ENVIRSC 1A03 Lecture Notes - Lecture 18: Outflow Boundary, Cumulus Cloud, Sea Breeze

• School: McMaster University
• Department: Environmental Science
• Course: ENVIRSC 1A03
• Professor: Luc Bernier

Document Summary

Thunderstorms are storms with vertical motion sufficient to cause lightning and thunder: are characterised by cumulonimbus clouds, and vary in intensity. Air mass thunderstorms are isolated and short lived. Severe thunderstorms may produce strong winds and rain and last short amount of time. Multi cell thunderstorms are massive, well-organized complexes of storms. Air mass thunderstorm consists of several updrafts each following a sequence of stages: the cumulous stage in which uplift begins and clouds form. An isolated updraft of warm moist air leads to the formation of an isolated cumulus cloud. It mixes with dry surrounding air as a result of entrainment. Condensation leads to continued updraft within the cloud: the mature stage. Strong updraft and downdraft occur within the cloud as part of organized convection. This stage is characterized by heavy rain fall, gasty winds and lighting. The end of the cloud is due to temp inversion at tropopause: dissipating stage. Precipitation diminishes and the sky begins to clear.