Extreme vertical winds measured by dropwindsondes in hurricanes

We have presented a dataset of extreme updrafts sampled by GPS dropwindsondes. There are a limited number of samples (33) thus far and analysis of this data is still in the preliminary stage, so it is too early to draw broad conclusions. Still, there are some aspects of this data that clearly stand out. Firstly, every upsonde was found in a major hurricane, including 2 in category 3, 12 in category 4, and 19 in category 5. These extreme updrafts are therefore a phenomenon of the most intense hurricanes. Almost all of the upsondes were dropped within a few km of the radar eye/eyewall boundary. Falling into a presumably outward sloping eyewall, the upsondes generally encounter the extreme updrafts slightly to the eyewall side of the boundary. This appears to hold true over a wide range of eye sizes. There doesn't appear to be a relationship between upsonde locations and the direction of storm motion. There is a strong relationship between location and the shear vector however. Upsondes are almost all left of shear, with the majority in the downshear-left quadrant. Thus, it appears that shear plays a large role in determining the location of strong updrafts, despite the fact that all of these storms were very intense and apparently symmetric. Many of the upsondes also experienced extreme horizontal windspeeds, either concurrently with the extreme updrafts, or elsewhere in their trajectories. More than half of these experience windspeeds greater than 90m/s, and they represent about a third of all sondes with such strong horizontal winds. Preliminarily, it appears that these extreme updrafts may be associated with convective instability. One mechanism that could produce such instability is the transport of high theta-e air from the eye into the lower theta-e eyewall. This mixing appears to be occurring in Isabel on the 12 ^th. In turn, this mixing could be driven by mesovortices along the eye/eyewall interface. Further analysis of the data (including the sondes, flight level data, and radar) will help to determine if such mesovortices and mixing are present here. If so, this would support the theory that hurricanes may in some cases exceed their potential intensity. In the presence of substantial shear (as in many of these cases), it may allow hurricanes to remain more intense than they otherwise would be. It is anticipated that there will likely be additional upsondes present in storms from 2005 flown by the Air Force, whose data is not yet available as of this writing. Furthermore, this currently small dataset is expected to grow as intense storms continue to be sampled in the future.