Met Flashcards
How does variation in air density affect aircraft performance?
Max take off weight, lifting force of the wings, thrust of propeller jet
What is the main disadvantage of visual satellite imagery?
Cannot be used between sunset and sunrise
This limits the effectiveness of visual satellite imagery during nighttime.
Cloud formed by air lifted over mountains is caused by?
Orographic uplift
Orographic uplift occurs when air is forced to rise over a mountain range.
What type of fog is mostly to occur at sea?
Advection fog
Advection fog forms when warm, moist air moves over cooler water.
What is the most likely horizontal visibility during flight in cloud (excluding cirrus)?
Less than 1000m
Visibility in clouds is typically reduced due to water droplets obstructing sight.
What are the most ideal conditions for the formation of radiation fog?
- High relative humidity at low level and cloudless sky
- Plentiful supply of condensation nuclei and overcast lower level cloud
- Surface wind below 5kts
- Strong afternoon sunshine and cloudless sky
These conditions promote cooling and moisture accumulation near the ground.
What is the most likely mechanism for clearing a radiation fog?
Solar radiation warming the ground
This process reduces humidity and promotes evaporation, dissipating the fog.
What is heavy continuous rain most likely an indicator of?
Nimbostratus/thick Altostratus
These cloud types are associated with prolonged, steady precipitation.
Which cloud type is most associated with hail?
Cumulonimbus
Cumulonimbus clouds are known for their vertical development and severe weather, including hail.
Which of the following are likely effects of volcanic ash cloud on aircraft?
- Engine failure and windshield abrasion
- Extreme passenger discomfort
- Loss of cabin pressure
Volcanic ash can severely impact aircraft systems and safety.
In the International Standard Atmosphere (ISA), at what height above MSL is the freezing level?
10000ft
This is a standard reference for aviation meteorology.
What happens to air temperature in an inversion layer?
Temperature remains the same or increases with increasing height
Inversions trap cooler air near the surface, leading to temperature increases aloft.
Which is the most likely cloud formation process in an unstable atmosphere?
Convection
Convection leads to rising air and cloud formation in unstable conditions.
What cloud type is most commonly associated with morning drizzle?
Stratocumulus
Stratocumulus clouds can produce light, steady precipitation.
What is the Inter Tropical Convergence Zone (ITCZ)?
The area where the Trade Winds meet
This zone is characterized by low pressure and frequent thunderstorms.
Where do tropical cyclones form?
Either over land or over sea
Tropical cyclones typically form over warm ocean waters but can affect land areas.
Pre-requisite/s for the development of a tropical cyclone?
- Sea surface temperature greater than 26°C
- Pre-existing surface depression
- At least 5°C latitude from the equator
These conditions are essential for cyclone formation.
The reported wind in a METAR/SPECI is measured at which level?
10m AGL
This height is standard for wind measurements in aviation.
What is the cloud height reference level used in a TAF?
Above mean sea level
This standard helps pilots understand cloud heights relative to the terrain.
The term BKN (broken) in a forecast signifies what?
5 to 7 Oktas
This indicates the extent of cloud cover.
The term TEMPO in a forecast signifies what?
Temporary weather lasting less than 30 minutes
This helps pilots prepare for short-lived weather changes.
When is Clear Air Turbulence (CAT) most likely?
Near an upper level jet stream
CAT is often encountered at high altitudes near jet streams.
What is a cause of radar interpretation errors?
Signal blocking due to obstructions
Can insect swarms and bushfire smoke be detected by radar?
Yes
Radar can detect various particulates in the air.
Radar struggles to accurately detect what?
Drizzle
Drizzle droplets are often too small for radar to pick up effectively.
Sea breezes are most likely to commence during which of the following time periods?
Between 9AM and midday
This is when land heats up, causing air to rise and drawing in cooler sea air.
During what time period is radiation fog most likely to form?
Between midnight and 6AM
This is when temperatures drop, leading to condensation.
In a fog, what might the typical visibility be?
Between 1km and 2km
Fog typically reduces visibility significantly.
What clouds produce microbursts?
Cumulonimbus (CB)
Microbursts are severe downdrafts associated with these clouds.
What are the primary pre-requisites for the formation of a thunderstorm?
- Trigger
- Instability
- Moisture
These factors are essential for thunderstorm development.
What is the best estimate of QNH from a barometer reading of 1010hPa at 180ft above ground?
1004
QNH adjusts the pressure reading to mean sea level.
When flying towards a low pressure system without changing the departure QNH, what will your actual height be?
Lower than your indicated height (on the altimeter)
This is due to the lower pressure in the low system.
A cloud with an air temperature of -13°C will most likely consist of what?
Ice crystals
At this temperature, clouds typically contain ice.
Large supercooled droplets existing at -8°C within a well-developed convective cloud are primarily dangerous to aircraft because of what?
Clear ice formation on the airframe
Supercooled droplets can freeze on contact, creating hazardous conditions.
A SIGMET warning can be issued for?
- Tropical cyclones
- Volcanic Ash
- Embedded thunderstorms
SIGMETs are crucial for informing pilots of hazardous weather conditions.
