Mission Plan :

Extratropical transition experiment. Depart MacDill 10:00 AM EDT, perform a Figure-4 in the transitioning storm, then synoptic drops to the northeast, landing at Portsmouth International Airport, NH at 6:00 PM EDT. Drop at center, radius of maximum winds, and endpoints of the Figure-4. AXBTs released along forecast flight track.

Mission Summary :

Took off from MacDill at 1434 UTC. Reached the IP at 1650, and began the Figure-4. Ophelia had a very tight circulation with radius of maximum winds about 3 km. Convective structure was asymmetric, with nearly all convection to the north and northeast of the center. However, convection was very strong with echoes on LF > 50 dBz. The system looked more like a supercell than a tropical cyclone at the time.

Finding the center was difficult on both passes because of the tiny size and because of moderate turbulence in clear air approaching the center. Turbulence disappeared in cloud, contrary to usual practice. Both passes were completed after much hunting and pecking, but this might be why the radar analysis software did not work during this mission.

SSTs from BTs along the flight track ranged from 26.2°C to 23.8°C to 25.2°C to only 16°C just southwest of Yarmouth, NS. Only one dropwindsonde failed to have a launch detect.

A warm core remained in the system as it continued to traverse the warm waters of the Gulf Stream, but cool waters ahead meant that transition would commmence soon. The rain shield to the northeast was barely evident on this day, and the signature looked symmetric on satellite.

PDF plots of drop data

Problems :

Problems were encountered using the x-chat system which repeatedly went down. Despite entering comments, nobody else saw the majority. Also, as stated above, the radar analysis software did not work on the two passes. One dropwindsonde needed to be FTPed to the workstation from the AVAPS station.