Why does Strong thunderstorms with heavy rain are forecast for this Monday evening and the night into Tuesday, with gusts of wind and hail also possible in some areas. Background information on the expect weather situation can be found in the
blog post
to find always updat warnings as usual in the MeteoSwiss app or on the
MeteoSwiss website
.
Precipitation is certainly not uncommon in the summer of 2024. Precipitation has been frequent since the beginning of summer. In June, the rainfall totals over the whole month were not exceptionally high on average in Switzerland (in some regions they were even in deficit), but the fact that it rain frequently (and especially on weekends) leaves a lasting impression.
Figure 2: Lightning strike in the Locarno region seen from
Figure 2: Lightning strike in the Locarno region seen from Brione on July 12, 2024. (Source: Meteomeldung / App MeteoSchweiz)
How can these frequent rainfalls be explain?
The map in Figure 3 shows the deviation of the pressure (more precisely: the height of the geopotential at 500 hPa) of this year’s June compar to the long-term average (reference period: June months of the years 1991-2020). This year, the Azores high was generally further northwest than average and the air pressure over Eastern Europe, Russia, Greece and Turkey was also higher than the norm.
Between these two high pressure areas, the low pressure areas afghanistan mobile database coming from the North Atlantic were forc to move towards Western Europe. As a result, lower pressure prevail over Great Britain, France and also over the Iberian Peninsula.
As a result of this constellation, Switzerland was often
A humid southwesterly flow This situation has chang little so far in July
Figure 3. Geopotential anomaly (in decameters) from 1 to 30 June 2024 compar to the average of the months June 1991-2020.
Figure 3. Geopotential anomaly (in decameters) expanding applications beyond images from June 1 to 30, 2024 compar to the average of June 1991-2020. (Source: NCEP–NOAA; https://psl.noaa.gov/data/histdata/)
Extremely changeable and often wet weather has also l to betting email list a deficit in the duration of sunshine. The average temperature, however, has remain within the norm. While the first half of summer (July 1 to July 14) can thus be declar rainy and sunny, it cannot be describ as cool (if one refers to the 1991-2020 average).
Precipitation has been frequent not only since early summer, but since last autumn. Figure 4 shows the pressure anomaly from October 1, 2023 to July 12, 2024. On average over this entire period, pressure from the British Isles to Scandinavia was lower than the 1991-2020 norm, while it was higher over the entire Miterranean region. This strengthen the prevailing westerly flow over Switzerland, with the result that disturbances from the Atlantic frequently mov over our country.