Fujiwhara effect
The ITCZ-based depression which developed into Gwen was first noted on August 5 while south of Tehuantepec. Although a ship in the region reported winds and waves, a satellite picture revealed a cloud mass of amorphous quality. Although a little vortex in the region was visible, the system would show little development for 48 hours until, on August 7, stronger rotation and outflow were apparent in satellite imagery. The next day, a ship north of the center reported waves and winds. Data based on satellite images, and the ship report, were enough to upgrade the system to Tropical Storm Gwen. Around this time, the track of the newly named system was being affected by the stronger Fernanda to its west via Fujiwhara effect. Shortly thereafter, satellite photos showed an exposed atmospheric circulation in the northwest section of the storm with cloud cover lagging behind it, and the storm was downgraded to a depression on August 8. The circulation was completely exposed by the next day, and Gwen dissipated. The remnants of Gwen continued to interact with Fernanda until complete dissipation.