The past few days have been characterized by significantly below-average temperatures and repeated wet episodes. After another critical night with regard to frost on Friday, the temperature level will rise significantly and we will come very close to the summer mark regionally at the turn of the month. Congestion sets in in the south, while it will be foehn in the north. There are also signs of another greeting from the desert at the start of the new week.
Strong Foehn
Over the course of Saturday, the foehn steadily increased, reaching far into the lowlands in the afternoon. For example, it also prevailed in Zurich and brought temperatures of around 21 degrees – more than in the actual Foehn valleys. It reached a temporary peak on Sunday night, with the strongest gusts of 110 km/h in Altenrhein, 103 km/h in Meiringen and 100 km/h in Altdorf. On Sunday morning, it was still reaching the lowlands in places. In the early morning, it was still blowing strongly to gale force, and after a temporary weaker phase, it reached gust peaks of 96 km/h in Altdorf and Meiringen. As the day progressed, however, it slowly subsided.
Fig. 1: Peak gusts on April 27, 2024; Source: MeteoNews, Ubimet
Fig. 2: Previous peak gusts on April 28, 2024; Source: MeteoNews, Ubimet
Strongest wind gusts (<900m, as of 08:00)
Lowland stations | Strongest wind gusts (in km/h) |
---|---|
Altenrhein | 110 |
Meiringen | 103 |
Altdorf | 100 |
Gersau | 95 |
Giswil | 90 |
Glarus | 86 |
Evionnaz | 85 |
Vaduz | 84 |
Oberägeri | 82 |
Aigle | 76 |
Le Bouveret | 76 |
Chur | 75 |
Bad Ragaz | 74 |
Sankt Gallen | 72 |
Meiringen | 72 |
Oron-la-ville | 69 |
Quinten | 68 |
Brienz-Hofstetten | 67 |
Visp | 67 |
Sion | 66 |
Strongest wind gusts (>900m, as of 08:00)
The mountain station | Strongest wind gusts (in km/h) |
---|---|
Titlis | 121 |
Jungfraujoch | 117 |
Brülisau-Leugangen | 114 |
Gütsch | 112 |
Glacier des Diablerets | 110 |
Wildspitz | 102 |
Piz Martegnas | 101 |
Moléson | 98 |
Les Attelas | 98 |
Engelberg | 95 |
Pilatus | 86 |
Gornergrat | 86 |
Säntis | 84 |
La Dôle | 82 |
Great St Bernard Pass | 79 |
Adelboden | 76 |
Binn | 76 |
Corvatsch | 75 |
Crap Masegn | 70 |
Grimsel | 70 |
Variable Thursday
Today, Thursday, will bring an increasingly friendly mix of sun and cloud in the central plateau. Along the foothills of the Alps and towards the east, local showers are on the way in the morning hours, on the northern edge around midday. The snow line will rise from 600 to 700 meters to around 900 meters. By the evening, the clouds will clear in all regions and in many cases the sky will be cloudless. With a light south-westerly to westerly wind, temperatures will rise to 10 to 12 degrees Celsius, with the last widespread double-digit maximums occurring almost ten days ago (April 16). In the south, it will even be 15 to 17 degrees today with a similar degree of cloudiness.
Fig. 1: Course of maximum temperatures between April 15 and 24; Source: MeteoNews
Last tricky night
The clear conditions at the beginning of the night are likely to be watched particularly closely by farmers. Without clouds, good radiation conditions will prevail, causing temperatures to drop rapidly. The situation will be particularly tricky in the eastern midlands this night, with light air frost likely in the cantons of Zurich, Schaffhausen, St. Gallen and Thurgau in particular. Towards the west, the clouds that will appear from around midnight onwards will make for slightly less chilly conditions. But not only air frost (at an altitude of 2 meters) is critical for the advanced vegetation, for example the shoots of the grapevine are 50 to 100 cm above the ground. Directly above the ground, the minima can typically be 3 to 5 degrees lower than at a height of 2 meters. Even if no air frost is forecast, there will be widespread ground frost.
Fig. 2: Expected minimum temperatures on Friday night at an altitude of 2 meters; Source: MeteoNews/Ubimet
After this cold start, Friday will also be cloudy and changeable. There will be a lot of clouds, especially from western Switzerland to the Bern region and north-western Switzerland, where it will be wet at times with flakes from 1200 to 1500 meters. However, the sun may make an appearance between the clouds, especially in the second half of the day. In central and eastern Switzerland, on the other hand, it will be dry and friendlier all day. The shift of the high-altitude wind to a southerly direction will result in a gradually building southerly foehn. Temperatures will reach 11 to 13 degrees in the west and 14 to 16 degrees in the east and in the foehn valleys.
The aforementioned foehn situation in the north will lead to a congested situation on the southern side of the Alps. Under mostly cloudy skies, it will be wet at least occasionally with flakes from 1200 to 1400 meters. Highs will reach around 12 degrees.
Mixed weekend
In the run-up to an Atlantic low pressure system, we will remain in a southerly current over the weekend. Moisture will accumulate on the southern side of the Alps, where it will be mostly cloudy and repeatedly wet. Depending on the model, between 20 and 60 mm will accumulate by Sunday evening, sometimes significantly more in the Leventina and Maggia valleys. At 12 to 14 degrees, it will be a little too cool for the time of year.
Fig. 3: Precipitation total from Friday to Sunday; Source: MeteoNews/Ubimet
Things look better on the northern side of the Alps. Particularly in the eastern half, you can expect a dry and fairly friendly to sunny weekend. Saturday will be the sunnier day than Sunday. Highs will rise to 18 to 20 degrees, with 22 degrees possible in the Alpine valleys with a strong southerly foehn at times. The western half will be closer to the low and the clouds will be more extensive. It will be at least occasionally wet, especially on Sunday night and Sunday, with the main focus likely to be on the Jura.
New Sahara dust at the start of the week
The weather at the start of the week will be less spectacular. It should continue to be sunnier in the east than in the west and south. However, the foehn will weaken noticeably. However, the air masses are still somewhat milder, at least in the east. On Monday and Tuesday, highs of between 22 and 24 degrees are possible, and in the foehn valleys a summer's day is also possible (25 degrees), while in the west it will probably be just under 20 degrees. The southerly flow at high altitude, which has now persisted for several days, will bring us back a recent visitor from the desert – the Sahara dust. On Monday and Tuesday , the concentration of Saharan dust should be high enough to at least be noticeable. It is not yet possible to estimate how the dust will affect the weather, but a high concentration of particles in the air generally promotes cloud formation.
Fig. 4: Sahara dust concentration on Monday evening according to SKIRON; Source: SKIRON
From the middle of next week, the next high-altitude low is likely to bring more unsettled and slightly cooler weather to the east. However, the exact timetable is still somewhat shaky at the moment and will gradually become firmer over the coming days. Up-to-date forecasts can be found on our website.
Fig. 5: Outlook until next Thursday; Source: MeteoNews
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