Cerberus heatwave. Satellite image of land surface temperatures across Mediterranean and Black Sea bordering countries in the morning of 17th July 2023. Land surface temperatures are significantly hotter than air temperatures, which are used for weather forecasts. The heatwave was caused by an area of high pressure, or anticyclone, that moved northwards from the Sahara Desert. The high temperatures started on the 10th July. Data obtained by the radiometer instrument on the Copernicus Sentinel-3 satellite.