201412 - Snowfall - Greece, Italy, Algeria

Status:Finalised Material from: Linus

Discussed in the following Daily reports:

Picture

1. Impact

On the last days of 2014 Greece, Italy and Algeria received a lot of snow. Even places like Sparta was hit and an observation in the area measured 20 cm. In parts of Italy the snow also caused problems.

2. Description of the event

The plots below shows the evolution of the atmosphere before the event and the development of the cut-off low.

z500 and t850 analysis

1. 25 Dec	2. 26 Dec	3. 27 Dec	4. 28 Dec

5. 29 Dec	6. 30 Dec	7. 31 Dec	8. 1 Jan

MSLP and precip "analysis"

1. 25 Dec	2. 26 Dec	3. 27 Dec	4. 28 Dec

5. 29 Dec	6. 30 Dec	7. 31 Dec	8. 1 Jan

3. Predictability

3.1 Data assimilation

The plot below shows the snow analyses from 31 December 06z and 1 January 06z.

3.2 HRES

3.3 ENS

The series of plots below shows EFI and SOT for snowfall on 30 December.

EFI 30 December

1. 30 Dec 00z	2. 29 Dec 00z	3. 28 dec 00z	4. 27 Dec 00z

5. 26 Dec 00z	6. 25 Dec 00z	7. 24 Dec 00z

The series of plots below shows EFI and SOT for snowfall on 31 December.

Already the longest forecasts (day 6-7) had a signal in SOT (contour lines) for extreme snowfall.

EFI 31 December

1. 31 Dec 00z	2. 30 Dec 00z	3. 29 Dec 00z	4. 28 Dec 00z

5. 27 Dec 00z	6. 26 Dec 00z	7. 25 Dec 00z

The plot below shows the CDF for snowfall for a point close to Tripoli (37.5N,22.4E).

3.4 Monthly forecasts

The plots below shows the temperature anomaly for 29 Dec - 4 Jan from the monthly forecast. There were a sign of the cold anomaly in the forecast from 22 Dec and the signal is strong from the 25th.