weather map weather map displays meteorological features particular area particular point time symbols specific meanings maps use mid-19th century research weather purposes maps temperature help locate weather fronts maps analyzing lines equal wind speed constant pressure surface jet stream located use constant pressure charts hpa level indicate tropical cyclone motion dimensional based wind speeds levels areas convergence divergence wind field helpful determining location features wind pattern popular type surface weather map surface weather analysis plots depict areas high pressure low pressure cloud codes translated symbols plotted maps meteorological data included reports sent professionally trained observers history use weather charts modern sense began middle portion 19th century order theory storm systems war storm devastated french fleet french scientist able chronological map storm issued path predicted avoided fleet england scientist heard work pioneering weather forecasts gathering information weather stations country month october plotted data map system symbols creating world weather map map prove air circulated clockwise areas high pressure coined term anticyclone describe phenomenon instrumental publishing weather map newspaper modified instrument copying drawings map printing blocks times began printing weather maps methods data introduction country wide weather maps required existence national telegraph networks data country gathered real time remain relevant subsequent analysis use telegraph gathering data weather newspaper led electric telegraph extended far manchester obtain information eastern counties inquiries following places answers returned important time standardized time zones information map accurately represent weather given time standardized time system coordinate british railway network inauguration mean time usa developed network observers central 1840s 1860s took helm inherited network act congress expanded west coast soon data map lack time united_states fully adopted time zones detroit finally established standard time 20th century use frontal zones weather maps began 1910s norway polar theory attributed derived coastal network observation sites norway world war theory proposed main cyclone concentrated lines convergence ahead low trailing low convergence line ahead low known steering line warm trailing convergence zone referred line cold areas clouds rainfall appeared focused convergence zones concept frontal zones led concept air masses nature dimensional structure cyclone wait development upper air network 1940s leading edge air mass changes bore resemblance military fronts world war term came use represent lines united_states began formally analyze fronts surface analyses late opened downtown washington addition surface weather maps weather agencies began generate constant pressure charts united_states began daily weather map series analyzed hpa level metres sea level hpa surface analyzed metres sea level effort map plotting began united_states process complete 1970s hong_kong completed process automated surface plotting computer systems software finally sophisticated allow ability satellite imagery radar imagery model derived fields atmospheric thickness combination surface observations best possible surface analysis united_states development achieved replaced surface analyses national_weather_service combined issued hours combines analyses different centers recent advances fields geographic information systems possible finely tailored products traditional weather map entirely new realm weather information quickly matched relevant geographical detail instance conditions mapped road network likely continue lead changes way surface analyses created displayed years plotting data station model symbolic illustration showing weather occurring given reporting station created station model plot number weather elements small space weather maps maps filled dense station model plots difficult read allow pilots important weather patterns computer draws station model observation location station model primarily surface weather maps weather aloft completed station model map allows users analyze patterns air pressure temperature wind cloud cover precipitation station model plots use internationally accepted convention changed little august elements plot key weather elements including temperature wind cloud cover air pressure pressure tendency precipitation winds standard plotted weather maps century ago winds plotted arrows feathers depicting knots wind feathers sides depicted knots wind changed half arrow half wind indicating knots knots pennant flag knots structure code maximum cloud symbols plotted reporting station appears weather map cloud types coded transmitted trained observers plotted maps low middle high special symbols major cloud type cloud type significant vertical extent occupy coded low middle depending altitude level normally initially forms aside vertical growth takes place symbol map particular observation time genus species variety cloud motion considered important according criteria set elements time observation deemed equal importance type predominant coded observer plotted weather map appropriate symbol special weather maps aviation areas types aviation maps aviation interests set weather maps type map shows visual flight rules effect instrument flight rules effect weather depiction plots ceiling height level half sky covered clouds hundreds feet present weather cloud cover maps depict areas hazard flying aviation related maps areas constant pressure charts constant pressure charts normally contain plotted values temperature humidity wind vertical height sea level pressure surface variety uses mountainous terrain western united_states mexican plateau hpa pressure surface realistic depiction weather pattern standard surface analysis hpa pressure surfaces determine warm upward vertical motion cold downward vertical motion occurring lower portions areas small depressions freezing indicate presence conditions aircraft hpa pressure surface rough guide motion tropical cyclones shallower tropical cyclones experienced vertical wind shear tend steered winds hpa level use hpa constant pressure charts indicate strength systems lower stronger systems near earth surface reflected stronger features levels atmosphere drawn levels lines equal wind speed helpful finding wind pattern wind pattern aloft favorable tropical cyclogenesis wind pattern levels atmosphere locations jet streams areas colder indicate lack significant long active thunderstorm activity surface weather analysis surface weather analysis type weather map depicts positions high 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 boundaries 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 highs shown lows shown elongated 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
Weather map