Weather in a Depression
Name
After Cold Front
Cold Front
Warm Sector
Warm Front
Before Warm Front
Description of
Weather
Rising air pressure
with low
temperatures. Cloud
is clearing away and
the rain stops. There
is a strong northeasterly wind.
There is low air
pressure and the
temperature is falling.
Cumulo-nimbus
clouds bring heavy
rain. The northeasterly winds are
getting stronger
There is low air
pressure and high
temperature. The low
stratus clouds bring
little rain but
sometimes drizzle.
There is a moderate
south-westerly wind.
There is falling air
pressure but rising
temperature. The
thick, low cumulus
clouds bring steady,
prolonged rain. The
light winds swings
round from the SE to
the SW.
The air pressure is
high but falling and
the temperature is
low. The high , thin
cirrus clouds bring no
rain. There are light
south-easterly winds.
Explanation
This stage is on the
edge of the
depression so the
pressure is rising.
The temperature is
low due to the mass
of cold air. There is
no undercutting of
warm air so the air is
not rising. This
means that few
clouds form and little
rain falls.
The cold front is
passing. The
temperature falls as
the cold air moves in.
Cold air is
undercutting the
warm air so the air
rises quickly causing
cooling and
condensation and
clouds to form.
Because the air rises
quickly there is heavy
rain.
This is in the warm
sector so
temperatures are
higher. There is
slowly rising air so
few clouds form
sometimes there is
drizzle. It is near the
centre of the
depression so the
pressure is low.
The warm front is
passing. The warm
air causes
temperatures to rise.
Warm air is rising
slowly over cooler air
causing cooling,
condensation and
clouds to form and
steady rain to fall.
Before the warm front
has passed there is
cool air giving low
temperatures. The
air is sinking so few
clouds form and no
rain falls. This is on
the edge of a
depression so the
pressure is high but
falling
Depression Map
Stage 1
Stage 5
Stage 4
Stage 3
Stage 2
1.
Weather
Rising air pressure
with low
temperatures.
Cloud is clearing
away and the rain
stops. There is a
strong northeasterly wind.
There is low air
pressure and the
temperature is falling.
Cumulo-nimbus
clouds bring heavy
rain. The northeasterly winds are
getting stronger
There is low air
pressure and high
temperature. The low
stratus clouds bring
little rain but
sometimes drizzle.
There is a moderate
south-westerly wind.
There is falling air
pressure but rising
temperature. The
thick, low cumulus
clouds bring steady,
prolonged rain. The
light winds swings
round from the SE to
the SW.
The air pressure
is high but falling
and the
temperature is
low. The high,
thin cirrus clouds
bring no rain.
There are light
south-easterly
winds.
Depression - Cross section and explanation
Explanation
The temperature is
low due to the mass
of cold air. There is
no undercutting of
warm air so the air is
not rising. This
means that few
clouds form and little
rain falls. This stage
is on the edge of the
depression so the
pressure is rising
The cold front is
passing. The
temperature falls as
the cold air moves in.
Cold air is
undercutting the
warm air so the air
rises quickly causing
cooling and
condensation and
clouds to form.
Because the air rises
quickly there is heavy
rain.
This is in the warm
sector so
temperatures are
higher. There is
slowly rising air so
few clouds form
sometimes there is
drizzle. It is near the
centre of the
depression so the
pressure is low.
The warm front is
passing. The warm
air causes
temperatures to rise.
Warm air is rising
slowly over cooler air
causing cooling,
condensation and
clouds to form and
steady rain to fall.
Before the warm front
has passed there is
cool air giving low
temperatures. The
air is sinking so few
clouds form and no
rain falls. Stage 1 is
on the edge of a
depression so the
pressure is high but
falling