Data collected during several marine expeditions are used to investigate synoptic-scale disturbances in the Tropical Western Pacific. Measurements made on board the NOAA ship Ron Brown reveal westward propagating organized structures moving parallel to the equator. It is found that the true wind direction oscillates between about 60 and 120 deg with a period of 4 - 5 days. Similar 4 – 5 day wind oscillations were also observed in the data obtained by radiosonde launched from the ship. Eddy-correlation measurements made at height 17.7 m above the sea surface show that meridional wind speed oscillations result in similar variations of the wind stress exerted on the sea surface (for wind speed 4 – 8 m/s). Observations made between 2 S and the equator during the Nauru99 expedition show that Nauru Island effect has minimal impact on the observed meridional oscillations of the wind and the stress.