The Portuguese Institute for the Sea and the Atmosphere (IPMA) has modified the criteria for issuing thunderstorm weather warnings. The change aims to make warnings more representative of dangerous phenomena associated with storms and their potential impacts.
Previously, warnings were primarily based on the forecast of electrical discharges. Now, the assessment will also include other severe phenomena that can accompany thunderstorms, such as heavy rainfall, strong wind gusts, and hail. The new methodology jointly analyzes the spatial and temporal distribution of lightning and the characteristics of associated meteorological phenomena.
Warning levels are detailed: yellow indicates conditions favorable for localized phenomena, with rain up to 20 mm/h, hail under 2 cm, and gusts of 70-90 km/h. Orange warnings predict very heavy rain (20-40 mm/h), hail of 2 cm or more, and gusts over 90 km/h. Red alerts are reserved for extreme events with potential for significant impacts, including very heavy precipitation (over 40 mm/h) and large hail.
