Variability of Surface Outflows, Cold Pools,
in a Large Parameter Space Study of Convective Storms
D. J. Perkey, Cody Kirkpatrick*, and E. W. McCaul, Jr.
Poster presentation at the 2008 AGU Fall Meeting, abstract A13A-0226. *Presented by C. Kirkpatrick.
Using results from a large set of three-dimensional cloud
resolving model simulations, we investigate the sensitivity of storm outflows,
downdrafts, and cold pools to background environmental conditions. The dominant
right-moving storm in each of over 200 unique experiments is analyzed, and its
properties averaged during the second hour of 2 h simulations, to assess the
general relationships between storm outflow characteristics and environmental
The strongest surface wind gusts and largest areas of outflow are produced when convective available potential energy (CAPE) and bulk tropospheric wind shear are large, these being environmental conditions that are hallmarks of vigorous, organized convection. Strong winds are also more widespread when the atmospheric precipitable water (PW) is large, which permits greater production of precipitation aloft, and when the lifted condensation level (LCL) is raised, allowing increased evaporation of falling hydrometeors in the downdraft. Storm cold pool temperature deficits and areal coverages exhibit more complicated relationships, but cold pools are generally larger and relatively colder in warm environments (i.e., high PW) and when CAPE is large. These findings help clarify the environmental conditions that influence the surface ``sensible weather'' produced by deep, moist convection.
This is a low-resolution reproduction of all the panels on the poster. If you would like to examine any of the figures in more detail, please email me at the link on the previous page for a copy.