Material from: Linus, Ervin

1. Overview

 On 10 September the coasts along the northern Adriatic was hit by torrential rainfall. Between 06Z and 18Z for example Rijeka recorded 152 mm,.

2. Analyses and Observations

2.1 Event Definition

We will focus on the 24-hour precipitation between 10 September 06UTC and 11 September 06UTC in a 0.5x0.5 centred on Rijeka in Croatia (45.2N, 14.6E)

2.2 Analyses

The plots below show analyses of MSLP and 6 hour rainfall from 8 September 00UTC to 11 September 00UTC, every 12th hour.

The plots below show analyses of T850 and z500 from 4 September to 11 September. While the flow is strong from south-west on 10-11 September the trough is to so strong.

2.3 Observations

2.4 Climatological perspective

3. Forecasts

3.1 Data assimilation and observation usage

3.2 Single Forecasts for the event based on 00UTC forecasts (defined in Section 2.1)

Observations and analysis for the event

Control forecast (IFS 9-km resolution)

DestinE (IFS 4.4km resolution)

AIFS-single (AIFSv1.0 ~0.25 resolution)

AIFS-ENS control forecast (~0.25 degree resolution)

3.3 Ensemble distribution

EFI (based on IFS 9-km ensemble)

The plots below show EFI for 24-hour precipitation valid on 10 September.

The plots below show EFI for 24-hour integrated water vapour flux valid on 10 September.

Forecast Evolution plot

The plot below shows the evolution for the 24-hour precipitation around Rejika on 10 September (see event defnition above).

3.4 Sub-seasonal forecasts

3.5 Comparison with other centres

4. Hazard Forecasts

5. Dedicated Experiments

6. Event Summary

6.1 Good and bad aspects of the forecasts for the event

• Relatively good signal in the medium-range EFI for precipitation due to the strong water-vapour flux
• The local forecast for Rejika not better in IFS and AIFS.

6.2 Experience from general performance/other cases

7. Additional material