The influence of a mesoscale convective system (MCS) in the evolution of two wildfires that started during the afternoon of 17 June 2017 in Pedrógão Grande, Central Portugal is discussed and analysed using weather radar data, weather stations, video images and fire spread analysis. As the MCS approached the region, its convectively driven flows started to influence the fires. The overturning flows were formed by two main limbs: one organised as front-to-rear deep layer inflows that propagated over the convective region of the MCS and the other as rear-to-front mid-level inflows that descended below the anvil structure of the MCS. The rear-to-front inflows, while accelerating and descending to lower levels, contributed to modify the fires’ intensity and plume characteristics. After the two fires merged, the resulting junction fire became very intense and impossible to control. Then, a firestorm was generated, causing the deaths of 66 people. The main goal of this study is to detail the influence of the MCS in the fire spread, thus contributing to the general knowledge of outstanding fire behaviour modifications due to the influence of atmospheric convective processes.

On 23/12/2009, windstorm Xola struck mainland Portugal, causing serious damage in a small area north of Lisbon (Oeste region) and in the south region, inflicting economic losses of over EUR 100 million. In both areas, several power towers, designed to withstand up to 46 m s⁻¹ winds, were destroyed. The causes of these two distinct damaging wind events were investigated. Xola was revealed to have a prominent cloud head and a split cold front structure. In the southern region, the damages were due to downburst winds, associated with a mesovortex, observed in a bow echo line triggered by an upper cold front. The cloud head presented several dry air intrusion signatures, co-located with tops progressively lowering towards the hooked tip. This tip revealed features consistent with the presence of slantwise convection, the descending branches of which may have been strengthened by evaporating cooling. At the reflectivity cloud head tip, a jet streak pattern was identified on weather radar, with Doppler velocities exceeding 55 m s⁻¹, just 400 m above ground. This signature is coherent with the presence of a Sting jet, and this phenomenon was associated with the strongest wind gusts (over 40 m s⁻¹) and the largest damages in the Oeste region.

From 2000 onwards, a systematic documentation of tornado reports was maintained at the Portuguese Meteorological Service (IPMA). The characteristics of 195 tornado events over land and at sea off the coast of mainland Portugal, Azores, and Madeira Islands, reported until 2020, were compiled into a new tornado database for Portugal. Each event was identified through the direct observation of the vortex, photography or video footage, or eyewitness descriptions, as well as by site surveys, including the interpretation of traces of the tornado found on the ground. For events after 2006, each data record was complemented with Doppler radar observations and derived products, which allowed a tornado type (TT) classification. The synoptic regimes and atmospheric environments favoring each type were identified using observations and numerical weather prediction model data. Results showed that tornadoes over Portugal were more frequent during autumn, winter, and spring. It was found that the occurrence of more than one tornado on the same day was frequent. The most intense tornadoes, classified as F3 intensity, were spawned by supercells, but a large proportion of weaker, shorter-lived, but still damaging tornadoes were found to be spawned in association with quasi linear convective systems (QLCS).