Accurate estimation of evapotranspiration (ET) over irrigated crops is highly desirable for optimal water management in arid lands. Recent research has shown that remote sensing observations of crop radiative temperatures can improve ET retrieval accuracies by extending point-based estimates into the spatial domain. When considered along with near surface meteorological data, these temperatures are indicative of instantaneous crop water status. Combining ET with a crop model allows these instantaneous estimates to be extended to daily time scales. Utilizing soil moisture, agronomic, and airborne multispectral remote sensing observations, crop water use is estimated at sub-meter scales with the DSSAT/CERES wheat growth model for a Maricopa, Arizona field experiment in 2005.