Geoscience Reference
In-Depth Information
Tropopause, 12,000 m
(40,000 ft)
Upper-level
wind direction
Combining
cumulus clouds
Strong
convectional
updraft
Uplift of
warm air
Falling precipitation
causes downdraft
Condensation level
Gust front
(a) Cumulus and developing stages
(b) Mature stage
Upper-level
wind direction
Anvil
Heavy
rain
Gust front
(c) Dissipating stage
(d) Anvil head
Dissipating storms
Mature storms
Advancing cold front
pushing warm, moist
air into storms
Gust front
Developing storms
(e) Squall line
Figure 8.12 Stages of thunderstorm development.
(a) Convection or advancement of a cold front forces air to rise
during the cumulus stage. As the storm evolves, convection strengthens and the system moves into the developing
stage. (b) The storm is most intense during the mature stage when strong updrafts occur next to strong downdrafts of
cold air. (c) Formation of an anvil head. This feature develops in strong storms at the altitude where convection can no
longer continue, causing the upper clouds to be sheared downwind. (d) Anvil head of a thunderstorm. Note how the
cloud appears to be spreading outward at the top. (e) Squall lines consist of several individual thunderstorms that form
along an advancing cold front.
