Rainfall is a term used to refer to water
falling in drops after condensation of
the atmospheric vapour. The term is
also used to refer to the quantity of
precipitation falling in an area within a
given period of time.
Monsoon winds are seasonal winds which
blow during summer and winter. The summer
winds are called South-west monsoons and
the winter winds are called North-east
South-west monsoon are giant sea breezes
which bring rainfall. The rains began when the
ocean are less heated and land is more heated.
The air from the land rises developing a low
pressure and it attracts the cool air causing
heavy rainfall. The southwestern summer
monsoons occur from June through September
North-east monsoons blow from the land towards
Monsoon and Pakistan
Pakistan receives the tail end of the monsoon.
Which enter the Pakistan after crossing India
they usually reach Pakistan in early July and continue to September.
Since the monsoon come into Pakistan
from the East.
The eastern part receive more rainfall
in the monsoon,
the main monsoon enter Northern
Punjab while the secondary
Southern Punjab and Sindh.
The highest rainfall during
the monsoon season as receive
by Murree that is 850mm.
The western depression winds blow from
the Mediterranean sea in the winter and
after passing through Iran and Afghanistan
they enter in the western area of Pakistan
and cause rainfall.
The Western depression enter Pakistan from the west after
passing through Iran and Afghanistan, most of their moisture is
lost on their long land journey. Therefore they bring a small
amount of rainfall to Pakistan in spite of this the western parts
of western highlands receive more rainfall from the western
depression then from other sources.
Because of Western Depression Northern Punjab,
the hilly areas of kpk and Northern Baluchistan receive
125 to 250mm of rainfall.
Sindh is the driest area where in most parts the rainfall is
less then 25mm.
Rain fall from western depression begins in December and
continues up to March.
Western depression and Pakistan
This happens when hot air rises from
the hot land into the air. This air is high
in moisture, and causes a lot of
condensation when it reaches the
in rainfall in different
areas in summer.
Convectional currents cause some degree of
rainfall in Pakistan during the summer months.
This condensation results in rainfall in the
northern and north-westren parts of Pakistan in
the summer. The southern parts of Pakistan are
deprived from convectional currents due to a
temperature inversion layer
Relief rain usually takes place around coastal
areas where a fleet of hills runs along to the
coast. When wet onshore wind from the sea meet
a mountain, hill and barrier, it is forced to rise
along the slope and cools. When the air
temperature falls to its dew point, water vapor
condenses to form clouds. When the clouds can
no longer hold the water droplets, relief
rain begins to fall on the windward slope of
Relief rainfall and Pakistan
Cities like Murree and Kakul continually receive
rainfall due to this while Gilgit and Chitral do not
as they fall in the rain shadow areas.
A tropical cyclone is a rapidly-rotating storm
system characterized by a low-pressure center,
strong winds, and a spiral arrangement of
thunderstorms that produce heavy rain,
can cause a lot of destruction.
Tropical cyclones and Pakistan
They originate in Arabian Sea quite often but rarely
reach the coast of Pakistan. Therefore, this source of
rainfall is totally unreliable.