Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

 Status:Ongoing analysis Material  Status: Finalised Material from: Linus, Esti, Ivan

...


 

Show If
spacePermissionINTRA

Discussed in the following Daily reports:

2017-08-18

2017-08-21

2017-08-23

2017-08-25

2017-08-28



1. Impact

Early on 26 August tropical cyclone Harvey made landfall on the TExas coast between Corpus Cristi and Rockport. Later the cyclone became stationary for 3 days (check) and a huge amount of rainfall fell over the region (locally more than 1000 mm) and caused massive floodings in e.g Houston. We do not yet know the final result from the cyclone.

2. Description of the event

...

The series of plots below shows 3-day accumulated precipitation (26 August 00z to 29 August 00z) and MSLP valid 27 August 12z from HRES forecasts. The first plot is the accumulation from NEXRAD for the same period.

Image Added

The plot below shows the evolution of the central pressure in Best Track (black) and HRES forecasts with different initial times. The forecasts before 25 August missed the rapid intensification the day before landfall. Also note how the forecast from 24 August 12z kept the intensify for a long time, probably because the cyclone stalled closer to the coast as seen above.

...

The figure below includes 3-day EFI and the precipitation from NEXRAD, valid 25 August 00z to 28 August 00z..

Image AddedImage Removed

The plot below shows the ensemble evolution for 72-hour precipitation for Houston 26-29 August. The ensemble distribution is shown in blue box-and-whisker and HRES in red dot. The model climate is shown in red box-and-whisker positioned on 26 August.

...

4. Experience from general performance/other cases

...


5. Good and bad aspects of the forecasts for the event

  • Early capturing Good early prediction of the risk for moving the cyclone to move into Gulf of Mexico
  • Picked The forecasts picked up the risk the risk for heavy rainfall around Houston (especially HRES) from around 21-22 August . Model (4 days before the landfall). HRES generated more than 1000 mm/72h locally.
  • Did The forecasts did not predict predicted the rapid intensification before landfallit started. However, RI is well known to be unpredictable, and I do know how much we should expect from a global model here.

6. Additional material