Status: Ongoing analysis Material from: Linus, Zied, Tim
| Show If | ||||||
|---|---|---|---|---|---|---|
| ||||||
Discussed in the following Daily reports:
|
New Addition (4 Oct 2022): An examination of model performance for two ECMWF model cycles, centring on the fatal flash floods that occurred around the High Fens area of Germany / Belgium (by Tim Hewson).
1. Impact
On 14 July parts of western Germany and Belgium was hit by extreme rainfall, leading to flash-floods and rapid raise of the water in middle-sized rivers like Meuse. Approximately 200 people were killed in the event. Also Switzerland, France, the Netherlands, and Luxembourg was hit.
https://en.wikipedia.org/wiki/2021_European_floods
https://floodlist.com/europe/2021-floods-germany-forecast-warnings
2. Description of the event
The event started around 12 July with heavy rainfall in southern Germany and Switzerland. The rainfall moved later to the north on the north-western side of the upper-level trough.
The plots below show precipitation observations from DWD, shared via Twitter,
The evaluation evaluation below will be based on two regions and period: 3-day (12-14 July) in a box covering the extended Rhine valley (46.5N-52N, 5E-8.5E) and 1-day (14 July) centred on the Ardenne mountains (49.5N-51.5N, 6E-7.5E).
The plots below show analyses of z500 (contour) and T850 (shade) from 9 July 00UTC to 15 20 July 00UTC, every 24 hour. The rainfall was associated with an upper-level cut-off that moved from the west into central Europe. After the peak in rainfall on 15 July the feature moved further to the south-east and continued to produce heavy rainfall in southern Germany, Austria and the Balkans.
The plots below show analyses of MSLP and 6-hour forecasts of precipitation from 12 July 00UTC to 15 July 00UTC, every 12 hour.
...
The plot below shows the forecast evolution plot for 24-hour precipitation valid 14 July 06UTC - 15 July 06UTC in the box over the Ardennes. Observation – green, HRES –red, ENS CF – purple, ENS blue box-and-whisker, Model climate – red box-and-whisker. Triangle marks the maximum in the model climate based on 1200 forecasts. The wet signal started to appear on 9 July and grow gradually stronger. From 11 July all ensemble median was above 99th percentile and from 12 July about the model climate maximum.
The plots below show the crossing-point forecast (CPF) for 1-day precipitation 14 July, from different initial times.
12-14 July
The plots below show EFI for 3-day precipitation 12-14 July, from different initial times.
...