TITLE

The Surprising Role of Orography in the Initiation of an Isolated Thunderstorm in Southern England

AUTHOR(S)
Lean, Humphrey W.; Roberts, Nigel M.; Clark, Peter A.; Morcrette, Cyril
PUB. DATE
September 2009
SOURCE
Monthly Weather Review;Sep2009, Vol. 137 Issue 9, p3026
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Many factors, both mesoscale and larger scale, often come together in order for a particular convective initiation to take place. The authors describe a modeling study of a case from the Convective Storms Initiation Project (CSIP) in which a single thunderstorm formed behind a front in the southern United Kingdom. The key features of the case were a tongue of low-level high θw air associated with a forward-sloping split front (overrunning lower θw air above), a convergence line, and a “lid” of high static stability air, which the shower was initially constrained below but later broke through. In this paper, the authors analyze the initiation of the storm, which can be traced back to a region of high ground (Dartmoor) at around 0700 UTC, in more detail using model sensitivity studies with the Met Office Unified Model (MetUM). It is established that the convergence line was initially caused by roughness effects but had a significant thermal component later. Dartmoor had a key role in the development of the thunderstorm. A period of asymmetric flow over the high ground, with stronger low-level descent in the lee, led to a hole in a layer of low-level clouds downstream. The surface solar heating through this hole, in combination with the tongue of low-level high θw air associated with the front, caused the shower to initiate with sufficient lifting to enable it later to break through the lid.
ACCESSION #
44216847

 

Related Articles

  • Assimilation of Lightning Data Using a Nudging Method Involving Low-Level Warming. Marchand, Max R.; Fuelberg, Henry E. // Monthly Weather Review;Dec2014, Vol. 142 Issue 12, p4850 

    This study presents a new method for assimilating lightning data into numerical models that is suitable at convection-permitting scales. The authors utilized data from the Earth Networks Total Lightning Network at 9-km grid spacing to mimic the resolution of the Geostationary Lightning Mapper...

  • Summertime Convective Storm Environments in Central Arizona: Local Observations. Wallace, Clinton E.; Maddox, Robert A.; Howard, Kenneth W. // Weather & Forecasting;Dec99, Vol. 14 Issue 6, p994 

    The daily evolution of local surface conditions at Phoenix, Arizona, and the characteristics of the 1200 UTC sounding at Tucson, Arizona, have been examined to determine important meteorological features that lead to thunderstorm occurrence over the low deserts of central Arizona. Each day of...

  • An Orography-Associated Extreme Rainfall Event during TiMREX: Initiation, Storm Evolution, and Maintenance. Xu, Weixin; Zipser, Edward J.; Chen, Yi-Leng; Liu, Chuntao; Liou, Yu-Chieng; Lee, Wen-Chau; Jong-Dao Jou, Ben // Monthly Weather Review;Aug2012, Vol. 140 Issue 8, p2555 

    This study investigates a long-duration mesoscale system with extremely heavy rainfall over southwest Taiwan during the Terrain-influenced Monsoon Rainfall Experiment (TiMREX). This mesoscale convective system develops offshore and stays quasi-stationary over the upstream ocean and southwest...

  • Cloud microphysical processes associated with the diurnal variations of tropical convection: A 2D cloud resolving modeling study. Shouting Gao; Fan Ping; Xiaofan Li // Meteorology & Atmospheric Physics;Jan2006, Vol. 91 Issue 1-4, p9 

    Cloud microphysical processes associated with the diurnal variations of tropical convection are investigated based on hourly data from a 2D coupled ocean-cloud resolving atmosphere simulation. The model is forced by the large-scale vertical velocity and zonal wind derived from TOGA COARE for a...

  • Thermally Forced Convection over a Mountainous Tropical Island. Wang, Chun-Chih; Kirshbaum, Daniel J. // Journal of the Atmospheric Sciences;Jun2015, Vol. 72 Issue 6, p2484 

    Observations from the Dominica Experiment (DOMEX) and cloud-resolving numerical simulations are used to study a thermally forced convection event over the Caribbean island of Dominica on 18 April 2011. A clear diurnal cycle of island thermal forcing and cumulus convection was observed, with...

  • Formation of the Convective Lines off the Mountainous Coast of Southeastern Taiwan: A Case Study of 3 January 2004. Cheng-Ku Yu; Ying-Hsun Hsieh // Monthly Weather Review;Sep2009, Vol. 137 Issue 9, p3072 

    Convective lines frequently occurring off the mountainous coast of southeastern Taiwan under weakly synoptically forced weather conditions are one of the most well-known mesoscale phenomena in Taiwan. These lines usually develop close to the coast but frequently can also be observed well...

  • Diabatic divergence profiles in Western Pacific Mesoscale convective systems. Mapes, Brian E.; Houze Jr., Robert A. // Journal of the Atmospheric Sciences;5/15/95, Vol. 52 Issue 10, p1807 

    Reports on the diabatic divergence profiles in Western Pacific mesoscale convective systems. Heating in the atmosphere as an expression of diabatic divergence; Expression of convective features; Observations in the purl dataset; Consequences of the heating profile of convection; Illustrations...

  • A Climatology of Fatal Convective Wind Events by Storm Type. Schoen, Joseph M.; Ashley, Walker S. // Weather & Forecasting;Feb2011, Vol. 26 Issue 1, p109 

    There are still hundreds of casualties produced by thunderstorm hazards each year in the United States despite the many recent advances in prediction and mitigation of the effects of convective storms. Of the four most common thunderstorm hazards (wind, hail, flooding, and lightning), convective...

  • Mesoscale modeling of lake effect snow over Lake Erie -- sensitivity to convection, microphysics and the water temperature. Theeuwes, N. E.; Steeneveld, G. J.; Krikken, F.; Holtslag, A. A. M. // Advances in Science & Research;2010, Vol. 4, p15 

    The article offers information on the study which evaluates the capacity of the fifth generation mesoscale model (MM5) and weather research and forecasting (WRF) for lake effect snow (LES) over Lake Erie and Buffalo in New York. It aims to identify the lake's sensitivity to microphysics,...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics