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In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. It is the opposite of a high-pressure area . Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible rain or storms), [ 1 ] while high-pressure areas are ...
A low-pressure area is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. [1] The formation process of a low-pressure area is known as cyclogenesis. [2]
The atmospheric pressure at the center of a recognizable high or low-pressure area at any given instant, i.e. the highest pressure in a high or the lowest pressure in a low. [2] ceraunometer An instrument used for counting the number of lightning discharges within a specific radius. [2] chinook wind
When meteorologists use the term: low pressure area, what are they referring to?
A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. Since low pressure implies a low height on a pressure surface, troughs and ridges refer to features in an identical sense as those on a topographic map. Troughs may be at the surface, or aloft, at ...
Isobaric analysis is performed on these maps, which involves the construction of lines of equal mean sea level pressure. The innermost closed lines indicate the positions of relative maxima and minima in the pressure field. The minima are called low-pressure areas while the maxima are called high-pressure areas.
Though the lowest pressure may be second to the Night of the big wind low, which saw a value of 27.25 inches of mercury (923 hPa) at Sumburgh Head, Shetland on non-calibrated, non-standard equipment 6–7 January 1839, with the mainland at Cape Wrath reporting an observed pressure of 27.32 inches of mercury (925 hPa).
A low-pressure area of calm, light variable winds near the equator is known as the doldrums, [8] near-equatorial trough, [9] intertropical front, or the Intertropical Convergence Zone. [10] When located within a monsoon region, this zone of low pressure and wind convergence is also known as the monsoon trough. [11]