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The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked as a dashed line or bold line. In the UK, Hong Kong [1] and Fiji, [2] it is represented by a bold line extended from a low pressure center [3] or between two low pressure centers; [4] in Macau [5] and Australia, [6] it is a
[14] [15] High-pressure systems are alternatively referred to as anticyclones. On weather maps, high-pressure centers are associated with the letter H in English, [16] or A in Spanish, [17] because alta is the Spanish word for high, within the isobar with the highest pressure value. On constant pressure upper level charts, it is located within ...
A surface weather analysis for the United States on October 21, 2006. By that time, Tropical Storm Paul was active (Paul later became a hurricane). Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations.
Surface weather prognostic charts for mariners indicate the positions of high and low pressure areas, as well as frontal zones, up to five days into the future. Surface wind direction and speed is also forecast on this type of chart. Wave prognostic charts show the expected sea state at some future time. [2]
2013's Tropical Storm Dorian as a tropical wave just north of Puerto Rico on July 29, 2013. A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of ...
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]
A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure.It often forms behind an extratropical cyclone (to the west in the Northern Hemisphere, to the east in the Southern), at the leading edge of its cold air advection pattern—known as the cyclone's dry "conveyor belt" flow.
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]