Synopsis:
The Atlantic Pyrenees are still in the area where the weather is affected by high pressure over the Atlantic and a low pressure system over southwestern France and the Mediterranean. In this area, the wind is usually from the northwest or north, bringing in rather moist air from the Bay of Biscay into the Basque Country.
Basque Country:
As the pressure rises, the humidity drops below 2000m, creating a thick low-level cloud cover over the Basque Country. The base of this cloud seems to vary in altitude, from 700 to 1200m. The humidity can rise along the mountains, causing drizzle, and local showers can also form along the coastline, especially in the afternoon.
To sum up the day, it was pretty humid at the lowest 2000 m, as shown in the vertical profile of ECMWF data for a point just southwest of TP1 Larun, by windy.com.
With the northerly wind direction, some lee effects are possible in the Spanish Basque country, leading to a locally elevated cloud base. However, the cloud cover remains thick there as well, and some potential downslope winds could make things a bit more complicated. The airmass would potentially be a bit drier in the Spanish mountains around Pamplona, but first you have to get there – and once there, the northerly winds remain an issue.
To sum up, Sunday is going to be a bit of a challenge, with only a few flights likely to take off. And the Basque fern will be making an appearance as well.
Outlook:
It looks like Monday and Tuesday will be much better for flying, as the air is drying up, even on the French side of the Pyrenees. With the winds calming down, these days should provide decent flying conditions.
Towards Wednesday and further on, there are still some uncertainties in the forecast.
