Material from: Linus, Ivan, ...
1. Overview
Storm Éowyn brought on 24 January extreme winds to Ireland and western parts of the UK. Wind gusts peaked at 51 m/s on the western Irish coast in Mace Head where mean wind of 38 m/s between 04:00 and 05:00 UTC and an hour earlier, a mean wind of 38 m/s was recorded (the station stopped reporting after 05UTC). Inland Connaught Airport has recoded a maximum wind gust of 43 m/s while other stations in Ireland reported 35 m/s.
2. Analyses and Observations
2.1 Event Definition
Wind gusts: 24-hour maximum wind gusts on 24 January for a 0.25x0.25 box around Mace Head, Ireland (53.3N, 9.9W).
2.2 Analyses
The plots below show analyses of MSLP and 6 hour rainfall from 22 January 00UTC to 25 January 00UTC, every 12th hour.
2.3 Observations
Water-vapour satellite images from Meteosat, every 3rd hour.
Sounding 24 January 00UTC from Valentia.
2.4 Climatological perspective
3. Forecasts
3.1 Data assimilation and observation usage
The plot below shows the assimilation of the Valentia radiosonde from 24 January 00UTC. Observation (black), first guess (blue) and analysis (red). This was the time when the dry intrusion was just reaching this point.
3.2 Single Forecasts for the event (see Section 2.1 for definition)
Observations and analysis for the event
Note that we currently have problems to decode the wind gust observations from Ireland. The maximum on Mace Head (black box) was 51 m/s, corresponding to grey in the colour range.
Control forecast (IFS 9km)
DestinE (AIFS 4.4km)
AIFS deterministic
Wind gusts not available for AIFS.
AIFS ensemble
Wind gusts not available for AIFS.
3.3 Ensemble distribution
EFI and SOT for 1-day wind gusts on 24 January
Forecast Evolution plot for the event (see Section 2.1)
While all forecasts had an ensemble mean above the model climate mean, the signal for the event strengthen gradually from 18 January and onwards. From 22 January 00UTC all members were above the model climate maximum (black triangle). The maximum observed was 51 m/s.
Legend:
Analysis - green dot
ENS CF - red dot
DestinE - dark-green dot
ENS distribution - blue
ENS m-climate - cyan05U
The plot below shows the 10-metre mean wind in the forecast from 23 January 00UTC (CF - red, PF - blue) and observations. Not that observations are missing between 05UTC and 15UTC on 24 February. The control forecast captured the peak of the wind speed very well. Some ensemble members clearly overestimated the maximum wind speed.
Cyclone feature plots
The plots below show cyclone feature plots for minimum surface pressure valid 24 January 00UTC from different initial times.
3.4 Sub-seasonal forecasts
The plots below show the weekly average ensemble mean of z500 valid 20-26 December. The forecast from 13 January gave some indications of the through over Eastern Atlantic.
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
- Good medium-range signal for the event
- Too strong mean wind and wind gusts in IFS?