Thunderstorms Flashcards
What is the term ‘Thunderstorm’ given to?
Cumulonimbus clouds which produce thunder and lightning.
What are the three stages of a Thunderstorm?
Cumulus Stage
Mature Stage
Dissipating Stage
Describe the cumulus stage of a Thunderstorm and state the duration
The growing stage. Free or forced convection triggers a very quick growth from Cu to TCU.
Duration : 30 minutes
Describe the mature stage of a Thunderstorm and state the duration
If the cloud is below freezing, raindrops and hailstones grow in size until their weight can no longer be supported.
The drops fall as heavy precipitation, dragging cold air with them.
Upon reaching the ground, the air spreads out in all directions creating a microburst.
Duration : 30 minutes
Describe the dissipating stage of a Thunderstorm and state the duration
The decaying stage. The typical anvil shape is formed and the precipitation gradually decreases.
Duration : 2 hours or more, depending on if regeneration occurs.
What hazards are associated with Thunderstorms?
Turbulence
Hail
Icing
Lightning
Static
Windshear
How are thunderstorms classified?
By the source of trigger action.
Air Mass
Frontal
Orographic
Convective (Insolation)
What is an Air Mass Thunderstorm?
When a colder air mass passes over a warm surface. The lower layers of the air mass are heated, causing convection, leading to a thunderstorm.
What is a Frontal Thunderstorm?
As a cold front advances, it pushes underneath the warm moist air, causing it to rise, leading to a thunderstorm.
What is an Orographic Thunderstorm?
Upon reaching a hill, air is forced upwards. Common where moist tropical air masses are blown from a sea to a mountainous coast, leading to thunderstorms.
What is an Insolation Thunderstorm?
Strong heating of a land mass by the sun causes air to rise, leading to a thunderstorm.
