Search Results

You are looking at 1 - 10 of 11,499 items for :

  • Refine by Access: All Content x
Clear All
John Molinari
,
David M. Romps
,
David Vollaro
, and
Leon Nguyen

to 300 km the maximum shifted to downshear right. Abarca et al. (2011) updated these results using a long-range network that sampled storms over open ocean as well as near land. The vast majority of electrified convection outside the 100-km radius occurred downshear or downshear right. Molinari and Vollaro (2010) showed that convective available potential energy (CAPE) averaged from 75- to 400-km radii was 60% larger downshear than upshear. They hypothesized that the larger CAPE arose from

Full access
David M. Romps

1. Introduction Convective available potential energy (CAPE), which is a function of the atmosphere’s temperature profile and near-surface humidity, is the maximum specific vertical kinetic energy w 2 /2 that storm clouds can theoretically attain while rising. CAPE plays a critical role in the prediction of severe weather ( Johns and Doswell III 1992 ; Brooks et al. 1994 ; Rasmussen and Blanchard 1998 ; Rasmussen 2003 ; Brooks et al. 2003 ) and lightning ( Williams et al. 1992 , 2002

Full access
Reinhold Steinacker

. Since then, it was realized that cyclogenesis in the extratropics needs a certain amount of initial baroclinicity. The application of parcel theory for convective processes in the atmosphere led to the formulation of the convective available potential energy (CAPE; Moncrieff and Miller 1976 ). It is interesting to note that Margules (1905) also treated a case with a vertical rearrangement of air volumes but came to the conclusion that (dry) unstable stratification is rarely observed in the

Full access
David K. Adams
and
Enio P. Souza

1. Introduction Understanding the relationship between the energy available for atmospheric convection and convective activity has engendered a great deal of research in the atmospheric sciences. One common measure of convective energy used in many studies is the convective available potential energy (CAPE), the vertically integrated parcel buoyant energy ( Moncrieff and Miller 1976 ). CAPE is most frequently used as a forecasting tool for gauging severe thunderstorm likelihood since it

Full access
Allison T. LaFleur
,
Robin L. Tanamachi
,
Daniel T. Dawson II
, and
David D. Turner

1. Introduction Tornadoes in the southeast (SE) region of the United States can occur under different conditions than are typically seen in the Southern Great Plains (SGP) region. For instance, in the SE United States, tornadic storms have been observed to form and persist when analyzed CAPE is less than 500 J kg −1 provided sufficient shear is also present; this is the so-called “high shear, low CAPE” (HSLC) regime ( Sherburn and Parker 2014 ; Anderson-Frey et al. 2016 ; Sherburn et

Restricted access
Vince Agard
and
Kerry Emanuel

spatial extent is too small for them to be resolved by general circulation models. This difficulty is exacerbated in continental convective environments, where, unlike for oceanic convection, the atmosphere cannot be considered to be in radiative–convective equilibrium. Therefore, climate research on these severe local storms often focuses on the environments in which severe local storms are formed. Convective available potential energy (CAPE) and deep-layer vertical wind shear are two important

Full access
Ziwei Wang
,
James A. Franke
,
Zhenqi Luo
, and
Elisabeth J. Moyer

1. Introduction Convective available potential energy (CAPE) is an integral quantity of buoyancy in the convective layer ( Moncrieff and Miller 1976 ) and is considered as a key parameter in convection initiation and development. Closely linked to updraft strength and storm intensity, CAPE provides a way to understand the potential threat of some high-impact weather events such as thunderstorms, hail, and tornadoes. Brooks et al. (2003) propose a combination of CAPE and bulk wind shear as a

Full access
W. M. De Kock
,
R. C. Blamey
, and
C. J. C. Reason

1. Introduction The south Western Cape of South Africa (see Fig. 1 ), like other Mediterranean climate regions (southwestern Western Australia, southeastern South Australia, southern Europe, Morocco, central Chile, and California) is mainly a winter rainfall region. Containing South Africa’s second-largest city of Cape Town, it occupies a small but highly economically and agriculturally productive part of the country, which apart from this region, is summer rainfall dominated. However

Full access
Philip Tuckman
,
Vince Agard
, and
Kerry Emanuel

air has abundant convective available potential energy (CAPE), sufficiently small convective inhibition (CIN), adequate wind shear, and a trigger to initiate convection ( Bluestein 2007 ). The favorability of environments for severe convection (e.g., Grams et al. 2012 ), and the climatology of CAPE and CIN have also been studied (e.g., Riemann-Campe et al. 2009 ). Recently, this research has expanded to investigate the effect of climate change on severe convective events. Results suggest more

Open access
Callyn Bloch
,
Robert O. Knuteson
,
Antonia Gambacorta
,
Nicholas R. Nalli
,
Jessica Gartzke
, and
Lihang Zhou

potential energy (CAPE) is a well-established measure of buoyancy-driven atmospheric instability that is computed from vertical profiles of temperature and water vapor ( Blanchard 1998 ; Doswell and Rasmussen 1994 ; Holley et al. 2014 ). CAPE is important in forecasting severe weather, and is also used to derive other severe weather parameters including the bulk Richardson number (BRN), the significant tornado parameter (STP), and the supercell composite parameter (SCP). ( Bunkers et al. 2002

Full access