 The progenitor to Typhoon Nanmadol was first noted by the Joint Typhoon Warning Center (JTWC) as an isolated cluster of thunderstorms roughly south-southwest of Pohnpei at 2200 UTC on November 27, 2004.With convection consolidating about a potential center of circulation, the Japan Meteorological Agency (JMA) classified the broad system as a tropical depression the following day.Rapid development of storms and organization ensued following classification, spurred by favorable conditions.