Hot and windy sunday!
Much of Europe, including the Pyrenees is under the spell of an intense heat wave at the moment. You’d think hot and sunny would imply great flying conditions, but the first day of the X-Pyr is always a bit special and this edition is no exception. Strong south winds will make flying conditions very difficult.
Synopsis:
An Atlantic low far out over the Azores is deepening and amplifying the ridge over western Europe, leading to an Omega-Pattern. This amplifying is connected with the advection of hot air from the subtropics and northern Africa, subsequently leading to an intense heat and a surge of increasing south wind over Spain.
At lower layers, the southerly winds get deflected along the Pyrenees, forming a “barrier-jet-like” south-easterly flow. With the decreasing mountain height of the Euskadi hills, the south-easterly winds get channeled over the Basque Country, are accelerated and spilling over from Spain into France, blocking the Sea breeze long into the afternoon.
Details:
With the effects of the south wind probably not yet established, the early morning can see some low clouds over Hondarribia, however they will disappear quickly. With intense insolation and the onset of weak south winds at the ground, temperatures will quickly increase and reach maximas around 38 to 40°C in the afternoon.
Thermals:
An inversion between 1000 and 2000 MASL will be present until around 12:00 LT, disappearing later on. The thermal top in the areas close the sea is expected around 1600 to 2200 MASL, with slightly higher topography, towards TP 2, theoretically even 3000 MASL are possible with a good looking gradient – however any thermal development will quite likely be very disorganised and ruptured by the wind.
Winds:
At 1000 MASL, windspeeds between 35 and 45 km/h are forecasted with the peak in between 10:00 and 12:00 LT. During the afternoon, the winds are decreasing slightly, but still remaining around 30-40km/h at 1500 MASL. The strong south wind is also present – and even stronger in the upper layers up to 4000 MASL, but these altitudes are probably out of reach on Sunday…
Outlook:
The south wind is weakening significantly towards Monday and only remain present with moderate strength in the vicintity of TP 1. The higher mountains see weak northerly winds and cloud base at 4000+ MASL and some overdevelopments with thunderstorms especially in the central and eastern Pyrenees. This pattern is persisting until mid-week. Towards the end of the week, the Atlantic trough is closing in slowly, quite possibly leading to increasing south-west winds and instability.
