Cold Front: transition zone from warm air to cold air - WW2010

A cold front is defined as the transition zone where a cold air mass is replacing a warmer air mass. Cold fronts generally move from northwest to southeast. . ColdFront transitionzonefromwarmairtocoldair Acoldfrontisdefinedasthetransitionzonewherea coldairmass isreplacingawarmerairmass. Coldfrontsgenerallymovefromnorthwesttosoutheast. Theairbehindacoldfrontisnoticeablycolder anddrierthantheairaheadofit. Whenacoldfrontpassesthrough, temperaturescandropmorethan15degreeswithinthefirsthour. Symbolically,acoldfrontisrepresentedbyasolidlinewith trianglesalongthefrontpointing towardsthewarmerairandinthedirectionofmovement. Oncoloredweathermaps, acoldfrontisdrawnwithasolidblueline. Thereistypicallya noticeabletemperaturechangefromonesideofacoldfront totheother.Inthemapofsurfacetemperaturesbelow, thestationeastofthe frontreportedatemperatureof55degreesFahrenheitwhile ashortdistancebehindthefront,thetemperaturedecreasedto38degrees. Anabrupttemperaturechangeoverashortdistanceisagoodindicatorthat afrontislocatedsomewhereinbetween. Ifcolderairisreplacing warmerair,thenthefrontshouldbeanalyzedasacoldfront. Ontheotherhand,ifwarmerairisreplacingcoldair,thenthe frontshouldbeanalyzedasa warmfront.Commoncharacteristicsassociated withcoldfrontshavebeenlistedinthetablebelow. BeforePassing WhilePassing AfterPassing Winds south-southwest gusty;shifting west-northwest Temperature warm suddendrop steadilydropping Pressure fallingsteadily minimum,thensharprise risingsteadily Clouds increasing:Ci, CsandCb Cb Cu Precipitation shortperiodofshowers heavyrains,sometimeswithhail,thunderandlightning showersthenclearing Visibility fairtopoorinhaze poor,followedbyimproving good,exceptinshowers DewPoint high;remainssteady sharpdrop lowering Tableadaptedfrom:Ahrens,(1994) Fronts Termsforusing dataresources. CD-ROMavailable. CreditsandAcknowledgmentsfor WW2010. DepartmentofAtmospheric Sciences(DAS) attheUniversityofIllinoisatUrbana-Champaign. windshift