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Storm Desmond, the fourth named storm of the season, caused severe flooding, travel disruption and a power outage across northern England and parts of Scotland on 5 December. Flooding and travel disruptions were reported from Ireland as well. Cumbria in NW England is one of the worst affected regions with more than 200 mm of rain in 24 hours recorded in that area. Storm Desmond broke the United Kingdom's 24-hour rainfall record, with 341.4 mm of rain falling in Honister Pass, Cumbria. On Saturday, 5 December, UK Met office issued a red warning of heavy rain for Cumbria. The cyclone also led to flooding in southern Norway.
https://en.wikipedia.org/wiki/Storm_Desmond
2. Description of the event
The plot below shows the accumulated rainfall between 1 to 10 December.
3. Predictability
3.1 Data assimilation
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The EFI values were above 90% more than 3 days in advance. High values of the EFI and SOT show pretty well the potential of extreme rainfall in the affected areas. For the ENS the extreme rainfall values were lower compared to HRES.
3.4 Monthly forecasts
Verification of the monthly forecast valid the week 30 November - 6 December. The forecast from two weeks before the event had a wet signal for the northern British Isles and southern Norway.
The early signal was connected to the prediction of a postive NAO phase, as seen in the MSLP anomalies below.
3.5 Comparison with other centres
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