matalapaine

Matalapaine is a meteorological term used in Finnish to describe a region of relatively low atmospheric pressure, typically associated with a low-pressure system or cyclone. Central pressure is lower than the surrounding environment; scientists measure with barometers and report in hPa. In general, a lower central pressure indicates a potentially more vigorous system.

Formation and structure: Low-pressure systems form when air near the surface converges and is forced upward, or when cooler air aloft over warmer air creates instability. Rising air reduces surface pressure as air diverges at altitude. The system often features fronts, with a warm front and a cold front encircling the center. In the Northern Hemisphere, winds circulate counterclockwise around a low; in the Southern Hemisphere, clockwise.

Weather and impacts: Matalapaine systems bring cloud cover, rain or snow, and variable winds. They can cause stormy weather in coastal regions and disturb travel. The severity depends on the system’s depth, moisture, and interaction with topography.

Context and terminology: The opposite term is korkeapaine (high pressure). In weather forecasting, "low pressure" is a central concept for mid-latitude cyclones and tropical systems; Finland and Nordic countries are often influenced by Atlantic low-pressure systems moving eastward.