The Mediterranean sea and the Black sea are both much warmer than is usual for this time of the year.
The Mediterranean sea is currently about 1-2 °C warmer than the 1982-2012 average. The warmest parts are in the northern Mediterranean off the coast of south France and northwest Italy and in the northern Adriatic sea. Both of these areas are 2-3.5 °C warmer than average. The Black sea is even more anomalously warm: much of it is 2-4 °C warmer than average for this period! The extreme northwestern part is up to 5 °C warmer than average.
Sea surface temperature anomaly (difference between current and average temperature) over the Mediterranean and Black seas on September 14. Map: our co-admin Andrej Flis.
Above average sea surface temperatures increase moisture content in the airmass over the sea, increasing convective instability and fueling thunderstorms. It also provides more precipitable water for late autumn flood setups along the coastal areas of the Mediterranean.