Snowfall in the Northwest Iberian Peninsula: Synoptic Circulation Patterns and Their Influence on Snow Day Trends

Table 1

Average NAO index on heavy snow events, by cluster and station.

Cluster	1	2	3	4
Ávila	−0.30	−1.58	0.44	−0.79
Burgos	0.04	−0.12	0.06	−0.58
León	−0.22	−0.08	−0.50	−1.23
Palencia	N.A.	−0.72	N.A.	−0.65
Ponferrada	−0.82	−0.34	−0.97	−1.39
Salamanca	−0.06	−0.26	−0.09	−1.53
Segovia	−0.83	0.22	−0.37	−0.95
Soria	−0.17	−0.18	0.30	−0.80
Valladolid	N.A.	−0.28	−0.09	−1.70
Zamora	N.A.	−0.10	−0.75	N.A.
Total	−0.15	−0.05	−0.05	−0.88