20 °C at 850 hPa – previously a rare occurrence
The evaluations of the radio soundings in Payerne have been available digitally since 1954. This results in a series of measurements spanning around 70 years. During this period, 20 °C and more were record on a total of 251 days, which amounts to around 3.6 days per year. Between 1954 and 1980, it was only around 1.4 days per year. Since the 1980s, 20 °C at 850 hPa has been record more and more frequently, and in the last 10 years, i.e. between 2014 and 2023, 20 °C and more were record on average on 8.4 days at 850 hPa.
There were also summers in which 20 °C at 850 hPa was never reach, such as in 1954, 1955, 1960, 1961, 1963, 1969, 1970, 1976, 1978, 1979, 1982, 1990, 1996, 1997 and 2008. From this it can be duc that in the 50s, 60s and 70s of the last century 20 °C at 1600 metres was never reach in one in three summers. However, recently, i.e. since 2008, this has no longer happen.
Number of days with a temperature above a certain threshold in the years 1954-2023
Number of days with a temperature above a certain threshold in the years 1954-2023. (MeteoSwiss)
At 850 hPa, 26 °C has already been record
Higher thresholds than 20 °C are trivially exce peru mobile database less often in the free atmosphere at about 1600 meters. A temperature of 23 °C or more was already record ten times less often between 1954 and 2023, namely only on 25 days. 25 °C and more only occurr five times, namely once each in 1984 and 2019 and three times in 1983, when an extreme heat wave prevail at the end of July. The previous high of 25.9 °C dates back to July 31, 1983.
The 20 hottest days over Payerne at 850 hPa (approx. 1600 m above sea level) in the years 1954-2023.
The 20 hottest days over Payerne at 850 hPa (approx. 1600 m above sea level) in the years 1954-2023. (MeteoSwiss)
Weather situation with very high temperature at 850 hPa over Payerne.
Average geopotential [gpm] and average temperature
[K] in Europe on the 20 hottest days at 850 hPa over Payerne in everything you ne to know about the dicat server the years according to the reanalysis tool 6-Hourly NCEP/NCAR Reanalysis Data Composites on the website https://psl.noaa.gov/data/composites/hour/. 273 K corresponds to 0°C, over Payerne the average temperature was just over 295 K, which agb directory corresponds to 22 °C. The actual value was over 24 degrees, so the reanalysis shows temperatures that are about 2 degrees too low. This is because the reanalysis can no longer accurately reconstruct the temperature and pressure fields at that time.
Average geopotential [gpm] and average temperature [K] in Europe on the 20 hottest days at 850 hPa over Payerne in the years according to the reanalysis tool 6-Hourly NCEP/NCAR Reanalysis Data Composites on the website https://psl.noaa.gov/data/composites/hour/. 273 K corresponds to 0°C, over Payerne the average temperature was just over 295 K, which