The wind structure associated with convective features along the inner edge of the hurricane eyewall

During the 1999 Atlantic hurricane season, the Hurricane Research Division (HRD) of NOAA conducted flight segments along the inner edge of the hurricane eyewall as part of research missions with the NOAA WP-3D aircraft. During these flight segments in major hurricanes Bret and Floyd, the aircraft operated at ~4000 m altitude and flew upwind just along the visible edge of the eyewall while releasing two to three GPS dropwindsondes in rapid succession. Airborne radar reflectivity data from the horizontally scanning, lower-fuselage radar system and reflectivity and Doppler data from the vertically scanning tail system were also collected during the flights. A combination of the radar data and the observations from the GPS dropsondes are used to investigate the complex wind structure that appear to be associated with convective features along the inside edge of the eyewall.

Observations from GPS dropsondes released in the hurricane core region have revealed multiple, low-level wind maxima. These wind maxima are most pronounced in the hurricane eyewall, particularly near the inner edge. The wind structure and variability seems to be associated with individual convective features containing strong up- and downdrafts. This paper concentrates on the horizontal and vertical wind structures observed with the dropsondes as they relate to convection observed with airborne radar systems during the unique flight patterns along the inner edge of the hurricane eyewall. A companion paper (Dodge et al. 2001) will present windfields of the hurricane eyewall from dual-Doppler analyses of airborne radar data collected during these flight segments.