Weather Flashcards
Which side of a low pressure front would you want to fly on to take advantage of tailwinds?
It depends on which direction you’re flying. If you’re flying west, the north side would benefit you. If you’re flying east, the south side would benefit you. If you’re flying north, the east side would benefit you, and lastly, if you’re flying south, the west side would benefit you
What are the thin grey lines (isobars) Close vs far isobars?
Shows differences in pressure
What stage would you most likely encounter the anvil top?
Mature stage
How to differentiate hail from rain on radar?
Hail can be detected using radar. On Doppler radar, hail generally sends a return signal that looks like extremely heavy rainfall. Dual-polarization radar technology, used by the NWS, can help tell the difference between hail, ice pellets and rain, and even determine hail size.
If it is 5C at altitude could we get ice on wings?
Yes. It depends on the temperature of the surface of the aircraft. If descending from very cold altitudes you can definitely accumulate ice with an OAT of 5C.
How often do winds and temperature aloft forecasts come out?
At a global level, winds aloft forecasts are updated every 6 hours. For North America, Europe, and Australia, these forecasts are updated every hour. The time resolution for global forecasts is every 3 hours up to 30 hours (e.g., 00Z, 03Z, 06Z, 09Z).
Heavy rain / heavy snow equates to what visibility?
1/4 vis
Name the different types of fog and what causes them?
(1) Advection fog
(2) Radiation fog (ground or valley fog)
(3) Upslope fog (Cheyenne fog)
(4) Steam fog (arctic sea smoke)
(5) Frontal fog (forms from the evaporation of warm precipitation as it falls into drier, colder air in a frontal system)
(6) Ice fog (This type of fog is only seen in the polar and artic regions. Temperatures at 14 F (-10°C) is too cold for the air to contain super-cooled water droplets so it forms small tiny ice crystals.)
At a cold weather airport , is your true altitude higher or lower?
cold weather = lower true alt. warm weather = higher true alt
Is frost considered structural icing?
Yes
What is clear air turbulence?
Turbulence not associated with cloud formations
Where is the most severe turbulence in a thunderstorm?
top 1/3 of the thunderstorm where updrafts and downdrafts meet
What would you do if there was a microburst over the field and you were five minutes from landing?
Maybe ask for vectors to a hold and wait it out. Or divert to alternate.
Why does the thunderstorm flatten at the top?
Mature thunderstorm cells can rise so high that they reach the stratosphere, where winds will spread and flatten the top. This makes the anvil-shaped thunderstorm clouds that you may have seen.
As a pilot how can you visually tell which stage the thunderstorm is in?
updrafts in cumulus clouds, due to lifting force Mature stage when it starts to rain Dissipating stage when the cloud opens up and starts to dry out and the anvil shape forms
Mountain waves can extend how far from mountains?
700 miles.
What is the definition of severe icing?
Icing accumulation to the point that equipment fails to control removal
When can you fly through known icing?
If you have anti-icing capabilities that will not be exceeded by the icing condition
Can your temp ever go below the dewpoint?
Yes but it wont last. When temp reaches same dew point, air is 100% saturated
What happens when a cold front collides with a warm front?
What altitude does the tropopause start?
20,000’ near the poles, 65,000’ near the equator. Approximately 36,000’ over the US
If you are given a picture of a thunderstorm, which way is TS moving?
whichever way anvil is pointed
What is a lenticular cloud?
A lenticular cloud is a lens-shaped cloud that normally develops on the downwind side of a mountain or mountain range. This occurs when stable, moist air flows over a mountain, creating a series of oscillating waves. If the temperature at the crest of the wave equals the dew point temperature, condensation occurs in a lens formation. As the air falls down the trough of the wave, where the temperature and dew point temperature are not equal, evaporation occurs. Thus, a wave cloud, or a series of lenticular clouds, is capable of forming.
What does ACSL meant on a chart?
Alto Cumulus Standing Lenticular
What are super cooled water droplets?
Water droplets who’s temperature is cooled below that of freezing (32F), and they freeze immediately on contact with any surface they touch
What is mountain wave?
oscillations to the lee side of high ground resulting from the disturbance in the horizontal air flow caused by the high ground.
What are the different types of Fronts?
Cold Front
Occluded Front
Warm Front
Stationary Front
What are the different stages of a thunderstorm?
Cumulus (3-5 mile height) – The lifting action of the air begins, growth rate may exceed 3000 fpm
Mature (5-10 miles height) – Begins when precipitation starts falling from the cloud base. Updraft at this stage may exceed 6000 fpm. Downdrafts may exceed 2500 fpm. All thunderstorm hazards are at their greatest intensity at the mature stage.
Dissipating (5-7 miles height) – Characterized by strong downdrafts and the cell dying rapidly.
What is the most dangerous stage of a thunderstorm and why?
The mature stage is the most likely time for hail, heavy rain, frequent lightning, strong winds, and tornadoes
What are some weather information services?
Flight Service Station (FSS)
AWC
EFB software i.e., ForeFlight, Jeppeson Pro Flight
Flight Information Services-Broadcast (FIS-B)
Automatic Terminal Information Service (ATIS)
Automated Surface Observation System (ASOS) (hourly)
Automated Weather Observation System (AWOS) (minute by minute)
ATC - Center weather advisories
Onboard weather radar
XM Satellite weather service
What are the different types of weather briefings?
Standard – A full briefing. Includes: adverse conditions, VFR
not recommended, synopsis, current conditions, enroute
forecast, destination forecast, winds aloft, NOTAMs and ATC
delays.
Abbreviated – Updates previously received information from
mass disseminated sources or a previous briefing.
Outlook – For departures 6 or more hours away. Includes
forecasts for the time of the flight.
Inflight – FSS also provides any of the above types in flight
What is an Airmet and what are the different types?
An advisory of significant weather phenomena at lower intensities than those which require the issuance of SIGMETs. These conditions may affect all aircraft but are potentially hazardous
to aircraft with limited capability.
- Valid for 6 hours.
- AIRMET (T) - describes moderate turbulence,
sustained surface winds of 30 knots or greater,
and/or non-convective low-level wind shear. - AIRMET (Z) - describes moderate icing and
provides freezing level heights. - AIRMET (S) - describes IFR conditions and/or
extensive mountain obscurations.
What is a Sigmet?
A non-scheduled inflight advisory with a maximum forecast period of 4 hours. Advises of non-convective weather potentially hazardous to all types of aircraft. A SIGMET is issued when the
following is expected to occur:
- Severe icing not associated with thunderstorms
- Severe or extreme turbulence or Clear Air Turbulence (CAT) not associated with thunderstorms.
- Dust storms, sandstorms lowering surface
visibility below 3 miles.
What is a Convective Sigmet?
An inflight advisory of convective weather significant to the safety of all aircraft.
- Issued hourly at 55 minutes past the hour for the western (W), eastern (E) and central (C) USA.
- Not issued for Alaska or Hawaii.
- Valid for 2 hours.
- Contains either an observation and a forecast or only a forecast.
What does a Convective Sigmet entail?
Severe thunderstorms due to:
◦ Surface winds greater or equal to 50 knots
◦ Hail at the surface greater than 3/4 inch in diameter
□ Tornadoes
□ Embedded thunderstorms of any intensity level
□ A line of thunderstorms at least 60 miles long with thunderstorms affecting at least 40% of its length.
□ Thunderstorms producing heavy or greater precipitation affecting at least 40% of an area of at least 3000 square miles.
Any Convective Sigmet implies severe or greater
turbulence, severe icing, and low level wind shear.
What is a Surface Analysis Chart?
Generated from surface station reports. Shows pressure systems, isobars, fronts, air mass boundaries (e.g,: dry lines and outflow boundaries) and station information (e.g,: wind, temperature/dew point, sky coverage, and precipitation). Issued every 3 hours.
What is deicing fluid?
De-icing solution is a mixture of propylene glycol and water, heated to around 150 degrees, and sprayed under pressure to the wings of an aircraft.
What is a Microburst?
A microburst is a localized column of sinking air (downdraft) within a thunderstorm and is usually less than or equal to 2.5 miles in diameter. When the updrafts become too weak to hold all the rain it sinks and creates a massive amount of rain fall.
What are the two types of Microbursts?
1) Wet microbursts
2) Dry microbursts.
What are the different cloud types?
High Clouds (16,500-45,000 feet)
Mid-level Clouds (6,500-23,000 feet)
Low Clouds (less than 6,500 feet)
What are all the possible low clouds?
Cumulus
Stratus
Cumulonimbus
Stratocumulus
What are all the possible mid level clouds?
Altocumulus
Altostratus
Nimbostratus
What are all the possible high level clouds?
Cirrus
Cirrostratus
Cirrocumulus
