ABSTRACT This study examines the seasonality, spatial distribution and characteristics of mesoscale convective systems (MCSs) in the Philippines from 2001 to 2019. MCS frequency is at its highest during the boreal summer (JJA), which is driven by strong southwesterly monsoon winds transporting moisture into the region. During the transitional monsoon seasons (MAM and SON), MCS frequencies are lower due to the weaker large‐scale forcings. The lowest frequencies occur during the boreal winter (DJF) when the northerly cold surges and strong easterly moisture fluxes produce fewer but longer‐lived MCSs with intense precipitation. The diurnal cycle shows a land‐ocean contrast with land‐based MCSs peaking at noon to early afternoon, while oceanic MCSs initiate more gradually in the early morning, with their precipitation peaking in the early morning and late afternoon. Beyond seasonal and diurnal differences, intraseasonal oscillations modulate the MCSs in the Philippines. Both the active phases of Madden‐Julian Oscillation (MJO) and the Boreal Summer Intraseasonal Oscillation (BSISO) have been shown to enhance MCS activity in the Philippines.
Lagare et al. (Wed,) studied this question.