Thunderstorms Flashcards
What 3 conditions are required for a thunderstorm formation
- Unstable atmosphere
- Supply of moist air
- Lifting triggering action
What temperatures are required for a thunderstorm development
Level 8000
Air Parcel Temperature | Environmental Temperature | Temperature Difference
Air Parcel Temperature | Environmental Temperature | Temperature Difference
+10℃ | +4℃ | 6℃
What temperatures are required for a thunderstorm development
Level 6000
Air Parcel Temperature | Environmental Temperature | Temperature Difference
Air Parcel Temperature | Environmental Temperature | Temperature Difference
+13℃ | +8℃ | 5℃
What temperatures are required for a thunderstorm development
Level 4000
Air Parcel Temperature | Environmental Temperature | Temperature Difference
Air Parcel Temperature | Environmental Temperature | Temperature Difference
+16℃ | +12℃ | 4℃
What temperatures are required for a thunderstorm development
Level 2000
Air Parcel Temperature | Environmental Temperature | Temperature Difference
Air Parcel Temperature | Environmental Temperature | Temperature Difference
+19℃ (Dew point) | +16℃ | 3℃
What temperatures are required for a thunderstorm development
Surface
Air Parcel Temperature | Environmental Temperature | Temperature Difference
Air Parcel Temperature | Environmental Temperature | Temperature Difference
+25℃ | +20℃ | 5℃
In what air type (WARM or COLD) do thunderstorms tend to develop in
Why
WARM AIR
Warm air can contain more moisture than colder air
Frontal lifting thunderstorms can occur in which front
COLD & WARM
Why are warm or occluded front thunderstorms more dangerous
EMBEDDED CLOUDS
associated layer cloud invisible to pilot
TCU / CB / TS
What are 3 types of lifting that can cause thundestorms
- Frontal lifting
- Orographic lifting
- Convergence (2 different air masses meet)
Convergence often happens at coastal locations
What are the 3 stages of a thunderstorm
- Towering Cumulus
- Mature
- Dissipating
During cumulus stage of a thunderstorm, what is the typical vertical air current rate
> 4000 fpm
feet per minute
Typically, how long does the mature stage of a thunderstorm last
1 hour
In a mature stage of a thunderstorm, where can vertical air currents be found
INSIDE & IN VICINITY
What are the wind directions for each stage of a thunderstorm;
1. Cumulus Stage
2. Mature Stage
3. Dissipating stage
- Updraft only
- Updraft and down draghts
- Down draughts only
What speeds (kts) can downdraghts be in mature stage
How far away can they be felt (nm)
- 40kts
- 20nm
At what stage of a thunderstorm may roll clouds appear
MATURE STAGE
What causes the flat top to form during the dissipating stage of a thunderstorm
INVERSION
Why does an anvil form
Wind blowing cloud aloft
Thunderstorm Hazard
Where can turbulence occur
In reference to the cell
INSIDE & OUTSIDE CELL
What is a major risk to the airframe and why
EXTREME STRESSES
Draughts exceed rate of climb of aircraft
What range can up and down draughts vary by
fpm
+4000 fpm to -4000 fpm
Where is windshear from downdraughts most hazardous
- Immediately below the cloud
- At the gust front
What does a mammatus cloud look like
What does it indicate
- Irregular egg box
- Indicates turbulence
What 4 pieces of equipment are most at risk from a lightening strike
- Compass
- Comms
- Nav
- Onboard computer
Which aircraft navigational feature will be unreliable near a thunderstorm
Automatic Direction Finder
(ADF)
What are 2 effects the pilot may suffer following a lightening strike
- Temporarily blinded
- Temporarily deafened
Thunderstorms do not travel with the ____ winds. They tend to travel in the direction of wind at ____ hPa (????? ft)
- Prevailing lower winds
- 500 hPa
- 18,000 ft
What is the minimum margin to avoid a thunderstorm
10nm
What is the cloud name that looks like an irregular egg box and indicates turbulence
MAMMATUS CLOUD
