Status:Finalized Material from: Linus, Tim, Florence

Discussed in the following Daily reports: -

1. Impact

On the 25 February (late afternoon), south-west France was hit by a squall line bringing heavy showers and wind gusts.

2. Description of the event

A presentation from Meteo-France about the event can be found here (provided by Marc Tardy from the Forecast Department at Meteo-France).


The satellite image above shows the convective cell (and the end of the arrow).

The figure above shows the maximum wind gusts for this day. Unfortunately, this event did not hit any of the stations we (ECMWF) have available for verification.


3. Predictability

 

3.1 Data assimilation

 

3.2 HRES

1-hour precipitation and MSLP
12z+4h
12z+5h
12z+6h
12z+7h
12z+8h

The figures above show the 1-hour accumulated precipitation and MSLP for the forecast from 25 February 12 UTC and forecast steps 4, 5, 6, 7 and 8 hours. Here one can see an intense convective system in southern France.

The figure above shows the 24 hour maximum wind gusts from the same forecast as the 1-hour precipitation. Here we do not see any strong wind gusts connected to the convective system.

3.3 ENS


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

  • The strong wind gusts seems to have been missed by the HRES forecasts.
  • A convective system seems to be present in the forecast, why not any gusts?