In just three weeks, we have experienced several warm episodes , and more importantly, some experts are already predicting the arrival of the first heat wave of the year. However, these anticipated temperatures are not the only heat that interests meteorologists. There are compelling reasons behind this increased focus.
A Very Warm Mediterranean
The Mediterranean Sea is reaching temperatures unseen in at least four years, significantly higher than what would typically be expected at this time of the year. The data provided by the SOCIB (Coastal Observation and Prediction System of the Balearic Islands) indicates that the water temperature is not only above the average recorded during this period from 1982 to 2015, but it also surpasses the 90th percentile of observations from recent years.
Heat Anomalies Across Different Regions
According to SOCIB data compiled on June 12, the average surface sea temperature presents an anomaly of 2.26º Celsius above the average expected during this time. This situation is particularly notable in the western Mediterranean , where thermal anomalies reach 2.65º . In the vicinity of the Balearic Islands , the sea surface is, on average, 3º above the norm, with waters in the Cabrera Archipelago National Park recording an anomaly of 3.18º .
Although the eastern Mediterranean displays a smaller thermal anomaly in absolute terms ( 1.9º ), it also surpasses the 90th percentile of data compiled during this period from 1982 to 2015. A similar trend appears in the Alboran Sea , one of the few regions in the western Mediterranean with a lesser increase of 2º (1.64º) but still above the 90th percentile.
What Is Happening?
According to meteorologist Duncan Wingen , as explained in Meteored, three key factors have contributed to this situation. Firstly, the absence of tramontana winds , which act as a “natural refrigerator” that cools the sea by facilitating the evaporation of surface water and the upwelling of colder, deeper waters.
Secondly, the stability created by subtropical anticyclones has pulled warm air masses and resulted in clear skies. Lastly, it is important to consider the thermal baseline. Data from SOCIB indicates that for the past several years, sea surface temperatures in the Mediterranean have remained nearly consistently above average. The last time temperatures dropped below this average was in April 2022 .
Future Forecasts
The situation is expected to change, but not for the better. According to models from the European Centre for Medium-Range Weather Forecasts (ECMWF) , by next Wednesday, a part of the central Mediterranean near the coast of Naples could exhibit thermal anomalies between 4.5º and 5º . A significant portion of the central Mediterranean and Alboran Sea may show anomalies exceeding 3.5º .
The forecast worsens further as we approach Monday, June 23 : ECMWF models estimate that large areas of the western Mediterranean might present thermal anomalies between 5º and 5.5º . By that weekend, most of the thermal anomaly could shift toward the east.
This could mark a moment when normal conditions return to parts of the western Mediterranean, potentially featuring a slight cold anomaly along coastal areas. It is important to highlight that these are medium-term forecasts; hence, uncertainties should be taken into account.
Why Is the Mediterranean So Important?
The question of why meteorologists focus so intensely on high sea temperatures relates to the fact that these temperatures affect conditions on land. High sea temperatures cause warm, humid air to rise into the atmosphere.
This scenario promotes the development of storms with increased destructive potential. The best example of this phenomenon can be found with hurricanes , but the Mediterranean also has its share of examples beyond the emergence of hypothetical medicanes or Mediterranean hurricanes. Cases such as DANA (Depresión Aislada en Niveles Altos) or the “cold drop” illustrate the virulent storms that can occur in the Mediterranean basin.
As we analyze these climatic developments, it becomes evident that understanding sea surface temperatures is vital for predicting and managing the environmental changes that can directly impact human safety and ecological systems.