Establishment of the Global Positioning System (GPS) and recent advancements in sonde windfinding have resulted in development of the NCAR GPS sonde. The GPS sonde's fine time/height resolution and fall characteristics are well suited to extend our knowledge of the detailed kinematic and thermodynamic structure within the boundary layer. It is important to understand these observations within the context of comparisons to nearby conventional surface measurements as well as past research based on aircraft and surface measurements. Sonde measurements gathered in mature hurricanes during the 1997 hurricane season have provided new insights on the vertical variation of winds in tropical cyclones (see abstract by Franklin and Black), but also have limitations that make it difficult to interpret low level variability in wind profiles. In this paper GPS sonde surface wind and thermodynamic measurements from Hurricane Danny of 1997 and Tropical Storm Josephine of 1996 are compared to nearby buoy and C-MAN measurements. Sonde wind profile ratios of surface (10 m) to higher level winds are compared to those determined from aircraft overflights of NOAA buoys. We investigate characteristics of the PBL / mixed layer humidity and thermodynamic structure and the relationship between the eyewall mixed layer depth and surface wind speed. Possible causes of variability in low level wind profiles are described along with wind engineering implications. Finally a method for estimating a surface wind from the PBL mean sonde wind is studied as an alternative to the more variable 10 m sonde wind, for use in real-time analysis efforts