During the period from 9 to 11 November 2013, an explosive cyclone (EC) occurred over the Japan Sea-Okhotsk Sea. This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward. It had a minimum sea level pressure of 959.0 hPa, a significant deepening rate of central pressure of 2.9 Bergeron, and a maximum instantaneous wind speed of 42.7 m s −1. This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting (WRF) modeling results. The evolutionary processes of this EC were examined by using Final Analyses (FNL) data, Multi-Functional Transport Satellites-1R (MTSAT-1R) data, upper observation data and surface observation data. WRF-3.5 modeling results were also used to examine the development mechanism of this EC. It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.