The influence of land on precipitation
The climate diversity of Catalonia is remarkable, with significant variations that challenge popular sayings. One of the most well -known, ‘Gregal Mou and Llevant Plou’, does not always reflect the meteorological reality of the territory. Precipitation in an area depends on multiple factors, including air temperature at high heights, synoptic configuration and location of atmospheric action centers.
The crucial role of the mountains
In Catalonia, the presence of mountains is essential to determine the weather conditions. Mountain ranges such as the Pyrenees, the Montseny and the Prades Mountains act as barriers that influence the behavior of the winds. When the humid air of the sea is facing these elevations, it is forced to ascend, a phenomenon known as a lever effect, which causes the formation of clouds and, eventually, precipitation.
Identifying the favorable winds
To identify which winds are most beneficial to rain in each area, it is essential to observe their orientation and draw lines perpendicular to the mountains. This helps us predict where the most abundant rainfall will occur.
The effects of the Levant and the gregal
The Levant is one of the winds that generates the most rain, especially in the counties of Girona and in the southern part of Tarragona. In this case, the sea wind reaches little resistance to the mountain ranges, allowing the conditions to be optimal for the formation of clouds. For example, the mountains that exceed 1,500 meters in Girona act as powerful rain generators.
Variations between Regions
Between the Girona and the southern region, mountainous orientations vary, affecting the nature of the winds. Whereas in the north the winds are most of the east, in the south there is an influence of the Xaloc, which can increase rainfall in areas such as La Selva and Baix Camp.
Gregal: a double personality wind
The gregal, which comes from the northeast, is not usually an ally of abundant rains in Catalonia. However, when this wind travels a great distance over the water, it can wear unexpected rains. In Barcelona, for example, this wind is known for its intensity and can cause sea storms.
Examples of extensive rains
One of the most important cases of rainfall related to Gregal is the Olive Register, in Valencia, where more than 800 liters were recorded in 24 hours in 1987, an example that illustrates how the interaction between the terrain and the winds can be extremely intense weather phenomena.
Other orographic factors
Orographic levers are not only found on the coast; The southern slope of the Pyrenees, for example, acts as another great rain generator. The mountains influence the direction and intensity of the winds, thus affecting the rainfall we experience.
Nature finally decides how and where the rains will occur, but the combination of winds and mountain formations offers valuable evidence of possible weather conditions in Catalonia.