As Tropical Storm Erika was 800 km east of the Leeward Islands a NOAA P-3 and G-IV mission collected airborne Doppler radar data to use in initializing and evaluating model guidance and a Saharan Air Layer Experiment (SALEX) mission.
The figure below depicts the aircraft flight track (P-3: yellow line; G-IV: red line) superposed on the real-time lower fuselage radar and visible satellite imagery.
Included here you see images of the horizontal winds within 180 km of Erika sampled from the tail Doppler radar on the P-3 and within 350 km of Erika from the G-IV aircraft during the evening of 25 August 2015. These images are at three altitudes (1 km, 3 km, and 6 km) and are a composite of winds from the P-3 and G-IV Doppler patterns around Erika. Also plotted on each analysis are the locations of dropsondes deployed by the P-3 and G-IV (plotted using standard station symbols). These analyses show that Erika had a very asymmetric distribution of precipitation at all altitudes, with the bulk of the precipitation primarily in the southeastern quadrant of the storm, particularly at 3- and 6- km altitude. There is indication of a very small circulation center at 1- and 3-km altitudes, with strong winds 15-20 km northeast of the circulation center, but with strongest winds extending 100-180 km to the east and northeast of the center. At 6-km altitude there was an indication of a circulation center in the heavy precipitation 125-150 km southeast of the 1-km altitude circulation center, indicative of very strong west-northwesterly shear of the horizontal wind over the low-level center. The G-IV analyses show very strong southerly flow at all altitudes into the circulation from 180-250 km southeast of the low-level center and into the large precipitation area southeast of the center, fueling the deep convection there.
All the Tropical Storm Erika radar composites at 0.5-km height resolution are available at: http://www.aoml.noaa.gov/hrd/Storm_pages/erika2015/radar.html