As Tropical Storm Erika passed south of Puerto Rico and Hispaniola (see the black lines outlining the two islands near the top of of analyses) a NOAA P-3 mission collected airborne Doppler radar data to use in initializing and evaluating model guidance.
The figure below depicts the aircraft flight track (P-3: yellow line) superposed on a visible satellite imagery.
Included below you see images of the horizontal winds within 180 km of Erika sampled from the tail Doppler radar on the P-3 aircraft during the early morning of 27 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 Doppler pattern around Erika. Also plotted on each analysis are the locations of dropsondes deployed by the P-3 (plotted using standard station symbols). These analyses show that Erika maintained a very asymmetric distribution of precipitation at all altitudes, with the bulk of the precipitation primarily in the eastern semicircle of the storm at all altitudes. There is slight indication of a very broad circulation center at 1- and 3-km altitudes, with the strongest winds 100 km east of the circulation center, and extending to 180 km to the east and northeast of the center onto the south coast of Puerto Rico. At 3-km altitude the strongest winds 150 -180 km east of the circulation center. At 6-km altitude there was still an indication of a circulation center in the heavy precipitation 100-125 km east-southeast of the 1-km altitude circulation center, indicative of very strong west-northwesterly shear of the horizontal wind over the low-level center.
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.