Thunderstorm Flashcards
All thunderstorms require:
Unstable air
Lifting action
High moisture content
3 stages of thunderstorms
Cumulus stage
Mature stage
Dissipating stage
Cumulus stage
Formation of a cumulus cloud that builds up into a towering cumulus
Mostly updrafts
No precipitation
Mature stage
Highest incidence of precipitation
Lighting, microbursts, gust fronts, hail, tornadoes can occur
Updraft 6000FPM (ft per min) downdrafts 2000FPM
Dissipating stage
Precipitation cools down, breaks the updrafts
Top of cloud spreads out into an anvil form
2 types of thunderstorms
Air mass thunderstorms
Frontal thunderstorms
3 types of air mass thunderstorms
Convection thunderstorms
Advection thunderstorms
Orographic thunderstorms
Convection thunderstorms
Caused by uneven heating of the ground
Occur in the afternoon/ early evening
Dissipate late evening/ overnight
Clouds scattered over large area
Advection thunderstorms
Caused by cold air passing over warm surface
Over land: Occur in the afternoon, Dissipate in late evening/ overnight, Clouds scatter over large area, Has northerly flow
Over water: Occur in morning, dissipate with southerly flow, clouds close together
Orographic thunderstorms
Caused by air being lifted by sloping ground (ie. mountain)
Occur day/ night
Dissipate with a change in wind direction
Clouds form in stationary line
Single-cell thunderstorms
Individual air mass thunderstorms
Supercells/ supercell thunderstorms
Large clusters of air mass trhunderstorms
2 types of frontal thunderstorms
Cold front thunderstorms
Warm front thunderstorms
Cold front thunderstorms
Clouds in a line parallel to the front
Occur day/ night
Dissipate with the movement of the front
Warm front thunderstorms
Embedded in stratiform clouds, not as visible as cold front thunderstorms
Occur day/ night
Dissipate with movement of the front
10 area of concern when flying near a thunderstorm
Turbulence
Hail
Lightning
Icing
Squall lines
Tornadoes
Low ceiling & visibility
Heavy rain
Microbursts
Gust fronts
Severe turbulence is present in all ___ clouds
cumulonimbus
Roll cloud
Low-level, horizontal, tube-shaped accessory cloud completely detached from the base of a cumulonimbus cloud
4 types of lightning
In-cloud (sheet lightning)
Cloud to cloud
Cloud to ground
Distant
Squall lines
Non-frontal, narrow bands of highly active thunderstorms
Microbursts
Sudden powerful downdrafts within a thunderstorm
Gust fronts
Result of strong downdrafts in the mature stage of a thunderstorm reaching the ground and spreading out horizontally
Usually has significant turbulence
Effects of cumulus cloud on flight
Result in a bumpy flight beneath and in the cloud
Effects of towering cumulus cloud on flight
Result in turbulence
Icing is possible at altitudes above freezing level
Strong updrafts below and in the cloud
Effects of cumulonimbus cloud on flight
Result in severe turbulence
Severe icing
Accompanied by thunderstorm, precipitation, wind, hail, lightning
Effects of altocumulus castellans cloud on flight
Result in turbulence and icing
Precipitation may be present
Hazards association with CBs:
Rapid changed in barometric pressure
Abrupt changes in wind speed & direction
Moderate to severe icing
Hazardous disturbances
Turbulence
Extreme weather
