Alps Weather Forecast - from St Moritz to Zugspitze 21st June 25

Summary - Fly fast to the North-East while watching the Thunders in the back!

Hi humidity, increased Cape and increased risk of precipitation will be established in the south Alps area which may have impact on the conditions from St Moritz to Zugspitze. 

The faster the pilots run away from it the better, as in the way to Zugspitze the possibility for rain will reach 80% expanding to the north from the south.

 

High clouds in the west will create shadow especially after 14.00h when the sun starts dropping in the west horizon, but this may be the good scenario as it will delay overdevelopment and precipitation eastwards. 

The barometer at around 1014mb, humidity 50%, dew point of 2,5 C. Temperature contrast 7C  (12-19C) assuming slow evolution of events, but enough thermal triggering over sunny areas.

Cloud bases are expected to be very high to the north (>4000m) with low Cu coverage, but thermals will not be usable higher than 3500m in the middle of the Alps at 14.00h. Especially to the southern regions of St Moritz, we expect some large Cu with tops above 6000m accelerating low valley winds, but the northern the better the conditions will be. The air pressure difference between North and South Alps may accelerate more the breeze flow inside the valley of St Moritz before the boundary layer starts working below the first inversion in the long valley.

Inversion levels at 1500 and 3150, but above higher ground the second inversion at 3500m.

Thermals 2,7m/s at 1500m, 3,5m/s at 1800m, +4m/s at 2000m, +5m/s from 2600 to 3300m.

Top of lift at 3500m.at 14.00h

Ideal thermal zone 2000-3500m

Average thermal 3.25m/s but above the first inversion of 1500m.

Sun energy 300W/m2

Winds

Gust 15

At all altitudes 10-15 kph NNW.

The day starts organizing thermals at 11.00h

Conditions start declining after 16.30h

Peak period 13.00h-15.30h

Peak time of conditions 14.00h

Duration 6h if not rain at 16.00

Potential XC speed 27kph

Potential flying distance 175km

Precipitation, 80% propability to the South part of the highway to Zugspitze   Good luck and keep safe

Evangelos