Status:Ongoing analysis Material from: Linus
1. Impact
Super-typhoon Yagi first made landfall on the Philippines on 2 September as a relatively weak system but intensified over South China Sea and reached a central pressure of 915 hPa on 5 September. The TC made landfall on Hainan on 6 September and again on Vietnam on 7 September. The remnant of the TC continued to the west and caused devastating rainfall in Myanmar.
""In Vietnam, over 241,000 houses were damaged and 296 people died, with 38 more missing; a majority of the casualties were caused by landslides. The remnants of Yagi caused catastrophic flooding and landslides in Myanmar, where 557 deaths and up to 10,000 more missing were reported.
""
(https://en.wikipedia.org/wiki/Typhoon_Yagi)
2. Description of the event
The evaluation of the rainfall will focus on 120-hour rainfall on 7 September 00UTC - 12 September 00UTC in a 1x1 degree box centred on Hanoi, Vietnam (21N, 106E).
The plots below show analyses of MSLP and 6 hour rainfall from 5 September 00UTC to 12 September 00UTC, every 12th hour.
3. Predictability
3.1 Data assimilation
The plot below shows the observation statistics for surface pressure from METAR ZJHK.
3.2 HRES
The plots below show 120-hour precipitation in observations (first plot) and concatenated short forecasts (second plot).
The plots below show 120-hour precipitation in ENS control forecasts with different lead times.
The plots below show 120-hour precipitation in DestinE 4.4km with different lead times.
The plots below show 120-hour precipitation in AIFS with different lead times.
The plots below show 120-hour precipitation in AIFS0-ENS member 1 with different lead times.
The plots below show 120-hour precipitation in 49r1 ENS member 1 with different lead times.
3.3 ENS
The plots below shows EFI for 5-day precipitation (7-11 September).
The plot below shows the forecast evolution plot for 120-hour precipitation around Hanoi.
Observation - green hourglass
Analysis - green dot
ENS control–red
ENS - blue box-and-whisker
AIFS - cyan dot
AIFS-ENS - grey box-and-whisker
Model climate – cyan box-and-whisker
Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1200 forecasts.
The plot below shows the same as above but with:
Observation - green hourglass
Analysis - green dot
ENS - blue box-and-whisker
ENS 49r1 - purple box-and-whisker
DestinE - evergreen dot
Model climate – cyan box-and-whisker
Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1200 forecasts.
The plots below show the tropical cyclone track for TC Yagi for the operational ECMWF forecasts from 6 September 00UTC (first plot) to 1 September 00UTC (last plot). The symbols shows the position on 6 September 00UTC (hourglass for BestTrack). HRES (red), ENS CF (blue), ENS PF (grey) and BestTrack (black). AIFS is included in green.
The plots below show the same as above but of 49r1 e-suite.
The plots below show the tropical cyclone intensity (central pressure - top, maximum wind -bottom) for TC Yagi for the operational ECMWF forecasts from 6 September 00UTC (first plot) to 1 September 00UTC (last plot). HRES (red), ENS CF (blue), ENS PF (grey) and BestTrack (black). AIFS is included in green.
The plots below show the same as above but of 49r1 e-suite.
3.4 Monthly forecasts
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Problem to capture the rapid intensification in the o-suite, better in the e-suite ensemble
- AIFS ensemble similar in capturing the signal for extreme rainfall over Vietnam, but with somewhat lower magnitude
- ENS control wetter than the majority of the ensemble members