1. 4 3 . 1
Thunderstorms

2. Thunderstorms
A weather phenomena whose presence creates extremely serious hazards to flying. They may be accompanied by:
Thunder
Lightning
Strong Vertical Drafts
Severe Gusts and Turbulence
Heavy Rain
Hail
Micro/Macrobursts
Tornadoes
Severe Wind Shear
It is a weather condition of which a pilot should be enormously respectful.
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3. Thunderstorms must have the following requirements:
Unstable air to high levels
Lifting agent
High moisture content
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4. Life of Thunderstorm Stage 1 Initial or Cumulus Stage
Strong updrafts prevail (unstable air to high levels).
Temperature is higher inside the cloud than the surrounding air.
Diameter ranges from 1 to 2 miles (but may become as large as 6 miles).
Steep lapse rate.
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5. Life of Thunderstorm Stage 2 Mature Stage
Updrafts penetrate to great heights.
Downdrafts start in middle and lower level cell.
Precipitation starts.
Stage usually lasts 15 to 30 minutes (may last as long as 60 minutes).
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6. Life of Thunderstorm Stage 3 Dissipating Stage
Downdrafts occupy all but top of cloud where updrafts persists.
Rain starts to slow and stop.
Top of cloud frays into anvil shape.
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7. Types Air Mass Frontal Usually form on hot summer days
Relatively easy to avoid
Form as a result of either convection or orgraphic lift.
Frontal
Associated with cold fronts
Usually form in a line that may extent for hundreds of miles of cold front, known as LINE SQUALL
Can develop at warm front and may be embedded.
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8. Corfirmation
Stage
NOTE: You must use the buttons in the Confirmation Stage

9. Meteorology Thunderstorms
Let's try a few review questions on Meteorology:
Question #1 - Name a requirement for thunderstorm development. A
Lifting Agent B
Moisture C
Unstable
All of the above D
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14. Meteorology Thunderstorms
Let's try a few review questions on Meteorology:
Question #2 - In what stage are updrafts the strongest? A
Initial B
Mature C
Dissipating
Both B and C D
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19. Thunderstorm Hazards Turbulence Winds
could overstress aircraft or cause loss of control
downdrafts as strong as 2000 feet per minute and updrafts as strong as 6000 feet per minute that can severely cripple aircraft
strongest between 12, ,000 feet in mature stage
can be experienced, in clear air up, to 20 miles away from severe cells
can be severe in micro/macrobursts and at gust front
Winds
danger of gusts up to 80 knots with rapid changes in direction
gust front generates strong, gusty winds near the surface which can change direction by 180° and gust up to 50 knots in seconds
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20. Thunderstorm Hazards Hail Icing could cause serious structural damage
can be encountered outside of cloud as it is thrown upward and outward by active cells
Icing
abundance of supercooled water droplets, will cause severe icing
most severe during the mature stage
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21. Thunderstorm Hazards Lightning Pressure
hamper vision for seconds at a time
greatest likelihood of strike at temperatures between -5°C and +5 °C
solid state circuitry is particularly vulnerable to strikes
electrical may be disrupted
possibility of igniting fuel vapour in fuel cells
Pressure
rapid changes in pressure cause unreliable altimeter readings
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22. Thunderstorm Avoidance
If you must fly past one, stay at least 15 miles away and pass to the right.
A thunderstorm is an area of low pressure (anti-clockwise and inward). You will encounter more favorable winds (tailwind) if you pass to the right.
Never fly under a thunderstorm due to up/down drafts.
BEST ADVISE - STAY ON THE GROUND
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23. Confirmation Stage
NOTE: You must use the buttons in the Confirmation Stage
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24. Can severely cripple an aircraft
Meteorology
Thunderstorms
Let's try a few review questions on Meteorology:
Question #3 - Match
Can severely cripple an aircraft
Can cause serious structural damage A
Turbulence B
Hail A
Turbulence B
Hail
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29. Meteorology Thunderstorms Congratulations!!
You have now completed the Thunderstorm lesson of the Meteorology Module. Of course, this lesson is always available to you for future reference if required.
You are now ready to move along to the next Meteorology lesson you have not completed or to any other module you wish. You can advance to the Self Test Module if you feel ready to challenge the final exam.
Good Luck!
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