Shell Mound wrote:1900hurricane,
Excellent investigation and write-up! If I may ask: what are your personal estimates for the peak intensity of PARMA (2009)?
Parma '09 probably got pretty deep as well. It too had about an 18 hour period of apparent extreme rapid intensification (18 hours seems to be a fairly common interval for such deepening rates I've found, at least for small eye cases). However, there are some factors that give me pause about it approaching maximum observed deepening rates. First off, it doesn't have textbook dual outflow channels that my Hagibis/Patricia/Wilma/Forrest hyperbomb grouping had. Related to that, but Parma was also embedded in moderate/strong easterly flow aloft (primarily due to the strong upper level ridge to the north and twin developing Super Typhoon Melor to the east), which introduced some shear to the system.
Environmentally, Super Typhoon Judy '79 may be a similar match. The shear direction is different (north with Judy vs east with Parma), but both were limited to one outflow channel. This is probably a big reason Judy did not approach maximum observed deepening rates for its eye size, which aircraft reconnaissance observed to be of similar size to the other mentioned cases. Judy did eventually reach the sub 890 mb pressures, but it also persisted longer than Parma did, maintaining the small eye for longer than just the potential extreme rapid intensification period. Because Parma collapsed so quickly after its intensification phase (which I mentioned previously in the thread here
), it makes it a particular difficult case to estimate. If I had to throw a number on it, I'd probably estimate Parma deepening to about 900 mb or so by roughly 2200Z September 30th, 2009, but that is not much more than a shot in the dark estimate.
Below are some images of Judy '79 from the UNCA IBTrACS website
, from 00Z and 21Z September 19th, 1979, respectively. These two times correspond in turn to the end of the most rapid deepening and point of lowest observed pressure. I've also included Judy's recon trace which I put together with my interpolated best track pressure values overlaid.