Cumulus Clouds and Thunderstorms
Cumulus Clouds
- puffy, “popcorn-like” clouds
- cumulus humilis (humble):
- cumulus congestus (heap):
- towering cumulus clouds
- heating causes vertical updrafts
- air parcels cool as they rise
- excess water vapor condenses
- latent heat released
- causes more updrafts
Thunderstorms
- cumulonimbus:
- thunderstorm cloud
- very large (tall), thick clouds
- thunderstorm = cumulonimbus clouds with lightning and thunder (and commonly rain)
- top of cloud is near top of troposphere
- base of cloud is near the ground
- strong updrafts and downdrafts (turbulent)
- looks like a mushroom or an anvil (well-developed)
- anvil can be 10s of mile in diameter
- if very strong updrafts, then the dome of the cloud overshoots above the anvil
- storm energy from temperature and humidity
Thunderstorm Occurrence
- more commonly occur in:
- tropical locations: abundant sunshine (heat) and moisture
- late afternoons in the summer: most surface heating
- also in regions with convergent winds and/or lifting
- mountains
- land/sea boundary
Thunderstorm Fuel
- need constant inflow of warm, moist air or they die out
- most thunderstorms use up fuel (warm, moist air) and choke on their exhaust (cool, dry air)
- last only a half hour to an hour