Status:Ongoing analysis Material from: Linus

Picture

1. Impact

Storm Frank hit Scotland on the 29 and 30th of December. The heavy rains associated with Frank that fell overnight 29th to the 30th December lead to new maximum peak river levels recorded on the Dee (Grampian).

https://floodforecastingservice.net/2016/02/19/storm-frank-how-was-the-medium-range-flood-guidance/comment-page-1/#comment-2258

2. Description of the event

The plots below show the MSLP (contour) and wind speed at 200 hPa in the analyses from 28 December to 31 December. A strong cyclone (Frank) formed over northern Atlantic on 29 December.

3. Predictability

3.1 Data assimilation

3.2 HRES

The first plot below shows the observed precipitation 29 December 06z to 30 December 06z and the following plots accumulated precipitation for the same window from HRES from different initial times. The forecast plots also include the MSLP valid for 29 December 18z.

3.3 ENS

The plots below show the EFI and SOT for precipitation on 30 December from different initial times.

3.4 Monthly forecasts

3.5 Comparison with other centres

4. Experience from general performance/other cases

• See 201512 - Rainfall - British Isles - Part 1 and 201512 - Rainfall - British Isles - Part 2

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

• Consistent EFI signal from 26 December and shifted somewhat further south on 25 December
• Underestimation of orographic precipitation?

6. Additional material