Status:Ongoing analysis Material from: Linus, Mohamed
Discussed in the following Daily reports:
http://intra.ecmwf.int/daily/d/dreport/2015/01/02/sc/
http://intra.ecmwf.int/daily/d/dreport/2015/01/06/sc/
http://intra.ecmwf.int/daily/d/dreport/2015/01/07/sc/
http://intra.ecmwf.int/daily/d/dreport/2015/01/08/sc/
http://intra.ecmwf.int/daily/d/dreport/2015/01/09/sc/
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On 9-10 January 3 severe storm hit north-western Europe. The first hit Scotland early on Friday 9 January with wind gusts up to (? mph) and later Denmark and Germany. The second one (named Nina in Norway) hit the Norwegian west coast on Saturday 10 January with hurricane force on 5stations ( http://artikkel.yr.no/sa-sint-var-nina-1.12143639) and a maximum mean wind of 37 m/s on Eigerøya. A third cyclone formed (named Egon in Sweden) in lee southern Norway and caused hurricane wind gusts in southern Sweden and heavy snowfall further north. The wind also led to elevated sea-levels along the Norwegian and Swedish coasts.
The evalution below is both for the Friday 9 January and Saturday 10 January.
The plots below show observed 24-hour maximum wind gusts for 9, 10 and 11 January. For the 9 January the worst affected areas were Scotland together with Denmark and Germany. On 10 January the strongest winds occurred along the Norwegian west coast. Sweden was also hit by strong wind gusts late on the 10th. On 111 January the strongest gusts were found around the Baltic sea.
The plots below show satellite images from yr.no every third hour. In the image sequence one can follow the development of the three cyclones.
The cyclones formed in connection to a strong baroclinic zone. The plots below shows the analyses of z500 and t850 every 12th hour.
The plot below show the jet steam and MSLP (in polar projection) for the same analyses as above.
The plots below show 12-hour forecasts of MSLP and precipitation.
The plots below show the 24-hour maximum wind gusts from HRES valid for 9 January.
The plots below show the 24-hour maximum wind gusts from HRES valid for 10 January.
The plots below show the cyclone feature plots for maximum wind speed at 1 km height inside a 600 km radius for 9 January 00z.
The plots below show the cyclone feature plots for maximum wind speed at 1 km height inside a 600 km radius for 10 January 12z.
The plots below show EFI and SOT for wind gusts valid 9 January.
The plots below show EFI and SOT for wind gusts valid 10 January.
The plots below shows probabilistic forecasts and verification of a binary event defined as exceeding 2-year return period for 24-hour maximum wind gusts.
First plot: 8 January 06z - 9 January 06z. Second plot: 9 January 06z - 10 January 06z.
The plot below shows a 2-d plot of projections into regime 1 (NAO+) and regime 2 (Scandinavian blocking), where each plot represents an analysis at 00z and the last point (lower right) the the 11 January. On 9-10 January the projection was very strong on positive NAO.
The plot below shows the ensemble forecast of projection to regime 1 where the x-axis represents the initial time of the forecast. Forecast from 1 January and onwards had a strong positive NAO signal, especially from the 4 January and onwards.
The plot below shows forecasts from different centres for probability for >25 m/s 10-metre mean wind from 6-hourly data, valid 10 January. The data are from the TIGGE archive.
The plots below are the same as above but for 10 January.