"Black Sea low" is a name used in Finland for those southern type of low pressures, whihc originate within the region northwest of the Black Sea. Typically these systems are responsible for the most intensive weather events in summertime, bringing great amounts of precipitation and thunder.
These lows have two main ways to originate:
- Type A: A low moves from the Mediterranean area towards NE, even filling a little in the beginning. However, it deepends again and turns towards N or NNE.
- Type B: A low developes within a stationary front which extends from South-east Europe towards north or north-west (on the eastern side of a major upper level trough over Central Europe). This stationary front marks a boundary separating very warm and moist continental air in the east from the cool airmass over the central parts of Europe.
The early wave stage of a Black Sea type B cyclone. The fully developed stage of a Black Sea type B cyclone. The images above illustrate the type B development, in which a minor wave within the baroclicic boundary starts to deepen and moves towards north-northeast. the development is often initiated by a small scale upper level trough appraoching from south or south-west and inducing cyclogenesis at lower levels. The Black Sea lows tend to slow down and become stationary over or near Finland (K. Frisk, personal communication).
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