Water-Ice and Water-Updraft Relationships near −10°C within Populations of Florida Cumuli

Abstract

From an in-cloud microphysical data set collected in Florida convective towers that were penetrated close to their tops near -10°C, evidence is presented to show a sequential development of cloud water, rainwater, graupel and crystalline ice as the cloud ages. Of particular interest is the very rapid onset of graupel that appears on repeat penetrations of some, but not all, towers. A separate data set shows a large scatter in the relationship between maximum value of cloud water and vertical velocity which points to the conclusion that measurements of cloud water, by itself, can be misleading as an indication of growth activity. The sequential pass data showing the evolution of ice and water are consistent with a rime-splintering, secondary ice production hypothesis.