single-cell and multicell thunderstorms Flashcards
cumulus congestus
- dominated by updrafts
reaches a height of 1.5 times the cloud base, but then is dissipates due to
cumulus stage
-after cumulus congestus dissipates, the air is moist and if updraft persists, new cumulus clouds form
- cumulus will grow if wind-shear is weak
Mature stage
Updraft persists but downdraft forms as a result of drag due to rain, ice etc.
- main feature of this stage: existence of updraft and downdraft and precipitation
- weak wind shear causes anvil to form at tropopause
Dissipation stage
- loss of positive buoyancy and moist updraft
1. storm moves over region where convection is not pronounced
2. downdraft cuts off updraft
3. interaction bw updraft and downdraft diminishes updraft
Cell motion vs storm propagation
- cell motion: cells are carried along by the mean winds in the layer containing the storm
cell propagation: due to new updrafts being triggered by a gust front moving with a velocity different from the velocity of the storm
- winds flowing through the cell as opposed to the cell moving with the winds
- new cells form where the warm and moist air is rising