A slow start followed by great flying conditions – spiced with some overdevelopment.
With the persisting heat wave and weakening south wind, generally good flying conditions with a very high cloudbase can be expected. However stubborn morning stability and overdevelopments with thunderstorms around Añeto will quite likely limit the flying window.
Synopsis:
A ridge with very warm subtropic air is dominating the weather. With it’s axis directly over the western Pyrenees, the Iberian Peninsula und the most northwestern parts of the Pyrenees sees persisting south winds while the higher mountains from TP 2 eastwards are under a light to moderate northerly flow.
Details:
Hot temperature and strong insolation remain present until the late afternoon. Temperatures at low altitudes are again in the 35-40°C range, 0°C-isotherme is around 4500 MASL.
Thermals:
As a result of the heat present, during the night an isothermic layer below 2000 MASL forms, which is dampening thermal development in the forenoon. Mountains above 2000 MASL are much more promising for thermals before noon. It will probably take until 12-13:00 LT until a continuous good gradient is established in the layers below 2000 MASL, but once it is there thermals with a top of up to 5000 MASL (!!!) are expected. The best climbing rates remain however in the layers above 2000 MASL.
Around the Area of TP 4 Añeto, the models show some overdevelopments and thunderstorms towards the evening. The areas more to the west (towards TP 3) are less affected by overdevelopments. Also the French parts are most likely less affected. Because of the dry boundary layer, it is possible that the models are overestimating the risk for thunderstorms, however if they materialise, the risk for strong gusts in their vicinity is very real.
Wind:
While the lower mountains west of TP 2 remain in the influence of moderate southerly winds, the high mountains of the Central Pyrenees see only weak winds (5-15 km/h at 3000-4000 MASL). Valley wind systems can become moderate to strong and as mentioned there are strong to severe gusts possible around thunderstorms.
Outlook:
The general pattern remains similar on Tuesday and Wednesday. Slightly decreasing geopotential heigth at upper levels and slightly more humid boundary layer lead probably to earlier thermals than on Monday, but increasing thunderstorm-activity towards the evening.
