A colder air mass coming from the Balkans is causing a decrease in temperatures in Italy (especially along the Adriatic coast). As shown in Figure1, the temperatures observed this late afternoon are below 10 °C in Northern and Central Italy (except in the coast of Liguria), with values below 0°C in the Alpine region. In the south, milder temperatures are observed especially in Sicily and southern Calabria (temperatures above 15°C).
Compared with yesterday afternoon (Figure1), a decrease in temperatures between 2-5°C has been observed in the Alps and Po valley, as well as in central Italy. However, this colder air (which will continue, especially in the north, throughout this week) is simply bringing the temperatures towards the average of the last week of November; thus, the real anomaly have been the very mild temperatures (especially the minimum) observed during the whole month (except for few ‘cold’ days: see Europe: First cold wave of the season ) in the Mediterranean region and the current month might become one of the warmest ever recorded in some areas.
Regarding the weather conditions (Figure2), clear skies have been dominant in the north, Sardinia and Tyrrenian coast. Typical of this weather condition is the stau effect, visible from the satellite imagery, from Marche to Puglia, caused by the easterly winds which blows above the Adriatic sea (picking up moisture) and, once raising on the Appennines barrier, contribute to form clouds and precipitation on the Adriatic coast, instead clear skies and milder temperatures are observed on the western side of the Appennines (i.e. Tuscany, Lazio, Campania).
Tomorrow clear skies will be mostly everywhere, with still some rainfall possible on the Adriatic coast (with snow on the Appennines above 1000-1500 m). On Friday overcast conditions will be in northern-central Italy (and later in the day also in the south) with showers expected from Friday morning on N.W. Italy (mainly on the Alps with snow above 500-800 m), in the afternoon between Umbria, Lazio and Tuscany and during the evening in south/western Sardinia.
The temperatures will decrease (especially on Friday), with minimum values below 0°C in the north (Alpine region and Po valley) and in the mainland in central Italy. The maximum temperatures will be below 10 °C in the north and Appennines (both tomorrow and Friday), between (10-12°C) along the Adriatic coast, (10-14°C) along the Tyrrenian coast and (14-16°C) in Sicily.
Thus, the colder air will simply cause a decrease in temperatures towards values closer to the normal conditions of this time of the year, breaking the anomaly lasted for several weeks with osberved temperatures close to 20 °C (as happened in central-southern Italy) and no cold nights (temperatures below 0°C) in the north.