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Speaker : Dr. Someshwar Das

Monti: Good Morning Sir
Monti:
Why are there thunderstorms?
Dr. Someshwar Das:
Welcome to today'a chat session "Thunder storms". Dr. Someshwar Das is here with us to answer your queries. Please log on and enjoy the interaction with him.
Dr. Someshwar Das: Good Morning Monti, Do you have any question to ask?
Monti:
Sir, please rply my question
Dr. Someshwar Das:
Monti, Thunderstorms occures whenever there is strong instability in the atmosphere. Thunderstorms act as a mechansim to release the atomospheric instability
Dr. Someshwar Das:
Hello, Gaurav,
Dr. Someshwar Das: Hello Ashish welcome to the chat session
gaurav:
hel sir
shruti:
sir what is instability
ashish rajwadi:
hello sir , i have my class ix students with me and we would like to interact with you
gaurav:
How Can I Protect Myself From a Thunderstorm or Lightning?
Monti:
Sir,Is Thunderstorms helps keep the Earth in electrical balance???
gaurav:
hello*
Dr. Someshwar Das:
Ashish you are welcome to interact with Dr. Das
Dr. Someshwar Das:
Gaurav keep your self away from tall trees and electrical poles and pointed objects.
Dr. Someshwar Das:
Monti, yes it does.
ashish rajwadi:
what is the cause of thunderstorm and what amount of voltage it generates?
Monti:
How it helps to keep the electric balance?
Dr. Someshwar Das:
Monti approximately 100 flashes per second occur
shruti:
Sir how we know that which area is sensitive
psf:
Is it true that hilly areas are more sensitive to thunderstrikes?
pawan: hello sir
Dr. Someshwar Das:
Ashish, It can generate 30k amperes of electrical current is discharged during a lighting flash.
Dr. Someshwar Das:
The potential difference caused by lighting is about 100 m volts. This is enough to light 100 watts bulb for 2 months.
ashish rajwadi:
if its so high then how lightining conductor is able to protect us from it ?
Dr. Someshwar Das:
Psf hills facilitate the growth of clouds which when becomes deep enough can cause thunderstorms
Dr. Someshwar Das:
Ashish The lightning conductor helps propogate strong charges to the earth which is generally negatively charged.
Monti:
Where can I find out information about a storm?
ravindra: Hello sir
ashish rajwadi:
how clouds gets charged and why do they occur only in monsoon ?
ravindra: only one question. What is the reason behind thunding a cloud means why a clound thundring
amit: hello sir
pawan:
what r the equipments which measure thunderstorms
Dr. Someshwar Das:
monti, the India Meteorological depatment provides forcast for possible area of thunderstorms besides that you can also obtain information about storms from media, newspaper, TV, Internet etc.
Monti:
What is a Severe Thunderstorm or Tornado Watch?
 ravindra: Sir i am waiting for ur reply
Dr. Someshwar Das:
Ravindra during the lightning flash atomospheric collumn gets heated approximately by about 20,000 Degree C which causes shock waves the air is expanded in a fraction of seconds which generates accoustic waves that we hear as thunder.
 wolfoid: Sir, If I fly a hydrogen balloon with a metallic wire, how can I protect myself from lightening electrocution?
ashish rajwadi:
can thisjelectrcity be used for useful purpose
 Dr. Someshwar Das: Monti, severe thunderstorm watch is given to take precausion against possible strikes by thunderstom or Tornado
Dr. Someshwar Das:
Wolfoid, If you fly a hydrogen balloon with metallic wire is likely you are inviting troubles.
wolfoid: Sir, but thereshould be some protective mechanism. we fly wire antennas for radios
ravindra: thank u sir but in high school we had read When two opposte charged cloud come near to each other there is a electric spooling is occure that we hear thunder. is it wrong sir?
wolfoid: We want to know about any device which can be fitted to the wire so that our equipment does not get damaged. do you have any idea abot such devices?
ashish rajwadi:
is there any sign that lightining is going to strike and how to protect ourselves
Dr. Someshwar Das:
Ashish it would be fantastic if we could utilise the elctric energy generated during a thunderstorm but so far it has not been utilized.
wolfoid:
Basically we tie a copper wire to the hydrogen balloon and let the balloon fly. Just like Guglielmo Marconi did during his transatlantic communication i 1901
Monti:
Why does it rain on one side of the street and not the other?
Dr. Someshwar Das:
Ravindra, Inside a cloud there are regions of both postive and negative charges . when the potential difference between positive and negative charges exceed a thereshold value lightning and thunder can occuer. Therefore it is not that two clouds of opposite charges should collide to generate lightning.
ravindra:
how to determine whether the thunderstorm ordinary and severe?
Dr. Someshwar Das:
Wolfoid In 18 & 19 Centuries people use to fly kites and balloons tied with equipments to measure electrical charges inside the clouds.
ashish rajwadi:
what is the cause of these charges on the cloud?
Dr. Someshwar Das:
Ravindra when thunderstorm has squall speed of about 150 - 200 km per hour it is called a severe thunderstorm
Prabhu:
Hello Sir,
Prabhu:
What environmental parameters are most often observed with organized severe weather?
Dr. Someshwar Das:
Monti, Thuhderstorm are very small scale phenomena ( 1- 10 km horizental scale) Thus if it rains below thunderstorms on one side of the street the other side may be dry.
Monti:
What is SKYWARN?
Ishwar: What is a derecho?
Dr. Someshwar Das:
Ashish, inside a cloud there are different kinds of water droplets, ice particles and a lot of processes are taking place . During the updraft and downdraft ice particles can brake down . The ice particles generally have negative charge at its core so when a break up takes place charges are separated.
ashish rajwadi:
thank you sir for your answers atul vidyalaya students express their thanks
gaurav:
sir, How does lightning form?
Dr. Someshwar Das:
Prabhu, During a severe weather we observe wind speed Wind direction, temperature, moisture and many other fields.
anju:
hello sir
gaurav:
and what does thunder have to do with lightning?
gaurav:
sir, How does lightning form and what does thunder have to do with lightning?
Dr. Someshwar Das:
Gaurav lightning is equivalent to an electrical spark that you observe in your home when you touch two wires of opposite charges.
Dr. Someshwar Das:
Similar spark can take place in the atmosphere when huge amount of opposite charges accumalate inside the cloud.
alok_mukherjee:
Can visible ,infrared or water vapour imagery help to forcast or predict thunderstorms.
ravindra:
what about the sound of thunder?
Dr. Someshwar Das: Gaurav lightning and thunder always occur together both you see the lightning before you hear thunder. because the speed of the light is much higher than the speed of the sound.
Dr. Someshwar Das:
Alok, yes we can easily distinguish between an ordinary cloud and a thunder cloud in the satellite pictures of visible infrared and water vapour imagery.
alok_mukherjee:
In field observations other than TELEx, IHOP2002, are there projects focusing Indian subcontinent.
alok_mukherjee:
Thanks, Dr. Das.
Dr. Someshwar Das:
Ravindra yes i said before when a lightning is dischared atmospheric air gets heated enormously by about 20,000 Cenigrat causing shock waves in the atmophere which inturn gerate acoustic waves that we hear as thunder.
alok_mukherjee:
By thunderstorms Nitrous oxide is created, does this have an effect on tropospheric ozone.
Dr. Someshwar Das:
Alok yes the govt of India is organizing a STORM project in collaboration with several Institutes and Reserch organisation in India to conduct field experiments for observations and modeling of thunderstorms
alok_mukherjee:
Where are severe thunderstorms most common? What is the frequency of winter thunderstorms.
ravindra:
sometimes it is obsevered that lightning is from cloud to ground and sometimes it is from cloud to cloud lightning. why?
 Dr. Someshwar Das: Alok yes atomospheric Ozones is affected by the relase of Nitrous oxide release during thunderstorms . NO2 are also useful to agriculture.
alok_mukherjee:
I feel convinced, Dr. Someshwar. Thanks
alok_mukherjee:
Why does some thunderstorms have a greenish hue?
Dr. Someshwar Das:
Alok severe thunderstorms are most common during pre-monsoon seasons (April - May) over the W. Bengal region they are also known as Norwesters and Kalbaisakhi (local name). but they can also occure during winter associated with the Western disturbance.
 alok_mukherjee: Why does the sky sometimes turn orange after a thunderstorm?
Dr. Someshwar Das:
Alok,the colour that you see depends on the sun rays reflected from the clouds.
alok_mukherjee:
What is a supercell?
Dr. Someshwar Das:
Alok, Supercell is a line of severe thunderstorms covering an area of about 10 - 100 Kms they are also called squall lines. They are generated when there is strong instability in the atmosphere . Some time one cell can trigger the formation of another cell causing a series of cumulonimbus clouds to form.
alok_mukherjee:
Do all thunderstorms have hail?
Dr. Someshwar Das: Surya welcome to the chat session.
alok_mukherjee:
What is a derecho?
Dr. Someshwar Das:
Alok, all thunderstorms need not have hail. Hails formed inside deep thunder clouds where there is strong updraft and downdraft which helps sustaine a waterdroplet for long time inside the clouds. During the cirulation process the droplets keep growing insides and freeze when they are taken above the freezing level.
alok_mukherjee:
Time is less, and questions endless, sorry for multiple posting, Dr. Das.
Dr. Someshwar Das:
Welcome Dr Mukhopadhyay
Dr. P. Mukhopadhyay:
Hi Thanks
shruti:
bye sir thank u
Dr. P. Mukhopadhyay:
Can you just tell some time we see a long lull in thunderstorm activity even though there is substantial CAPE
Dr. Someshwar Das:
Alok can you elaborate Derecho
alok_mukherjee:
Where can I find out information about a storm?
Dr. Someshwar Das:
Dr Mukhopadhyay even if there is cape in the atmosphere it may not have enough mechanism to relase them inother words unless we have a triggering to release the cape thunderstorms do not occure.
alok_mukherjee:
derecho, as I heard is perhaps, a fast-moving windstorm that is made up of thunderstorms that repeatedly develop along the leading edge surya: Can both the values of CAPE and CINE be zero at a certain synoptic hour during pre-monsoon period?
Dr. Someshwar Das: Alok as I said before you can get information about a storm from Weather Forcast from Media, TV, Newspapers, Internet etc. There are many books on clouds and thunderstorms.
Dr. Someshwar Das:
Surya It can be possible.
Dr. Someshwar Das:
Alok thanks you have answered your question.
alok_mukherjee:
Dr. Das thanks.
surya:
Is it possible for a perfectly stable atmosphere? What are the other conditions during which it is possible?
Dr. P. Mukhopadhyay:
Dr. Somesh I think time is alomost over. Thanks for the live chat. Let's have more so in future.
Dr. Someshwar Das:
Dear all, we can have many more chat sessions about thunderstorms . You can also ask me by email if you have question related to this . My email is somesh@ncmrwf.gov.in
Dr. Someshwar Das:
Surya yes it is possible to have perfectly stable atmosphere in rare cases.
Dr. Someshwar Das:
Thank you all for joining the chat session. If you observe please let me know any interesting things that you have found.
Dr. Someshwar Das:
If you observe thunderstorm please let me know any interesting thing you have found.
 ravindra: thanks sir
gaurav:
thankyou very much sir...
surya: Than You Sir.