Rain and thunderstorms may return to several regions of mainland Portugal on Saturday, September 5. The latest forecasts from the European ECMWF model, analyzed by Meteored, point to an increase in atmospheric instability, especially in the North and Center of the country. On Friday, September 4, dry weather should predominate, although some scattered showers may form in the late afternoon along the western coast.
The instability signal is more consistent in the regions of Minho, Trás-os-Montes, Douro and Beiras, as well as different mountainous areas of the North and Center. The Beira Interior and, occasionally, the Alentejo may also be affected during the afternoon. However, the precipitation will be very irregular and localized, with significant differences possibly existing between nearby localities.
Despite the rain, the heat will continue in the country's interior, with temperatures that could reach around 38°C in Castelo Branco and Portalegre and approach 39°C in Évora and Beja. This thermal contrast, together with the existing atmospheric conditions, favors the development of showers and thunderstorms during the hottest hours. Hail and strong wind gusts may also occur in some cells.
The window of greatest instability should be concentrated essentially during Saturday, particularly between late morning and the afternoon. For Sunday, September 6, the ECMWF projects a more stable scenario again, practically without precipitation. The forecast may still change, since this type of precipitation presents high spatial irregularity.
