<P> Thermal lows form due to localized heating caused by greater sunshine over deserts and other land masses . Since localized areas of warm air are less dense than their surroundings , this warmer air rises , which lowers atmospheric pressure near that portion of the Earth 's surface . Large - scale thermal lows over continents help drive monsoon circulations . Low - pressure areas can also form due to organized thunderstorm activity over warm water . When this occurs over the tropics in concert with the Intertropical Convergence Zone , it is known as a monsoon trough . Monsoon troughs reach their northerly extent in August and their southerly extent in February . When a convective low acquires a well - hot circulation in the tropics it is termed a tropical cyclone . Tropical cyclones can form during any month of the year globally , but can occur in either the northern or southern hemisphere during November . </P>
<P> Thermal lows form due to localized heating caused by greater sunshine over deserts and other land masses . Since localized areas of warm air are less dense than their surroundings , this warmer air rises , which lowers atmospheric pressure near that portion of the Earth 's surface . Large - scale thermal lows over continents help drive monsoon circulations . Low - pressure areas can also form due to organized thunderstorm activity over warm water . When this occurs over the tropics in concert with the Intertropical Convergence Zone , it is known as a monsoon trough . Monsoon troughs reach their northerly extent in August and their southerly extent in February . When a convective low acquires a well - hot circulation in the tropics it is termed a tropical cyclone . Tropical cyclones can form during any month of the year globally , but can occur in either the northern or southern hemisphere during November . </P>
which type of air pressure is associated with warm air rising
which type of air pressure is associated with warm air rising
Low - pressure
Low - pressure