The potential applications of high-frequency microwave brightness temperature (TB) observations from polar-orbiting satellites to Hurricane Earl's rapid intensification forecasting is investigated. Specifically, TB observations from the Microwave Humidity Sounders (MHS) on board European MetOp-A and United States NOAA-15, 16, 18, 19 and MicroWave Humidity Sounder (MWHS) on board Chinese FY-3A were analyzed during the rapid intensification period of Hurricane Earl from August 29 to September 3, 2010. A 126-h model forecast initialized at 0000 UTC 29 August 2010 was made using the Hurricane Weather Research and Forecasting (HWRF) System. The HWRF system is a coupled system composed of the nonhydrostatic, two-way interactive, moving nest model and the three-dimensional Princeton Ocean Model (POM). The weak vortex at the initial time in GFS analysis was replaced by a 2D axisymmetric synthetic vortex. The track, intensity and size of model-simulated Hurricane Earl compared favorably with the best track data. The HWRF outputs of temperature, water vapor, hydrometeor profiles and surface winds were then used as inputs to the Community Radiative Transfer Model (CRTM) to produce TB simulations at MHS and MWHS frequencies for Hurricane Earl. Comparisons are made for the cloud structures of Hurricane Earl among MHS/MWHS TBs, airborne radar reflectivity and the HWRF model simulation. By relating the TBs with reflectivity, liquid water content (LWC) and ice water content (IWC) from both models and observations, the ability for MHS/MWHS to see through hurricane clouds was assessed. Insights on an effective use of high-frequency microwave cloudy radiances from multiple polar-orbiting satellites gained from this study will also be discussed.