Praia de Angeiras tornado, Matosinhos municipality, January 10 2016
2016-01-12 (IPMA)
By dawn of the 10th of January, on the Praia de Angeiras location in Lavra, Matosinhos municipality, there was a very strong wind episode with some destruction in homes, particularly noticed in unroofing, damage to windows and also in vehicles. The produced damages were seen to be consistent with tornado activity.
Mainland Portugal was, then, under the influence of a low system centered over the British Isles. The corresponding frontal disturbance was evolving over northern Iberia. Northern Portugal was still under the influence of a maritime tropical air mass, situated in the warm sector, by 3 UTC (3 am, local time). Over this area, several squall lines were propagating with a southwest-northeast general orientation, embedded in relatively stable air. By that time, it was also notorious a jet stream over the region, centered around 300 hPa (9000 m altitude).
Although the air mass was characterized by a relatively modest moisture content and low instability (in the synoptic scale), the said jet stream may have organized and forced stronger updrafts (in the local scales) by the mentioned squall lines area. Moreover, this could be confirmed by the presence of cloud tops over 6000 m altitude in the squall line that was propagating over Oporto city, as observed by the Arouca/Pico do Gralheiro (A/PG) radar station. The vertical wind profile that was retrieved from radar observations and rawinsonde data has shown just moderate wind shear values, both in the 0-6 km and 0-1 km layer. Despite these relatively low values, the radar observations also revealed the presence of several small spatial scale, relatively short lived, perturbations which still had features consistent with the diagnosis of supercell (SC). The same observations have allowed to follow a particular SC that propagated over the exact location of the reported damages, during the early hours of the 10th of January.
Figure 1 is an animated loop of the reflectivity field, showing the evolution of two squall lines, being visible several convective cells. The one that would reach the Praia de Angeiras location is highlighted in the squall line located further north. Figure 2 is an animated loop of the Doppler storm relative velocity. This field enables the identification of different rotation patterns and the one corresponding to the SC that would reach the said location is also highlighted.
This relatively organized convective form may have spawned a tornado over the sea that propagated inland or, alternatively, it may have spawned a tornado just over land, producing the reported damages. The SC has reached the Praia de Angeiras location by 2:21 UTC.
According to the damages, the tornado classification can be F0/T0 (3s gust, in the range 18-25 m/s) or, at best, F0/T1 (3s gust, in the range 25 -33 m/s). "F" means the classic Fujita scale and "T" means the TORRO scale (Tornado and Storm Research Organisation)
-
Lisboa:
UTC:
Copyright © Portuguese Institute for Sea and Atmosphere 2025
-
