Regarding Katrina, he is convinced Katrina was a Cat 4 at landfall at least in LA, and from the way he worded it, he probably meant MS as well. He said he can’t bring himself to believe that a 920 mb pressure would correspond to a Cat 3 intensity, since it is so far removed from the typical pressure/wind relationship. He believes the large size of the hurricane cannot fully explain this. He also believes that recon did NOT sample to top sustained winds in the cane, and overall he seemed very suspicious of the way NHC reduces flight-level winds to the surface. About Katrina’s storm surge, he thinks the large wind field cannot account for all of the storm surge height (although interestingly enough he did stress the importance of wind field size in storm surge at another time).
Another interesting thing he mentioned was about the upgrade of Andrew to Cat 5 status. He didn’t necessarily *criticize* the decision necessarily, but he seemed to think that the decision to upgrade solely based on a 90% reduction factor from the 162 kt flight-level wind was not enough justification. He views the lack of sufficient surface data as a big problem in determining hurricane intensities accurately…he pointed out the Cindy example, where it was upgraded solely based on flight-level and radar velocity data and not dropsondes. Interestingly enough, he mentioned that there are some mets (at the NHC?) who do NOT agree with Andrew’s upgrade, and mentioned one particular colleague who is VERY adamant about that…mentioned something about “taking it to the grave” or something lol.
Personally I disagree with his views, but I’ll let you guys comment on this.
Other things I remember:
-He thinks the NHC live and die by the models too much sometimes. The Ivan example was brought up, when the GFS (and the tropical models run off that) continually depicted it turning north way too early. Someone else brought up that the GFS had been underestimating the subtropical ridge before Ivan for the week before or so, and Dr. Lyons couldn’t understand why NHC would still go with the GFS in this case.
-Although overall forecast skill has improved, the skill for forecast the LANDFALL location within 24-36 hours has NOT improved at all in the past couple decades. This was pretty surprising to me. Ditto for intensity forecasting.
-He has been very successful in the past couple of years at anticipating rapid intensification cycles using a sort of flow-chart containing certain conditions. I wish I remembered to ask more about this, but the couple things I remember were an excellent outflow presentation and the presence of those outflow “spokes” that appear in the CDO, that indicate massive evacuation of the air in the upper levels.
-He believes coastal areas are over-evacuated. He says the only areas that should really be evacuated are storm-surge prone areas, and low-lying areas from freshwater flooding. Everyone else should basically stay and hunker down, because wind rarely kills anyone.
Anyways, it was a great experience meeting him, even if I do disagree with him. You can just feel his passion for what he does; he said he could talk about hurricanes and the like for hours and hours on end. It was really awesome just to meet someone who is so passionate about what they do.
Fire away with your thoughts…
