|
Can you forecast something about tomorrow's rains in
the rainy season? If you are somewhere along west coasts
of India or Myanmar, in Arunachal Pradesh or Assam or
in a place where it rains about 250 cm together in June,
July and August, there are some easy ways. Follow the
steps below.
(1) Say you are in Panjim (15°29'N, 73°49'E)
in Goa along the west coast of India in the month of
July, the rainiest month here.
(2) It was raining only about 20 mm/day yesterday.
This is roughly average daily rainfall in the rainy
season in many places along west coasts of India. This
is possible only with intermittent light rains, moderate
rains and bursts of sunlight. Thunderclouds and heavy
showers cause about 20 mm in half an hour alone and
hence were absent yesterday.
(3) You want to know whether it would be downpouring
or heavily raining tomorrow with flooded roads, no buses,
trains running out of time etc. You are planning to
go to a far away place by bus to attend a marriage and
return by late evening.
(4) Since it was raining only average rains (about
20 mm/day) yesterday with no heavy downpours and since
today also similar situations seem to prevail with occasional
glimpses of Sun, conditions might be same tomorrow also.
It can be a sunny day also with mild rainfalls (say
about 2 mm/day) or a heavily raining day with about
100 mm/day. Remember, it is July and atmospheric conditions
can change abruptly causing any type of weather!
(5) Now start your personal computer. Go to a meteorological
web site (www.cdc.noaa.gov, www.ncmrwf.gov.in etc.)
and download yesterday's and today's surface pressure
charts. The surface isobars are regularly spaced and
quasi-parallel without any kinks, troughs or lows. Hence,
it is highly probable that tomorrow is going to be of
same nature as today or even with less rains. Okay,
go for the marriage with a smiling face.
(6) Let us see another situation. It was raining heavily,
almost continuously, for the last 2 days. What could
be tomorrow's situation?
(7) Download last 2 days and today's surface pressure
charts. There is a trough which caused heavy rains somewhere
nearby your place or over your place. This trough-feature
in the surface isobars can not run away from your place
very fast. This shifts or moves slowly northwards. Hence
it is going to rain heavily tomorrow also. Have another
check also. Go to the web site of India Meteorological
Department and see the satellite images of clouds for
yesterday and today. There is a very thick, marked cloud
system roughly above the trough. This system would consist
of many tall Cumulus and Cumulonimbus clouds which cause
heavy rains. This is a definite indication of heavy
rains for tomorrow also.
(8) Let us see another situation. Last 6 days it was
raining almost continuously with dark skies and thundershowers.
There were reports of floods and traffic breakdowns.
Today rains are very less and sky is only partially
cloudy. What could be tomorrow's situation? Download
today's and past few days surface pressure charts and
satellite images of clouds. There was a low pressure
system when it rained continuously. But it moved away
and dissipated. Thick clouds are absent today. Now isobars
are regularly spread without any kinks or troughs. Hence
there is high chance that tomorrow would be brighter
with thin rains, say about 2 mm/day.
(9) Many other situations can happen during rainy season.
If one watches sky carefully and guess rightly about
rains, one can do away with umbrella about 50% of times.
Dependable forecasts of similar nature can be done by
even an illiterate farmer without any internet facilities.
But the person should have thorough knowledge of different
clouds, different rains, winds at different heights
and cloud movements etc. from long term visual observations.
Try, make some guesses in the coming rainy season.
10) Watching clouds,rains, sunlight, winds etc. is
good for your mind and body
This can make you closer to nature and natural.
M.J. Varkey
Now retired and available on vadelerkey@sancharnet.in
|
