A modeling study on Sumatra squall lines using WRF

Monday, 15 December 2014
Chun Fung LO, Centre for Climate Research Singapore, Singapore, Singapore
Sumatra Squall Line (SSL) is a tropical squall line system that usually forms over Sumatra at night and then sweeps towards the west coast of Peninsular Malaysia and Singapore in the early morning. SSL is one of the dominant rain-bearing systems in the region, particularly between April and November each year. In this study, we examine a series of short term (<24 hours) numerical experiments using Weather Research and Forecasting (WRF) model, conducted under a monthly long high occurrences period in August 2013. We examine the predictability and evaluate the WRF performance. By examining over 20 SSL cases, we identify the general features of SSL and discuss its formation and propagation mechanisms. Through inter-comparison of simulations driven by GFS and ECMWF re-analyses, we also discuss the triggering effects of large scale atmospheric conditions on SSL.