Just a couple of days ago, weather models began to glimpse the possible formation of a new isolated depression in height, known as a Dana , over Atlantic waters. Recent observations are confirming this expectation, leading experts to warn about the arrival of an intense weather phenomenon .
Special notice. The State Meteorology Agency (Aemet) has issued a special notice for storms and intense rainfall associated with the newly formed Dana. This weather situation will significantly impact the northern half and third of the Iberian Peninsula between tomorrow, July 11, and Saturday, July 12.
What’s happening. At the beginning of this week, meteorologists confirmed that the Peninsula was divided between two distinct air masses: one to the north influenced by vaguadas (troughs) and cold air, and another to the south characterized by anticyclonic patterns with persistent heat. While many hoped for a return to stability and heat, this turned out to be a mirage for parts of the country.
The cause of this deviation is the emergence of a Dana, an area of low atmospheric pressure that separates from the cold northern circulation. This Dana is forming to the west of the Iberian Peninsula and will soon be influenced by prevailing atmospheric circulation.
<img alt="The heat of the last weeks has been so extreme that we have already exceeded tropical nights: the equatorial nights are here" width="375" height="142" src="https://i.blogs.es/5a0a9a/corte-noches-ecuatoriales-jun25/375_142.jpeg"/>What we can expect. Aemet’s special notice forecasts the arrival of “high adversity storms” affecting the northern and third parts of the territory, which may be accompanied by large hailstones , strong winds, and torrential rain.
On Friday, July 11, the agency anticipates storms that will intensify in the Cantabrian mountain range and the Iberian system from the afternoon onward. These storms are expected to shift north or northeast gradually, potentially leading to hailstones exceeding 2 cm in diameter and rainfall accumulation of 30-40 mm within an hour , alongside “very strong” wind gusts.
On Saturday, July 12, Aemet predicts that the Dana will move eastward, bringing instability particularly to the western Peninsula and the northeast quadrant.
Uncertainty. The forecasts indicate a high probability of extreme weather associated with the Dana, but Aemet acknowledges a degree of uncertainty. They suggest that the likelihood of experiencing storms and intense rainfall is “very high,” estimated at over 70% , but it is not assured. They clarify that while this scenario is likely, the inherent uncertainty in such disturbances complicates the ability to specify precisely which areas will experience significant impacts.
As forecasts move further into the future, uncertainty increases. However, the agency estimates that the effects of the Dana may diminish by Sunday, July 13.
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Image | ECMWF