pressure system pressure system relative peak sea level pressure distribution surface pressure sea level varies lowest value measured inhg highest recorded inhg low pressure systems evolve interactions temperature atmosphere temperature differences atmosphere water oceans lakes influence upper level disturbances solar heating cooling area receives pressure systems cause weather experienced locally low pressure systems associated clouds precipitation minimize temperature changes day high pressure systems normally associated dry weather clear skies larger temperature changes greater radiation night greater sunshine day pressure systems analyzed field surface weather maps low pressure system low pressure area low region atmospheric pressure sea level surrounding locations low pressure systems form areas wind divergence occur upper levels formation process low pressure area known cyclogenesis field atmospheric dynamics areas wind divergence aloft occur areas east upper form half wave trough large extends ahead embedded smaller winds aloft ahead cause atmospheric lift surface pressures upward motion partially force gravity thermal lows form localized heating caused greater sunshine land masses localized areas warm air dense surroundings warmer air rises atmospheric pressure near portion earth surface large scale thermal lows continents help create pressure drive monsoon low pressure areas form organized thunderstorm activity warm water occurrence occurs tropics concert known monsoon trough monsoon reach northerly extent august southerly extent february convective low defined circulation tropics termed tropical cyclone tropical cyclones form month year globally occur northern hemisphere southern hemisphere november atmospheric lift caused low level wind convergence surface low brings clouds potentially precipitation low pressure area cloudy skies act minimize temperature extremes clouds reflect sunlight incoming solar radiation causes lower temperatures day night effect clouds outgoing radiation heat energy surface allows warmer low temperatures seasons stronger area low pressure stronger winds experienced vicinity world low pressure systems frequently located lee rocky_mountains europe particular united_kingdom recurring low pressure weather systems typically known depressions lowest recorded non barometric pressure inhg occurred typhoon tip october high pressure system high pressure systems frequently associated light winds surface lower portion general dry air mass heating high pressure typically brings clear skies day clouds present reflect sunlight incoming solar radiation temperatures rise night absence clouds means outgoing radiation heat energy surface absorbed giving cooler low temperatures seasons surface winds light produced directly high pressure system lead buildup urban areas ridge leading widespread low level relative humidity rises percent overnight fog form strong vertically shallow high pressure systems moving higher latitudes lower latitudes northern hemisphere associated continental arctic air masses low sharp temperature lead areas persistent cloud known terms type weather brought anticyclone depends origin example extensions azores high bubble pressure bring winter warmed base trap moisture warmer oceans high pressures build north extend southwards bring clear weather cooled base opposed warmed helps prevent clouds forming highest barometric pressure recorded earth inhg measured december surface weather maps surface weather analysis type weather map depicts positions low pressure areas types scale systems frontal zones drawn maps lines equal temperature drawn normally solid lines preferred temperature interval temperature useful finding fronts warm large temperature plotting freezing line useful determination precipitation type convective systems tropical cyclones outflow boundaries lines analyzed surface weather analyses analysis performed maps involves construction lines equal mean sea level pressure closed lines indicate positions relative pressure field called low pressure areas called high pressure areas high shown low shown areas low pressure plotted thick brown lines trough axis commonly place surface boundaries horse latitudes analyses tropics analysis series arrows oriented parallel wind showing wind motion certain geographic area depict cyclonic flow likely areas low pressure depict flow likely positions high pressure areas area shows location tropics
Pressure system