WeatherBlog 24 2025/26 | April April does what it wants!

CURRENT SITUATION

The volatility announced last week has delivered. A dripping trough over Italy caused some exciting meteorological situations. In the eastern Alps, the precipitation was partly linked to a slightly westward moving warm front, while in the western Alps orographic lifting played the main role. Yesterday there were still lots of clouds and isolated showers, but today the situation is slowly beginning to calm down, with a weak high-pressure influence from the west gradually clearing the air. But it won't be completely clear. With the radiation, spring clouds will form again during the course of the day - April will remain true to itself.

OUTLOOK

The Alps will initially remain under the influence of high pressure until the weekend. From Thursday, the high-altitude current will become increasingly zonal, i.e. more of a westerly drift, bringing milder air to the Alpine region. In the northern Alps, it will be sunny and spring-like mild. In the Southern Alps, residual moisture will still be lingering around, resulting in longer periods of clouds and the potential for final precipitation. The air will continue to dry out overall, but the sun will now have enough power to cause new clouds to form every day. This means friendly mornings, cloudier afternoons and a chance of local showers. Towards Sunday, a cold front from the northwest will bring a little more dynamism. It remains to be seen whether Lord Ullr still has enough strength to strike back.

We now have a global model, ICON with a 13 km grid width, which provides us with the long-term forecast for 7 and a half days, and a high-resolution regional model, WRF-HRRR-AK with a 3 km grid width, which promises us the most accurate forecast for the next 48 hours. And perhaps we will soon be able to find these new PowderGrams on the map. They are both basically similar to the known PowderGrams, but focus more on radiation, clouds, visibility and temperatures: in particular, we have also realized the wind chill temperature.

The big differences between model orography and real orography are a particular challenge. The summit of Denali is 6190 meters above sea level, but even in a model with a grid width of 3 km it is only represented at an altitude of 3980 meters and in ICON only at 2650 meters. Consequently, a difficult vertical extrapolation must be carried out here with regard to temperatures and humidity, or one does without it and refers to the fact that this is model altitude and not real altitude.

The interpretation of the available data is the art of the meteorologist. While the sun is shining in Alaska today, we see little prospect of blue skies for the next 6 days, with the possible exception of April 18. So, dear Alaska, enjoy today and stay cheerful when it gets gray and uncomfortable. We will also provide PowderGrams for ski mountaineering in the Andes in May.

End of season WeatherBlog

Due to the advanced season and new challenges, we are announcing the end of the WeatherBlog season, unless special circumstances force us to write. We (Lea, Michael and Sebastian) appreciate the attention and are almost looking forward to the next WeatherBlog in winter 2026/27.