What happens to easterly waves during and after a tropical cyclone (TC) forms? How does their potential vorticity (PV) field evolve? This observational study led by graduate student Bryce Tyner examines the PV associated with easterly waves during the process of TC genesis.
Qualitatively, three types of evolution were defined. First, the most common one in which the wave PV axisymmetrizes and gets completely wrapped up into the TC. Second, less often, the TC cuts-off from the wave and the wave continues on. Third, rather rare, in which the the wave and the cyclone appear to co-exist. This may happen for a weak TC which goes from a wave to a TC and back to an “open wave”.
For more information, see the paper: Tyner and Aiyyer, 2013