Material from: Linus, David, ..

1. Overview

On 20 January the  storm Harry impacted the southern-central Mediterranean with extreme rainfall and waves.

https://www.linkedin.com/pulse/cyclone-harry-southern-italy-between-extreme-disyf/

2. Analyses and Observations

2.1 Event Definition

Here we will focus on 24-hour maximum significant wave height on 20 January in a 0.5x0.5 degree box south-east of Sicily (centred on 36.2N, 15.3E).

We will also evaluate the 24-hour precipitation on 20 January in a box on Sicily (37.5N, 15E)

2.2 Analyses

The plots below show analyses of MSLP and 6 hour rainfall from 18 January 00UTC to 22 January 00UTC, every 12th hour

The plots below show analyses of z500 and T850 from 14 January to 23 January, every 24 hour.

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)

Analysis for the event

Control forecast (IFS 9-km resolution)

DestinE (IFS 4.4km resolution)

AIFS-single (AIFSv2.0 ~0.25 resolution)

AIFS-CRPS ensemble (~0.25 degree resolution)

3.3 Ensemble distribution

EFI (based on IFS 9-km ensemble)

The plots below show the EFI for 24-hour maximum significant wave height valid 20 January.

The plots below show the EFI for 24-hour precipitation valid 20 January.

Forecast Evolution plot

The evolution plot below shows the forecasts for maximum significant wave height on 20 January inside the box south-east of Sicily. For AIFS version 2 (orange) is used as that version is the first with wave forecasts.

The evolution plot below shows the forecasts for precipitation on 20 January inside the box on Sicily outlined in the observation plot below.

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

6.2 Experience from general performance/other cases

7. Additional material