandard temperature
35
At higher altitudes, is the air more or less dense? How does this affect our performance?
High altitude= less dense; causes poor performance
36
At lower altitudes, is the air more or less dense? How does this affect our performance?
Low altitude= more dense; causes better performance (gives more thrust in the engine because of the air molecules and more authority for the air foils)
37
Is hot air more or less dense than cold air? How does this affect our performance?
Hot air is less dense; which causes poor performance (better performance in cold air)
38
Is moist air more or less dense than dry air? How does this affect our performance?
Moist air is less dense than dry air; causes poor performance (better performance in dry air)
39
What is pressure altitude?
height above standard datum plane (29.92)
40
Would high density altitude cause poor or good performance on our aircraft? How come?
High density altitude= poor performance; causes less thrust and we would climb more slowly and possible not as high as usual.
41
How would a high density altitude affect takeoff performance?
It could cause a longer takeoff roll and slower climb, which could result in not being able to clear an obstacle.
42
What is standard temperature and pressure?
Standard temp= 15 degrees Celsius
Standard pressure = 29.92
43
What are the ingredients for structural icing?
1. Visible moisture
2. Temperatures near freezing
44
What are the types of structural icing? Explain them.
1. Rime ice= like the ice that gathers in our freezer (freezes instantly on impact with an aircraft)
2. Clear ice= most dangerous (has time to slide, freezes not instantly on impact with an aircraft)
3. Mixed ice= a mix of clear and rime ice
45
What are microbursts?
-strong downdrafts (up to 6000 fpm) from convective activity within a small area
- usually last 15 minutes
-spread outwards once they hit surface, which causes vertical and horizontal wind shears
-1-2 miles in diameter
46
Dewpoint
temperature where the air is going to be fully saturated and we will have visible moisture (fog, rain, ice, clouds , snow, etc.)
47
What is fog? What causes fog to form?
a cloud on the surface; when the temperature meets the dewpoint
48
What is radiation fog? When is this likely to occur?
- when there is cool air over a warm surface
- cool, clear nights
49
What is upslope fog? Where is this likely to occur?
- when warm air travels up a slope and cools
- mountains
50
What is advection fog? Where is this most likely to occur?
- Warm, moist air travels over cool surface
- Coastal areas (air over water warm, then it meets the coast where it is cooler)
51
What are the 4 associated things with unstable conditions?
1. good visibility
2. cumulus clouds
3. turbulent
4. if there's precipitation, there will be showers
52
What are the 4 associated things with stable conditions?
1. poor visibility
2. stratus clouds
3. smooth air
4. steady precipitation, if any
53
What are the ingredients of a thunderstorm?
1. Sufficient Moisture
2. Unstable lapse rate
3. Uplifting action
53
SLP: add 10 to the beginning of it on a...
METAR
53
If you find yourself in icing conditions, what should you do?
1. Get out of icing conditions
2. Turn on all the heats (carb heat, pitot heat, and cabin heat)
3. Find a place to land
53
AO2 on a METAR? AO1?
AO2: Precipitation Indicator (tells you the type of precipitation like if it's snow, rain, etc.)
AO1: does NOT have a precipitation indicator
54
What are three examples of uplifting actions?
1. Cold front shoveling air up
2. Wind hitting a mountain and blowing up
3. Heat making it rise
55
What type of weather is associated with cold fronts? What does a cold front do?
Unstable conditions; a cold front shovels air up, encouraging vertical movement and can cause thunderstorms
56
What type of weather is associated with warm fronts? What does a warm front do?
Stable conditions (low overcast layer, poor visibility, very smooth air although not good for VFR probably); a warm front comes and flows over the air mass, stopping the vertical movement, which causes a temperature inversion
57
What type of weather is associated with HIGH pressure systems?
Good weather, clear skies
58
What type of weather is associated with LOW pressure systems?
Bad weather, potential thunderstorms
59
What is a stationary front?
Mix of the weathers from warm and cold fronts
60
What is an occluded front? What type of weather is associated with occluded fronts?
When a cold front overtakes a warm front; thunderstorms, potential tornadoes and embedded thunderstorms
61
What is a squall line?
a line of thunderstorms unable to maneuver around; generally intense and formed rapidly; squall line thunderstorms move ahead of the cold front
62
What is wind shear? What's the most dangerous type?
a rapid change in wind speed/direction over a very small area and it can rapidly change the performance of an aircraft; low level wind shear
63
What is induction icing? What would you do to get rid of this ice?
icing that occurs on the induction system of an aircraft; turn on carb heat and pitot heat
64
What is instrument icing and what would it affect?
Ice in our pitot-mast (ice on the pitot tube and static port); would affect airspeed, altimeter, and VSI
65
What causes carb icing? How can ice form in high temperatures?
- Low pressure in the venturi, which makes the temperature lower.
- If the humidity is high enough, ice can form in high temperatures
66
What is fog?
A cloud that's on the surface
67
What is wind caused by?
Caused by atmospheric pressure differences.
68
What does air temperature vary by?
Varies by altitude, time, location, and season.
69
What three things does moisture exist as in the atmosphere?
Vapor, clouds, and precipitation
70
What three things must you have for precipitation to form?
Water vapor, sufficient lift, and a growth process that allows cloud droplets to grow large and heavy enough to fall.
71
What is an air mass?
A large body of air with generally uniform temperature and humidity.
72
Are cold masses fast or slow moving? Are they associated with stability or instability? Are they associated with good or poor visibility?
Fast moving; instability; good visibility
73
How does a high pressure system move?
Downward, outward, and clockwise
74
How does a low pressure system move?
Upward, inward, counter-clockwise
75
Are warm air masses fast or slow moving? Are they associated with stability or instability? Are they associated with good or poor visibility?
Slow moving; stability; poor visibility
76
What is turbulence caused by?
caused by the flow of wind being broken from its equilibrium by ground topography, convective currents, or wind shear.
77
What are convective currents?
Uneven heating of the earth's surface creates areas of rising warm air and sinking cool air. (For every rising current, there is a downward current)
78
What type of clouds would indicate convective turbulence? What other two things are associated with convective turbulence?
Cumuliform clouds; warm temperatures and barren surfaces
79
What is mechanical turbulence?
turbulence caused by obstructions. (mountain waves are caused by this)
80
What is a temperature inversion? What happens at temperature inversions?
When temperature increases with the increase of altitude. Strong wind-shear can occur, creating turbulence.
81
What is clear air turbulence? When is this type of turbulence most pronounced?
Higher altitude turbulence associated with wind-shear, caused mostly by jet streams. Most pronounced in the winter, where jet streams are strongest.
82
What are the stages of a thunderstorm?
1. Cumulus: strong convective updrafts beginning vertical development
2. Mature stage: most dangerous stage, strong updrafts and downdrafts; when precipitation starts.
3. Dissipating stage: strong downdrafts which cut off the storm's source of moisture; the end of a thunderstorm
83
What are some weather hazards (threats) to aviation activity?
1. Lightning
2. Adverse winds (wind-shear, gusts)
3. Downbursts (intense downdrafts similar to microbursts)
4. Hail
5. Icing
6. Tornadoes
7. Heavy precipitation
84
What kind of thunderstorms are tornadoes associated with?
Supercell thunderstorms
85
What should you do if you are about to fly into a thunderstorm?
1. Don't fly under it
2. Don't fly within 20 nm of the thunderstorm
3. Don't assume ATC will offer navigation around it
4. Advise ATC if deviation is necessary, and try to land to wait it out.
86
What should you do if penetration of a thunderstorm is unavoidable (you have to fly through it)?
1. Turn on anti-heating equipment (pitot heat, carb heat)
2. Plan a course that will take you through the storm in a minimum time
3. Fly at Va
4. Maintain straight and level
5. Turn all lights in cabin in order to not be affected by bright flashes of lightning
6. Tighten your seatbelt
7. Trust your instruments
87
What are three possible indications of microbursts?
1. Intense rain shafts at the surface
2. Virga at a cloud base
3. Dust halos
88
What should you do if you enter a microburst?
Increase power to full and try to climb out and through it.
89
What is steam fog?
When cold air moves over warm water
90
What is ice fog?
When water sublimates to ice in the air; forms only in extremely cold temperatures
91
What is frost? Where can this occur and what does it cause?
- Thin ice crystals on solid objects below the freezing point.
- Can occur on aircraft skin, disrupting the smooth airflow over the wings and can reduce lift
92
What are some circumstances that would make a diversion absolutely necessary?
1. Ceilings below VFR minimums at the airport of intended landing.
2. Thunderstorms
3. Winds exceeding personal minimums
4. Any weather condition the pilot determines will negatively affect the outcome of a landing at that airport
93
What would you use to get weather in flight?
1. Use the Flight Service Station (can call them on 122.2)
2. Listen to AWOS as you go
3. If you're on with flight following, they would tell you if there are any SIGMETS or convective SIGMETS on my route.
94
What would you do if you came across unforecasted weather?
Potentially divert the flight and land at a nearby airport, then assess the situation on the ground
95
What are the limitations to broadcasted weather and automated weather reporting stations?
- Broadcasted weather: since these aren't updated by the minute, the longer they have been around, the more likely they are to be incorrect (same with weather reports and forecasts)
- Automated Weather Reporting Stations: can be under maintenance and/or reporting old/incorrect information
96
What are the basic VFR weather minimums?
1. At least 5 sm of visibility
2. Ceiling no lower than 3,000 feet
97
Does wind naturally flow from high pressure to low pressure, or low pressure to high pressure? What is this called?
High pressure to low pressure; this is called Pressure Gradient Force
98
If a thunderstorm has an anvil, what does that tell us?
the direction the storm is moving
99
If you wanted to get weather the day before a flight, what type of weather briefing would you get?
an outlook briefing
100
What are the requirements for an aircraft to be a complex aircraft?
1. Flaps
2. Retractable landing gear
3. Constant speed propeller
101
How long are AIRMETs valid for? SIGMETs? CONVECTIVE SIGMETs?
- AIRMETs= 6 hours
- SIGMETs= 4 hours (6 hours for hurricanes)
- CONVECTIVE SIGMETs= 2 hours
102
What conditions are CONVECTIVE SIGMETs issued for?
E: embedded thunderstorms
A: a line of thunderstorms greater than 60 nm affecting 40% length
T: thunderstorm producing heavy precipitation affecting an area greater than 3000 square miles
S: severe/extreme turbulence associated with thunderstorms
H: hail at surface greater than 3/4 inches in diameter
I: icing that's severe and associated with thunderstorms
T: tornadoes
103
What causes a tropical storm?
1. Warm, moist air
2. Uplifting action
3. Unstable lapse rate
4. Winds moving in different directions near the ocean
104
What's the big difference between a tropical storm and a thunderstorm?
Tropical storm has higher temperatures than thunderstorms and converging winds
105
What would be three reasons to do a go around with a stabilized approach?
1. If there is a weird gust of wind that blows you off course
2. If an animal runs across runway
3. Someone hasn't cleared the runway
106
When is wake turbulence most dangerous?
When the aircraft creating it is heavy, clean (flaps and landing gear up), and slow
107
When does precipitation fog occur?
When it's hot outside, and then it rains.
108
What type of clouds suggest a smooth day?
Stratiform clouds
109
How would you know if you had induction icing?
A drop in RPMs
110
What would turning on carb heat do if you have induction icing?
RPMs would drop more because carb heat makes air hotter which makes it less dense; but then, it would get all the ice out and make engine run more smoothly (you should get an increase in RPMs when it is all out)
111
How is the weather around an anvil?
turbulent underneath and on top of an anvil
112
What type of wind do we prefer for takeoff and landing? Why?
Headwind; it will help build our airspeed and get over obstacles
113
If the temperature is decreasing more rapidly then two degrees per thousand feet=
creates an unstable atmosphere
114
Would a temperature inversion create a stable or unstable atmosphere?
Stable
115
Why should you stay 20 nm away from a thunderstorm?
1. Hail can be thrown up to 20 nm out of the way of a thunderstorm
2. Microbursts
3. Turbulence
116
What does a dollar sign mean on a METAR?
the weather observing equipment needs maintenance
