Propagation of Convective Systems Associated with Early Morning Precipitation and Different Northerly Background Winds over Western Java

Early morning precipitation (EMP) events occur most frequently during January and February over the northern coast of West Java are characterized by propagating systems originating from both inland offshore. The timing EMP is determined initial location, direction, speed precipitating system. This study explores processes that characterize such performing composite analysis real-case numerical simulations selected using Weather Research Forecasting (WRF) model with a cloud-permitting horizontal resolution 3 km. In analysis, classified according to strength northerly background wind (VBG), defined as 925 hPa meridional averaged an area covering western adjacent sea. We find under strong (SN) weak (WN) conditions, mainly induced system propagates sea land. For WN cases, however, propagate areas also play role. WRF suggest mechanisms akin cold pool propagation advection prevailing winds responsible for convection induces EMP, which explains dependence frequency on VBG. On basis simulations, we discuss roles breeze gravity waves in initiation convection.