Exceptionally strong wind hit the coast between Cape Roca and Cape Carvoeiro on 17th October 2015: preliminary analysis
2015-10-21 (IPMA)
A low pressure system located in the Atlantic region to the East of the Azores islands, between mainland Portugal and the Madeira Islands, isolated from the west flux, has affected, alternately, the weather in Madeira and in Mainland since the October 15th.
On October 17th, the system approached the southwestern region of mainland Portugal, deepening and moving along the West Coast in South-North direction. The depression was centered 50 km to west of Cabo Carvoeiro at 1:00 pm, local time, with about 988 hPa pressure value (Figure 1).
During the trajectory, the weather conditions in mainland were affected very significantly, namely the atmospheric pressure, the wind speed and precipitation.
At the Automatic Weather Station of Lisboa/Gago Coutinho the pressure fell down 7 hPa between the 04 and the 11:00 am (Figure 2).
Gusts exceeding values 90 km/h occurred in various locations near the coast and in the highlands, with the higher values of mean wind speed and gust on the West Coast to the south of Cape Mondego, in particular between Cape Carvoeiro and Cape Roca. In this part of the coast, the values of average wind speed and gust were exceptionally high, requiring a careful analysis.
According to a provisional validation of the intensity of the wind, in the period between 08:00 am to 3:00 pm, local time, in that region, exceptionally high values of average wind have been reached, between 70 to 90 km/h, and gusts up to 140 km/h. Higher values of average wind and gust have been recorded at the IPMA’s weather station Cabo Roca, where the maximum gusts was 169 km/h in October 17th.
Heavy precipitation as recorded at various locations in the territory, especially in the Central region and in Alto Alentejo, where the hourly precipitation values were above 20 mm in some places, namely in Elvas (24 mm) and Proença-a-Nova (23 mm) in October 17th and in Coimbra (26 mm) in October 18th.
The accumulated precipitation in 24 hours, was also very high, Figure 3a and 3b. The highest values accumulated precipitation in 24 hours was recorded in Penhas Douradas, with 83 mm, and in Fundão, with 64 mm (between the 01:00 pm on 17th and 1:00 pm on 18th) and in Elvas, with 77 mm, between the 11:00 am on 17th and 05:00 pm on 18th.
In October 18th the low system moved to west and a significant decrease in the intensity of the wind has occurred, as well as an increase in atmospheric pressure values.
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Lisboa: 01h46mUTC:0h46m
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