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TRANSCRIPT
FrontsFronts
By 2/O John JaromahumBy 2/O John Jaromahum
FrontFront
A front is defined as the transition zoneA front is defined as the transition zonebetween twobetween two air massesair masses of differentof differentdensity. Fronts extend not only in thedensity. Fronts extend not only in thehorizontal direction, but in the vertical ashorizontal direction, but in the vertical aswell. Therefore, when referring to thewell. Therefore, when referring to thefrontal surface (or frontal zone), wefrontal surface (or frontal zone), wereferring to both the horizontal and verticalreferring to both the horizontal and verticalcomponents of the front.components of the front.
AirmassAirmass
Click VideoClick Video
Warm FrontWarm Front
A warm front isA warm front isdefined as thedefined as thetransition zonetransition zonewhere a warm airwhere a warm airmass ismass isreplacing a coldreplacing a coldair massair mass
rise, then steadyrise, then steadysteadysteadysteady risesteady riseDew PointDew Point
fair in hazefair in hazepoor, butpoor, but
improvingimprovingpoorpoorVisibilityVisibility
usually none, sometimesusually none, sometimeslight rain or showerslight rain or showers
drizzle or nonedrizzle or nonelightlight--toto--moderate rain,moderate rain,
snow, sleet, or drizzlesnow, sleet, or drizzlePrecipitationPrecipitation
clearing with scatteredclearing with scatteredScSc; occasionally; occasionally CbCb
in summerin summerstratusstratus--typetype
in this order:in this order: CiCi,, CsCs, As,, As,NsNs, St, and fog;, St, and fog;
occasionallyoccasionally CbCb ininsummersummer
CloudsClouds
slight rise, followed byslight rise, followed byfallfall
leveling offleveling offusually fallingusually fallingPressurePressure
warmer, then steadywarmer, then steadysteady risesteady risecoolcool--cold, slow warmingcold, slow warmingTemperatureTemperature
southsouth--southwestsouthwestvariablevariablesouthsouth--southeastsoutheastWindsWinds
After PassingAfter PassingWhile PassingWhile PassingBefore PassingBefore Passing
Cold FrontCold Front
A cold front is defined asA cold front is defined asthe transition zone wherethe transition zone wherea cold air mass isa cold air mass isreplacing a warmer airreplacing a warmer airmass.mass.
Cold fronts generallyCold fronts generallymove from northwest tomove from northwest tosoutheast. The air behindsoutheast. The air behinda cold front is noticeablya cold front is noticeablycolder and drier than thecolder and drier than theair ahead of it. When aair ahead of it. When acold front passes through,cold front passes through,temperatures can droptemperatures can dropmore than 15 degreesmore than 15 degreeswithin the first hour.within the first hour.
loweringloweringsharp dropsharp drophigh; remainshigh; remains
steadysteadyDew PointDew Point
good, except ingood, except inshowersshowers
poor, followed by improvingpoor, followed by improvingfair to poor infair to poor in
hazehazeVisibilityVisibility
showers thenshowers thenclearingclearing
heavy rains, sometimes with hail,heavy rains, sometimes with hail,thunder and lightningthunder and lightning
short period ofshort period ofshowersshowers
PrecipitationPrecipitation
CuCuCbCbincreasing:increasing: CiCi,, CsCs
andand CbCbCloudsClouds
rising steadilyrising steadilyminimum, then sharp riseminimum, then sharp risefalling steadilyfalling steadilyPressurePressure
steadily droppingsteadily droppingsudden dropsudden dropwarmwarmTemperatureTemperature
westwest--northwestnorthwestgusty; shiftinggusty; shiftingsouthsouth--southwestsouthwestWindsWinds
After PassingAfter PassingWhile PassingWhile PassingBefore PassingBefore Passing