Ordinary-cell convective storms - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 116

Figure 3.19b. Byers-Braham conceptual model of an ordinary-cell convective storm. (Top)
Cumulus stage, characterized by a buoyant updraft; (bottom) dissipating stage, characterized
by precipitation, downdraft, and gust fronts (from Rotunno et al., 1988)

Project in the 1940s. A cell's lifetime is therefore at least 2(12 km/10m s 1 ) ¼
2,400 s (i.e., 40min) for a 12 km deep troposphere; additional time may be
needed to account for the complete blocking off by the downdraft of potentially
unstable air into the updraft and for storm initiation. Cells that last for much
longer periods of time than the time it takes air parcels to travel to the tropopause
and then downward to the ground will be discussed a bit later. Storms that behave
like ordinary cells and consist of only one cell are sometimes referred to as
''pulse''-type, single-cell convective storms. They occur in environments of

moderate CAPE and weak vertical wind shear.