Hurricane Hanna (2008) Track Deflection and Rapid Intensity Change: An Observational and Numerical Study

Tropical cyclone (TC) track deflection and looping motion have been of great interest because looping tracks are usually associated with extended periods of local heavy precipitation and strong surface winds. These storm tracks often presented a challenge for forecasters. In the current work we study the track deflection of Hurricane Hanna during the 2008 Atlantic hurricane season. Here we refer to a rapid change in the track as a deflection. Hanna moved along a northwestward track during the first 5 days after its genesis on 28 September. However, it made a sharp turn to the south on 1 September and continued to move southward over the next two days. A cyclonic looping track was formed near the Caicos Islands after Hanna finished a northward maneuver from 3-4 September. During this period, Hanna also exhibited rapid intensity change, quickly developed on 1 September from a tropical storm to a hurricane, and then weakened at a even more rapid pace back to tropical storm strength the following day. The official forecasts and dynamic model guidance had large forecast errors for both Hanna's track and intensity around the track deflection period. Detailed analysis of possible dynamic and physics processes associated with Hanna track deflection and rapid intensity change will be presented at the conference.