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 Status:Ongoing analysis Material from: Linus, Ivan, Ervin

 

 


Picture

1. Impact

18-20 April north-western Europe experienced un-seasonally warm temperatures and many April records were broken.


2. Description of the event


The plot below shows the anomalies (shade) and full field (contour) for z500 and t850 for 18-20 April. A strong ridge was centred over northern Germany.

The plot below shows the time-series of daily maximum and minimum temperatures for Reading (from University of Reading).


3. Predictability

  

3.1 Data assimilation

 

3.2 HRES

The plot below shows 2-metre temperature for Reading from HRES (red) and nearby observations(black). The forecast clearly missed the daily maximum temperatures during the event.


The plot below shows mean error for daily maximum temperature in 3-day forecasts from 15 to 19 April. The underestimation of the daily maximum temperatures where wide-spread over western Europe.

The plot below shows the evolution of various parameters in HRES from 19 April.



3.3 ENS

The plots below show the EFI and SOT for 2-metre temperature valid 18-20 April from forecast with different initial dates. Also the forecast initialised on 12 April (last figure), showed a relatively strong signal over western Europe.


The plot below shows the evolution of forecasts for 2-metre temperature in Reading on 19 April 12UTC of the ensemble (blue) and HRES (red dot).



3.4 Monthly forecasts

The plot below shows the analysis (first panel) of the 2-metre temperature weekly anomalies and the monthly forecasts (subsequent panels).

The plot below shows the same as above but for MSLP.


3.5 Comparison with other centres


4. Experience from general performance/other cases

 

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

  • Good week 2 signal in the ensemble
  • Problems with daily maximum temperatures also in the shortest forecasts

6. Additional material