HAGIBIS (20W.2019) > FAXAI (14W.2019)?
intensity-wise no...strength-wise YES!
Mike Fiorino
21 October 2019
0330 UTC
In my September FAXIA-BLOG-POST I concluded this was the strongest typhoon to hit Tokyo, but now I wonder if typhoon HAGIBIS that struck Tokyo was stronger?
The first Japan Times article I read (shortly after landfall) drew comparisons to typhoon IDA of 1958, but the bigger difference vis-a-vis FAXAI was the horrendous rain and severe flooding.
My choice of 'strongest' typhoon to hit Tokyo was rather poor in hindsight...I should have said 'most intense' as in the TC's maximum surface wind speed. Let's compare the JTWC working best track for both storms around landfall (using 35.7N 139.7E as the latitude/longitude of Tokyo)
FAXAI 14W.2019:
HAGABIS 20W.2019:
The closest 6-h best track position for HAGIBIS has an intensity of 75 kts whereas FAXAI was at 90 kts as highlighted above... Thus, FAXAI was more intensity... However, the mean radius of 34 kt winds (sometimes used as a measure of TC strength) or R34 for HAGAIS was 289 nmi but for FAXAI was 94 nmi. Thus, HAGIBIS was much stronger!!!
The plot below gives a histogram of mean R34 in WESTAC using JTWC best track data 2009-2019:
Focus on the green bars -- the distribution for analysis time (or 'tau 0') for all verifiable positions. The mean is 107 nm and the median 101 nmi. R34 > 250 nmi is very rare and HAGIBIS at this time was almost record setting!!!
In terms of Integrated Kinetic Energy (IKE - Powell, M. D. and T. A. Reinhold, 2007: Tropical cyclone destructive potential by integrated kinetic energy. Bull. Amer. Meteor. Soc., 87, 513-526) based on the symmetric wind profile in Fiorino and Elsberry 1989: Some aspects of vortex structure related to tropical cyclone motion, J. Atmos. Sci, 46, 976-990 that only requires intensity Vmax and R34 we find:
FAXAI: Vmax: 90.0 kts; R34: 94 nmi -- IKE: 50 Tj
HAGIBIS: Vmax 75.0 kts; R34: 289 nmi -- IKE: 273 Tj
or HAGIBIS was around 5.5X stronger than FAXAI
The only (small 😢) saving grace for Japan was that HAGIBIS was moving quickly at 20 kts at landfall and accelerating during extra-tropical transition whereas FAXAI was slower at 12 kts and more tropical
The much larger rainfall impact of HAGIBIS is partly explained by the massive size of the circulation. Another reason is that the storm was becoming extra-tropical as it moved over Honshu.
2019 will certainly be historical for Japan: the year of the most intense typhoon (FAXAI) to strike Tokyo and the strongest ever storm HAGIBIS to impact Tokyo, the Kanto plain the all of northern Honshu. All I can say is WOW and thoughts and prayers for Japan.
The first Japan Times article I read (shortly after landfall) drew comparisons to typhoon IDA of 1958, but the bigger difference vis-a-vis FAXAI was the horrendous rain and severe flooding.
My choice of 'strongest' typhoon to hit Tokyo was rather poor in hindsight...I should have said 'most intense' as in the TC's maximum surface wind speed. Let's compare the JTWC working best track for both storms around landfall (using 35.7N 139.7E as the latitude/longitude of Tokyo)
FAXAI 14W.2019:
2019090812 14W.2019 100 952 34.0N 139.1E 129 65 350.5 12.7 B lf: 0.00 2019090818 14W.2019 090 958 35.3N 139.7E 94 49 14.1 11.9 B lf: 0.69 2019090900 14W.2019 075 982 36.3N 141.0E 78 36 34.0 13.9 B lf: 0.18
HAGABIS 20W.2019:
2019101206 20W.2019 085 951 33.7N 138.2E 241 141 19.3 15.4 B lf: 0.00 2019101212 20W.2019 075 960 35.6N 139.4E 289 125 24.8 19.8 B lf: 0.69 2019101218 20W.2019 065 970 38.4N 142.1E 289 115 33.8 28.3 B lf: 0.04
The closest 6-h best track position for HAGIBIS has an intensity of 75 kts whereas FAXAI was at 90 kts as highlighted above... Thus, FAXAI was more intensity... However, the mean radius of 34 kt winds (sometimes used as a measure of TC strength) or R34 for HAGAIS was 289 nmi but for FAXAI was 94 nmi. Thus, HAGIBIS was much stronger!!!
The plot below gives a histogram of mean R34 in WESTAC using JTWC best track data 2009-2019:
Focus on the green bars -- the distribution for analysis time (or 'tau 0') for all verifiable positions. The mean is 107 nm and the median 101 nmi. R34 > 250 nmi is very rare and HAGIBIS at this time was almost record setting!!!
In terms of Integrated Kinetic Energy (IKE - Powell, M. D. and T. A. Reinhold, 2007: Tropical cyclone destructive potential by integrated kinetic energy. Bull. Amer. Meteor. Soc., 87, 513-526) based on the symmetric wind profile in Fiorino and Elsberry 1989: Some aspects of vortex structure related to tropical cyclone motion, J. Atmos. Sci, 46, 976-990 that only requires intensity Vmax and R34 we find:
FAXAI: Vmax: 90.0 kts; R34: 94 nmi -- IKE: 50 Tj
HAGIBIS: Vmax 75.0 kts; R34: 289 nmi -- IKE: 273 Tj
or HAGIBIS was around 5.5X stronger than FAXAI
The only (small 😢) saving grace for Japan was that HAGIBIS was moving quickly at 20 kts at landfall and accelerating during extra-tropical transition whereas FAXAI was slower at 12 kts and more tropical
The much larger rainfall impact of HAGIBIS is partly explained by the massive size of the circulation. Another reason is that the storm was becoming extra-tropical as it moved over Honshu.
2019 will certainly be historical for Japan: the year of the most intense typhoon (FAXAI) to strike Tokyo and the strongest ever storm HAGIBIS to impact Tokyo, the Kanto plain the all of northern Honshu. All I can say is WOW and thoughts and prayers for Japan.
