As AL92 passed just south of Hispaniola (visible outlined in black at the top of the images) the first NOAA P-3 mission collected airborne Doppler radar data to use in improving our understanding of tropical cyclogenesis, as well as for initializing and evaluating model guidance. Included here you will see images of the horizontal winds within about 150 km of the center of the disturbance sampled from the tail Doppler radar on the P-3 late on 12 September 2010. These images are at three altitudes, 1 km, 3 km, and 6 km, using a composite of winds from all three legs oriented northwest-southeast, east-west, and southwest-northeast. Wind, temperature and relative humidity from GPS dropsondes dropped from the P-3 are also visible at 1 and 3 km altitudes. Note the lack of a closed circulation and the northwest versus southeast asymmetry in the distribution of winds suggesting a very sharp trough oriented northeast-southwest in the flow at 1 and 3 km altitude changing to more light and variable winds at 6 km. AL92 appears to be developing a low-level circulation, however, the asymmetric distribution of wind and precipitation suggests that cyclogenesis is proceeding slowly.
Published on: September 14, 2010