Status: Finalised Material from: Linus, Mohamed, Tung


 


Picture

1. Impact

The category 2 tropical cyclone DAMREY hit Vietnam on 3-4 November causing the loss of 60 lives and significant economical damages. Strong wind gusts (up to 140 KM/h) and heavy rainfall (more than 1000mm/48h) effected most of the country. The amounts of rain were significantly enhanced when the cyclone crossed the elevated orography in the east of the country.  The track of DAMREY was consistent in the IFS forecasts but the intensity was significantly under-predicted as indicated by official reports and in-situ observations. 

2. Description of the event


3. Predictability

  

3.1 Data assimilation

 

Surface pressure statistics around DAMREY on 04/11/2017 00Z

3.2 HRES

(left) Observed 48h accumulated precipitations VT:03/11/2017 00 UTC to 05/11/2017 00UTC
(Right) Short range HRES forecast showing 48h accumulated precipitations VT:03/11/2017 00 UTC to 05/11/2017 00UTC

3.3 ENS


Postage maps showing 48h accumulated rainfall initialised from 01/11/2017. Valid 03/11/2017 00 UTC to 05/11/2017 00UTC


(Left) Verification of Min pressure of DAMREY. Forecast based on 31/10/2017 00Z
(Right) Verification of Min pressure of DAMREY. Forecast based on 02/11/2017 00Z

The plots below show EFI and SOT for 3-day rainfall on 3-5 November.



3.4 Monthly forecasts

The plots below show the weekly precipitation anomaly for 30 October-5 November from monthly forecasts.

The plots below show the tropical cyclone strike probability for the week 30 October-5 November from 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


6. Additional material