WeatherBlog 15 2018/19 | Dorit is followed by Erika

Today, Wednesday, a shortwave trough between Erika and Dorit is grazing the Alps and clouding the seemingly eternal sunshine. Tomorrow, Thursday, this may still be felt a little in the eastern Alps, but High Erika is approaching from the west. Friday will be very sunny in the west, but a little less certain in the east: it's possible that the remaining disturbances here will manage to get in Erika's way for the time being and provide clouds and a few snowflakes. No significant changes at the weekend - sunny in the west, a little cloudier in the east, but the trend here is also clearly moving from "maybe a few clouds" to "sun as far as the crystal ball can see". Temperatures will remain mild for the time of year.

Synoptically a little more interesting than Dorit and Erika, the two blocking bum highs (meteorological term!), is the low upstream, i.e. to the west, of Erika. An advance of cold air in the area of Greenland will lead to rapid development of low pressure today and tomorrow. The resulting trough extends far to the south and pushes warm air towards Central Europe on its eastern flank, which in turn strengthens High Erika. The low is expected to meet the criteria for a so-called bombogenesis, a particularly "bomb-like" or rapid type of cyclones in which the core pressure of the low drops by 24mbar within 24 hours.

Otherwise: MeteoSwiss blogs about Dorit, Erika and the blooming "Krokussli" as well as the radiation balance of the snow cover and the DWD warns of skin cancer and snow blindness on the occasion of the sunshine and is happy about beautiful satellite images.

The idea that the air "absorbs" water vapor, similar to a sponge, is a simplification that does not really correspond to the facts. When and how many water particles evaporate or condense has nothing to do with the other components of the air and the saturation concentration is also not a "question of space". If "the air" were a sponge, much more moisture would "fit in" than is the case at 100% relative humidity. Saturation occurs when evaporation and condensation on a water surface are in balance, i.e. the same number of particles change from the liquid to the gaseous state as vice versa.

The steam plumes from the power plants in the picture hit the "inversion ceiling" and move horizontally "along the ceiling" thanks to a light wind instead of rising further and, like the smoke from the wood fires, remain trapped in the inversion. The latter is much more problematic for the air quality in the city than the power plant steam and regularly gives Fairbanks top spots in the ranking of cities with the worst air in the USA.