Special Sensor Microwave/Imager data are used to examine the day-to-day variability of wind speed and precipitable water during the passage of an intraseasonal oscillation. First, SSM/I precipitable water and wind speed algorithms are evaluated for the tropical western Pacific Ocean. The algorithm by Alishouse for retrieving precipitable water vapor retrieves precipitable water values that compare well with island radiosonde observations, but the wind speeds retrieved using the algorithm by Goodberlet et al. compare with buoy wind speeds only marginally. A revised wind speed algorithm, based on regression with buoy wind speeds, is derived for use in this region. During the intraseasonal oscillation, anomalously high values of precipitable water, with maximum amplitude at 10¿S, accompany the movement of convection eastward. Anomalously high wind speeds are found to the west of the convection and accompany its movement east. Differences of up to 20% are found along 10¿S between the means of daily latent heat flux and U*3 values and the 60-day mean of these quantities. This implies that high frequency variability must be explicitly accounted for in diagnostics and modeling of air-sea interaction in the western equatorial Pacific Ocean.