...
An illustration of the evolution of the atmospheric flow and the forecast trajectories in the NAO-BLO space is given in Fig.3. The forecast trajectories from day 0 to day 10 of the ENS initiated on 23 February 2018 indicate a clear transition from a Scandinavian Blocking into a NAO- by day 5. Verifying analysis (black line) and the ensemble mean trajectories (red line) match quite closely and the evolution of forecast uncertainties (rather low in this case) is well depicted by the NAO-BLO phase space. Indeed, in late February early March, a spell of severe low temperatures with significant snowfall was associated with the establishment of a large pressure system over Scandinavia and later a development into a NAO- circulation.
...
...
...
...
PDFs and verification for the forecast issued about 4 weeks earlier. Daily verifying analysis is represented by yellow (first day of the target period) to brown (last day of the target period) circles.
...
...
...
...