Fronts are boundaries between two air masses of differing characteristics. There are four main types of fronts: cold fronts, warm fronts, occluded fronts, and stationary fronts. Cold fronts are steep boundaries where cold air overrides warm air, bringing precipitation. Warm fronts are more gradual, with light, continuous precipitation as warm air rises over cold air. Occluded fronts occur when a cold front catches up to a warm front. Stationary fronts have little or no movement as the air masses are parallel.

1. FRONTS
Simran Sehrawat
2145520009
M.A. I Semester
Academic Session: 2018-2019

2. FRONTS
• When two contrasting air masses meet, they form
a front, which is a boundary that separates two
air masses.
• The sloping boundary between two contrasting
air masses of contrasting characteristics in terms
of temperature, velocity, humidity, density etc. is
normally called FRONT.

3. • FRONTOGENESIS- The process associated
with the creation of new fronts or regeneration of
old and decaying fronts already in existence is
called frontogenesis.
• FRONTOLYSIS- The process of destruction or
dying of old fronts is called frontolysis.

4. CLASSIFICATION
• Fronts are classified into four principal types on
the basis of their different characteristic features :
Cold Front
Warm Front
Occluded Front
Stationary Front

5. FRONT SYMBOLS

6. COLD FRONT
• Cold front is advancing ,in which cold air
becomes active and aggressive and invades the
warm air territory and being denser remains at
the ground surface and forcibly uplifts the warm
and light air.
• In simple terms, cold air mass replaces a warm
air mass
• Slope- 1:50 to 1:100
• Cold front is much steeper than the warm front

7. • Associated with bad weather –
Thick clouds
Heavy downpour
Thunderstorms
Lightning
Temperature decreases with the arrival of cold
front, sky becomes overcast with cumulo-nimbus
clouds, heavy precipitation occurs but for short
duration. After the passage of cold front, clouds
disappears, precipitation terminates and weather
becomes clear.

12. WARM FRONT
• In warm front, warm and light air becomes active
and aggressive and rises slowly over cold and
dense air.
• The slope of the front is gradual- 1:100 to 1:400
• As the front approaches the clouds lower and
thickens progressively to cirrostratus, altostratus,
and nimbostratus.

13. • Precipitation- light to moderately heavy and
continuous, extending over a wide zone.
• Gradual increase in temperature and weather
tends to be warm and humid

18. OCCLUDED FRONT
• Occluded front is formed when cold front
overtakes warm front and warm air is completely
displaced from the ground surface.
• There are two ways in which an occlusion may
form –
Cold-front occlusion- when the air behind the
cold front is normally colder than that ahead of
the warm front, as occlusion develops the cold
front overtakes warm front.

19. Warm-front occlusion- where the air behind the
cold front is warmer than that ahead of the warm
front, the retreating (cool) air overtakes the
advancing (cold) air, producing a warm-front
occlusion

28. STATIONARY FRONT
• Stationary front is formed when two contrasting
air masses converge in such a way that they
become parallel to each other and there is no
ascent of air.
• This front doesn’t move either forward or
backward i.e. two air masses are “standoff”
• Temperature remains constant and winds are
gentle
• Several days of altocumulus clouds and likely
precipitation on cold side

31. FRONTALZONES
There are 3 principal frontal zones on the earth’s
surface
Arctic Frontal Zone
Polar Frontal Zone
Inter-Tropical Frontal Zone

32. ARCTIC FRONTAL ZONE
• Created in the arctic areas due to convergence of
continental and maritime polar air masses
• Theses fronts are not very strong and
active(because of less temp. contrast b/w two air
masses)
• Active fronts are formed when relatively warm
polar maritime air mass meets extremely cold
arctic air mass
• These develops along the arctic coasts of Eurasia
and North America

33. POLAR FRONTAL ZONE
• Formed in middle latitudes (in both hemispheres)
because of convergence of polar continental air
mass and tropical maritime air mass
• They are more active in winter seasons while
weakened during summer season (because temp.
contrast is more propounded)
• The temperate cyclones produced along polar
front travel from west to east(because the temp.
contrast b/w two air masses decrease to
minimum)

34. INTERTROPICAL FRONTAL
ZONE
• Acc. To some meteorologists tropical fronts is
formed near the equator due to convergence of
north east and south east trade winds
• However, there is no temperature contrast
between these two air masses(trades) of similar
origin and some properties

37. REFERENCES
• Singh, Savindra. (2016). Climatology, Allahabad, U.P. : Pravalika
Publications
• Critchfield, Howard. J. (2015) General Climatology,(4). Noida,
U.P. : Pearson Indian Education Services Pvt. Ltd.
• https://www.pmfias.com/fronts-frontogenesis-stationary-
front-cold-front-warm-front-occluded-front/
• https://blog.weatherops.com/there-are-four-basic-types-of-
fronts-can-you-name-them
• Images from net surfing