Status: Finalised Material from: Linus, Ivan
1. Impact
The windstorm Ciara affected large part of north-western Europe on 9 and 10 February.
Storm Ciara affected the UK on Sunday, 9th Feb. The main hazards were strong gusty winds which uprooted trees, damaged buildings, and disrupted transport. Energy companies said that 675,000 homes lost power during the storm. An amber warning of strong winds was in force over much of England and Wales. Wales was hit by some of the strongest winds, with 93 mph (~ 150 km/h, 41 m/s) recorded in Aberdaron, north-west Wales. Manchester Airport also recorded gusts of 86mph (138 km/h, 38 m/s). Overall, the highest gusts were measured in Wales and much of England - widely between 25 and 32 m/s. Storm Ciara brought heavy rain in some places such as Cumbria, NW England and Wales. This rain was orographically enhanced and substantial totals were recorded in 24 hours: Honister Pass, in Cumbria received 177 mm and few other places in that area reported 24h totals close to 100 mm.
A report from UK Metoffice can be found here: https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2020/2020_02_storm_ciara.pdf
2. Description of the event
The plots below show 24-hour maximum wind gusts (m/s) and precipitation totals (mm) from 00 UTC on 9 Feb to 00 UTC on 10 Feb.
Satellite Air mass RGB for a 48-hour period starting from 12 UTC on 8 Feb every 15 min.
The plots below show ECMWF analyses of MSLP and 200-hPa wind between 00 UTC 8 Feb and 18 UTC on 10 Feb every 6 hours. Storm Ciara is labelled.
The plots below show analyses of MSLP and 6-hour precipitation forecasts every 12h hour between 7 and 11 February.
The plots below show analyses of z500 and t850 every 12h hour between 7 and 11 February.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show observations of 24-hour maximum wind gusts valid 9 February 00UTC to 10 February 00UTC (first plot) and HRES forecasts valid at the same period. The forecast plots also includes MSLP valid 9 February 12UTC (grey contours).
3.3 ENS
The plots below show EFI and SOT for wind gusts valid 9 February.
The plots below show the cyclone feature plots valid 9 Feburary 12UTC, with the colouring of the dot marking the maximum wind speed within 300 km.
The plot below shows the evolution of forecast for 24-hour maximum wind gusts valid 9 February 00UTC to 10 February 00UTC for Reading. The plot includes ensemble (blue box-and-whisker), HRES (red dot) and model climate (red box-and-whisker).
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
- Good early signal
- General overestimation of the wind gust over land (maybe also mean wind)