The latest updates from the European ECMWF model show a different scenario from the one initially predicted for the coming weeks in Portugal. Instead of a clearly dominant atmospheric pattern, the model now points to a strong alternation between three regimes: Atlantic Ridge, positive NAO (NAO+) and blocking. This change in forecasts significantly increases uncertainty regarding the evolution of weather conditions in the country.
The probability of the polar jet stream shifting northward has been increasing, which is related to the more frequent occurrence of patterns such as NAO+. Each of these regimes influences the atmospheric circulation over the North Atlantic differently, which could result in relevant changes in weather conditions in Portugal.
The current scenario contrasts with previous forecasts, which pointed to a more stable pattern. During NAO+ phases, the westerly circulation intensifies, which drives atmospheric depressions toward Europe. This alternation between different atmospheric patterns could mean significant variability in the weather in the coming days.
