This project implements an algorithm to estimate drift of the dropsondes in the data assimilation system of the operational Hurricane Weather Research and Forecasting model. With the help of JTTI funds this dropsonde drift algorithm was operational tested and implemented in the National Weather Service (NWS) operations. NWS is now able to assimilate more dropsonde observations in the NWS operational hurricane forecast model. This, along with the other upgrades, resulted in more than 10% improvement in the skill of tropical cyclone track and intensity forecasting.