1/5 During January of 2021 a western based negative #NAO (Fig. 1) was established leading to robust anomalies in #precipitation and #temperature over the N. Atlantic and #Europe according to preliminary analysis of @ECMWF #ERA5 data.

2/5 Most notably ones are the large precipitation anomalies across the western #Balkans and #Italy as it is usually the case during a persistent negative NAO phase. The persistent negative NAO was associated with an anomalous equatorward shifted upper-level jet stream (Fig. 2)

3/5 that was steering multiple extratropical cyclones from the Atlantic and #Mediterranean almost along the same storm track. This persistent storm track resulted in large positive anomalies of precipitation across western Italy and Balkan states (Fig. 3).

4/5 This large scale pattern was also associated with above average temperature anomalies across the SE Europe and below average temperature anomalies across the western Europe (Fig. 4).

5/5 Across NW #Greece many automatic weather station of the National Observatory of Athens ( @EAA_NOA)/ @meteogr recorded record-breaking monthly precipitation totals with the most exceptional one in Theodoriana, Arta with 915 mm of rain.