The Weather and Meteorology thread

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Delhi Monsoon, Weather Today Live Updates: Monsoon hits Delhi; several areas witness waterlogging, traffic jams
Delhi Weather Forecast Today, Delhi Monsoon Live News Updates: The much-awaited Southwest Monsoon finally brought respite from scorching summer temperatures as 28.1 mm rainfall was recorded between 8.30 am and 5.30 pm.

By: Express Web Desk | New Delhi |
Updated: July 13, 2021 9:34:07 pm


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Delhi Weather Forecast Today, Delhi Monsoon Live News Updates: After several false starts, the monsoon finally hit Delhi on Tuesday. The first showers of monsoon caused waterlogging and massive traffic jams in different parts of the city, causing snaking lines of vehicles on several busy road stretches, including at the Dhaula Kuan Ring Road, Barapullah and Kallindi Kunj flyovers.

The much-awaited Southwest Monsoon finally brought respite from scorching summer temperatures as 28.1 mm rainfall was recorded between 8.30 am and 5.30 pm.

The rainfall started on Monday night and continued through Tuesday morning. By 8.30 am, Lodhi Road met station had seen 19.4 mm of rain, followed by 2.5 mm at Safdarjung and 2.4 mm at Palam. Monsoon was set to arrive in the national capital on June 27, but it got delayed by 15 days, first time in almost two decades.

The IMD called the failure to predict the monsoon in Delhi with accuracy “rare and uncommon”. On Monday, the monsoon advanced to several parts of Rajasthan, including Jaisalmer, but gave Delhi a miss yet again.


The IMD had earlier announced that the city would see monsoon rains much earlier than usual on June 15. However, changes in conditions that promote the advancement of moisture-laden winds meant that there were delays, and IMD’s monsoon forecast for rains was wrong at least thrice.

Delhi Monsoon, Weather Today Live Updates: Monsoon hits Delhi; several areas witness waterlogging, traffic jams
 
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It will start from Saturday Night to Sunday - All Day




Saturday Night :

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Sunday Morning 5.30 am:

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Sunday Morning 11.30 am:

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Sunday Evening 5.30 pm:

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Sunday Night 11.30 pm:

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Near Manali, 400 trekkers sent back for ignoring weather warning

TNN / Updated: Jul 14, 2021, 07:31 IST


MANALI: A day after an MBBS student from Kullu drowned in an overflowing rivulet while trekking near Manali’s Hamta village, nearly 400 trekkers from various states, who had been trekking in the area after ignoring a government warning, were sent back on Tuesday.
Officials from police, forest and other departments, along with locals and members of Adventure Tour Operators Association (ATOA), Manali, were succesful in fundung the missing woman’s body. In spite of the incident, a large number of tourists had been making a beeline for Hamta Pass. Some had permission from forest department, but others were trekking illegally. Officials sent back the trekkers to Manali after a warning.
The department of tourism on Monday had issued an alert that all adventure activities, including rafting, paragliding and trekking, shall remain suspended for two days due to inclement weather conditions. The department has also imposed two-month ban on all adventure activities from July 15. ATOA officials say local operators are following government orders, but companies from other states are ignoring warning.
District tourism development officer Krishan Chand said all adventure activities had been suspended with immediate effect on Monday and Tuesday, following inclement weather forecast by IMD. “All activities will be banned from July 15 to September 15 as precautionary measures during monsoon season. Strict legal action will be taken against those not adhering to the orders,” he said.
ATOA Manali president Ravi Thakur said large companies from many other states were organising mass treks in the region. “They have turned serene mountains into towns. They organise treks for groups of 50 or more, which is more like a yatra, not adventure. They do not follow safety procedures. They do not know about mountaineering. Also, 90% trekking in the region is being organised by unprofessional, large companies. When their clients are in trouble, we go for their rescue,” he said.
Thakur said they will not allow mass trekking in the area. “We have to promote safe and eco-friendly adventure activities. These companies are here only to earn money at the cost of environment and precious lives. We reached Hamta on Monday evening to search for the missing trekker. We were surprised to see that trekking was happening even at night. Trekkers walking in large groups broke our hearts. We shall now fight for streamlining trekking with proper safety procedures and won’t allow anybody to destroy environment,” he added.

Near Manali, 400 trekkers sent back for ignoring weather warning | Chandigarh News - Times of India
 

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IMD predicts heavy rainfall in country next week
Source: PTI - Edited By: Utkarsh Mishra
July 16, 2021 23:51 IST


A swelled up Mithi river forced the evacuation of 250 people in rain-battered Mumbai's Kurla area on Friday, even as the temperatures were above normal in several parts of north Indian plains in the absence of rainfall despite the revival of the Southwest Monsoon.



IMAGE: Vehicles wade through a flooded road after heavy rains at Kadutthuritthi in Kottayam district, on Friday. Photograph: PTI Photo

Very light rains and thundershowers occurred at isolated places in Uttar Pradesh though, and a fresh warning of heavy showers was issued in Himachal Pradesh as the India Meteorological Department (IMD) said heavy to very heavy rainfall is likely in several parts of the country, including the northern region, over the next six-seven days.
The meteorological department said rainfall activity is very likely to increase with fairly widespread to widespread rainfall and heavy to very heavy falls over the western Himalayan region and Uttar Pradesh from July 17 to 20.
Heavy falls are also expected over Punjab, Haryana, east Rajasthan and north Madhya Pradesh from July 18 to 20 and isolated heavy rainfall over Delhi on July 18, it said, adding that isolated extremely heavy falls are also likely over Uttar Pradesh on July 18, Jammu on July 19, and Uttarakhand on July 18 and 19.
"Moderate to severe thunderstorm with lightning very likely at isolated places over Gujarat, Madhya Pradesh and south Rajasthan during next 24 hours. They may cause injuries leading to casualties to people and animals staying outdoor," the IMD said.

It said widespread rainfall with isolated heavy falls are also very likely to continue over the west coast and remaining parts of west peninsular India except over Gujarat during the next six-seven days. Heavy to very heavy falls are very likely over Konkan, Goa, ghat areas of central Maharashtra, Karnataka, Kerala and Mahe during same period, the IMD said.
Heavy rainfall is also expected over northeast India, it added. Widespread rainfall with isolated heavy falls is likely over northeast India and sub-Himalayan West Bengal and Sikkim till July 19 which will decrease in intensity and distribution thereafter, the IMD said.
In Delhi, the maximum temperature settled at 37.8 degrees Celsius, three notches above the season's normal, on Friday, and the minimum temperature was recorded at 27 degrees Celsius.
The weatherman predicted partly cloudy skies with light rain or thundershowers for Saturday.
In Himachal Pradesh, the Met office issued a yellow warning for heavy rains, thunderstorm and lightning in the plains, low hills and middle hills on Saturday. It also issued an orange warning for heavy to very heavy rains, thunderstorm and lightning for July 18-20.
Several parts of the state received light to moderate rains during the day. Sarkaghat gauged 86 mm of rainfall, followed by 52 mm in Nadaun, 49 mm in Jogindernagar and 29 mm in Baijnath, 27 mm in Sujanpur Tira, 19 mm in Kasol, 16 mm in Hamirpur, 14 mm in Bhoranj, 13 in Rampur, 11 mm in Sarahan, 9 mm in Palampur and 4 mm in Mandi, the weather office said.
The maximum temperatures in Haryana and Punjab rose on Friday after a few days of respite brought about by monsoonal rains, with joint capital Chandigarh recording a high of 36.8 degrees Celsius, three notches above normal.
Ambala in Haryana recorded a maximum temperature of 36.5 degrees Celsius and Hisar 38.1 degrees Celsius. In Rohtak, it was 37.3 degrees Celsius, 37.8 degrees Celsius in Gurgaon and 35 degrees Celsius in Karnal.
In Punjab, Amritsar recorded a maximum of 35.6 degrees Celsius, Ludhiana 36.7 degrees Celsius and Patiala 36 degrees Celsius.
According to the Met department forecast for Haryana, heavy to very heavy rain is likely at isolated places on July 18, 19 and 20. The forecast for Punjab says heavy rain is likely at isolated places on July 18, and heavy to very heavy rain at isolated places on July 19 and 20.
In Uttar Pradesh, very light rains along with thundershowers occurred at isolated places. The temperature rose markedly in Moradabad division, while no large changes were seen in the remaining divisions of the state.
The highest maximum temperature in the state was 39.8 degrees Celsius, recorded at the Banda observatory, while the lowest minimum was 24.3 degrees Celsius, recorded at the Muzaffarnagar observatory.
In the western coast, heavy rains pounded Mumbai, especially its suburbs, since Friday morning.
Civic body officials said Mumbai island city recorded 55.3 mm rain as the Eastern and the Western suburbs received 135 mm and 140.5 mm downpour respectively between 4 am and 9 am.
Due to the downpour, several low-lying areas in the eastern and the western suburbs witnessed waterlogging, which led to traffic snarls on arterial roads.
As a result of water-logging, mainly between Sion and Vidya Vihar section on the Central Railway's main line, and Chunabhatti-Tikal Nagar section on the Harbour line, the suburban train services were badly affected.

Tulsi lake, one of the seven reservoirs that supply drinking water to the metropolis, overflowed due to heavy rains, officials said.
In Karnataka, a massive landslip occurred near a tunnel on the Kulshekar-Padil stretch of the railway track from Mangaluru to Thokur following heavy rains in the last few days, affecting all trains on the Konkan route.


IMD predicts heavy rainfall in country next week
 

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'Rainfall is one of the hardest things to predict'
By Shivanand Kanavi
Last updated on: July 16, 2018 09:02 IST



'Temperature and wind can be predicted more easily than rainfall.'
'Rainfall, as common experience suggests, is very spotty.'
'The last bit of physics required that tells us whether it is going to rain or not is very hard.'
Professor Roddam Narasimha, the eminent scientist, explains the monsoon, climate change and global warming, in a fascinating conversation with Shivanand Kanavi.




IMAGE: School children use a huge pan to commute in a flooded area in West Bengal's Birbhum district during the 2017 floods. Photograph: PTI Photo

Professor Roddam Narasimha, FRS, is a distinguished aerospace scientist, and among the first few Indian engineers to be elected to several leading international academies like the Royal Society, the US National Academies of Sciences, National Academy of Engineering and the American Academy of Arts and Sciences.
He has contributed enormously to the development of aeronautical and space sciences in India.
Presently at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, one of his current areas of research is cloud evolution and dynamics, a subject of great relevance to the Indian monsoon and global climate change.
A conversation between Shivanand Kanavi and Professor Roddam Narasimha. The first of a two-part feature:




Formation of greenhouse gases

What fascinates you about clouds and what are the unsolved issues there?

Clouds are central to two major problems today -- one is climate change.
The largest uncertainty in the prediction of climate change has to do with clouds.
In the research done by different groups in the world, about which way the atmosphere may go as you emit more greenhouse gases and various other substances into the atmosphere, every now and then something happens that doesn't agree with what is predicted.
The last ten years are a good example.
So there are always sceptics who say 'those models are no good and that you are just making alarmist statements.
If you can't explain why the earth's temperature hasn't gone up in the last 10 years, how can we believe anything you say!'




Climate change


Michael Crichton wrote a novel, and half of it is a polemic about climate change. Have you read it, it is quite interesting?

Yes, it is quite interesting.
Actually some physicists are also sceptics.
The general view in the atmospheric science community is: 'Yes, every now and then there are blips. We do not claim to predict every blip that occurs in it. But after the blip, we can explain what is happening.'
This (the blip) is not going to prevent warming of the planet on the whole, or climate change.'



IMAGE: A villager carries grain on a banana raft as he shifts from a flooded village in Bihar's Araria district during last year's floods. Photograph: PTI Photo


Is global warming certain now?

It depends on whom you ask. The atmospheric scientists are pretty convinced. They say forget about the details.
Just look at how the weather is changing. The Arctic is melting, nobody can doubt that, the evidence is very strong.
Or if you look at the extremes of weather, the frequency of the extremes is increasing. There, the evidence is very strong.
Now, that would be consistent with what the models are saying. Basically, the change in the extremes would be more noticeable than the change in the average.
So, even a degree or two might not change the mean rainfall here very much.
If you look at the monsoons of the last twenty years, extremes of a certain kind are more common.
So, atmospheric scientists say it is dangerous to ignore that this may be a possibility.
But, as I said, there are other people who argue against it and there are some pretty well-known physicists who argue against it.




IMAGE: Army personnel rescue residents from a flooded area in Chennai, December 15, 2015. Photograph: PTI Photo

What about earth scientists, oceanographers?

I think by and large earth scientists are more or less convinced that this is happening.



IMAGE: The Wildlife Trust of India conducting rescue operations trying to rescue rhinos in the Kaziranga National Park in Assam.

The 2016 floods left 80 per cent of the Kaziranga National Park under water, forcing rhinos to find dryer land. Photograph: Kind courtesy @wti_org_india/Twitter


Who is not convinced?

A large number of businessmen are not convinced.



A scientist monitors climatic conditions at the India Meteorological Department in New Delhi. Photograph: Anindito Mukherjee/Reuters


Within the scientific community?

Within the scientific community a small group of physicists who are quite distinguished, I wouldn't say they are people who don't know anything and it comes from the way they do physics.
In physics generally a question has either yes or no as the answer. And so they will want some clinching evidence.
Their point may be translated as 'there is no clinching evidence in favour of climate change. It is variable, but we have always known that it is variable.'
'There is not even strong evidence that the variability has changed,' they would say.
But the people who look at extremes say the evidence is getting stronger and stronger. It is stronger than it was ten years ago.



Overcast sky during the day it is a bit cooler, but during the night an overcast sky is warmer


But it is still based on just 100 years of reliable data?

You are quite right that is a problem. So the debate goes on.
However on clouds everybody agrees.
What is the greatest uncertainty in these climate models?
The greatest uncertainty is clouds, particularly the interaction of clouds with radiation. It is complex.
For example, if you have an overcast sky during the day it is a bit cooler because the solar radiation is not coming down to us, it is getting reflected back.
But during the night an overcast sky is warmer.
Why? The sun is not there, but the Infrared from the ground gets reflected back from the clouds.
So, an overcast day is pleasant, an overcast night is warm.
This is a spectacular everyday example of how clouds interact with the radiation.
So a lot of uncertainty is because of this interaction.
The monsoons are of great interest to India and increasingly everywhere in the world.
Over the last 20 years, people have discovered other monsoon-type climates in the world.
Till now, the monsoon meant the Indian monsoon, but now you have to say 'Indian Monsoon', because there is also an Australian monsoon, also an African monsoon, although they are not of the same scale as the Indian monsoon.


A man pedals his cycle rickshaw during the monsoon in New Delhi. Photograph: Cathal McNaughton/Reuters

Is the monsoon specific to the Indian subcontinent or is it also present in other parts of Asia?

They are elsewhere, but they are on a smaller scale.
Now there is a more general definition of monsoon that it is a switch in circulation and it is a fairly rapid switch in circulation at a certain point of the year and it occurs every year at around the same time.
That it is a cycle, so it switches on around early May late June and it switches off around September in case of the South-West monsoon.
So it depends largely on the contrast between land and sea.
So if you define it that way, as a seasonal switch in oscillation, you will find more than one.



IMAGE: People push a BEST bus on a water-logged street after heavy rainfall in Parel, central Mumbai, July 9, 2018. Photograph: PTI Photo


And the atmospheric circulation, when it brings moisture, you get rain?

Correct. When it comes in from the sea, it brings moisture and you get rain.
In monsoon regions like India the general interest is not in the temperature or wind, it is rainfall.



IMAGE: A picture tweeted by Western Railways of flooded railway tracks in Mumbai, July 10, 2018. Photograph: Kind courtesy @WesternRly/Twitter


So if you look at Cambodia, Vietnam, Laos...

They have South-East Asian monsoon, it is the same thing.
If you live in England, rainfall is not a major variable. It rains almost every day.
It is a drizzle most of the time, so they are worried about temperature.
In India, we don't worry about temperature, because it is warm most of the time.
Our variable is rainfall. Rainfall is one of the hardest things to predict.
Temperature and wind can be predicted more easily than rainfall. Rainfall, as common experience suggests, is very spotty.
It can be raining here in Malleshwaram, but not on the old Airport road in Bengaluru.
So, in space and time it is very spotty.
The last bit of physics required that tells us whether it is going to rain or not is very hard.



Precipitation of rain


There is moisture, which you can measure, but under what conditions will it precipitate? Is that they key unknown?

Yes, under what conditions will it precipitate, is the key thing, and how much and where.
If you ask a physicist about condensation he will say we know the law, it was discovered more than 100 years ago.
At each pressure, there is a particular temperature at which water vapour will condense into liquid water.
But that is not enough.
Most of these cumulus clouds, or the kind that you see in Bengaluru and most parts of India during the monsoon, are actually flow clouds.
They are bubbling up from the ground. And therefore there is a very complex fluid dynamics associated with it, it is not just thermodynamics.
This is fluid dynamics and thermodynamics interacting.
So you can very crudely say, a cloud starts with a warm patch on the ground, light air rises and if it is moist, at some stage, it will reach the condensation temperature and condense.




Photograph: Sahil Salvi


Gets heavier and comes down?

No, it doesn't get immediately heavier. All clouds don't rain.
If the convection is sufficiently strong it will just carry it up.
If you keep condensing more and more, at some stage all the water vapour has condensed already.
For it to fall as rain, the droplets have to get bigger. Big enough that their weight will make them fall.
If they are very small drops, they won't fall, they will be carried with the wind.
Only if the drops are large they will fall against the upward flow within the cloud.
And that has not been understood to this day.
Because, clouds interact in a very complicated way with the air outside.
Suppose you induct a lot of air from the outside and you have moist air inside, even if it has condensed the air from outside will dilute the cloud.
It is dry air. Therefore, clouds and precipitation are still an unsolved problem.


Production: Ashish Narsale/Rediff.com


'Rainfall is one of the hardest things to predict'
 
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'We are more interested in the monsoon than anyone else in the world'
By Shivanand Kanavi
July 16, 2018 08:56 IST


'It affects our economy, it is very important in many ways.'
'So we have to be the foremost experts in the world on the monsoon.'
'But the best minds in India have not devoted their time to the study of monsoon and they have followed the fashions of the West.'




IMAGE: Why walk when you can swim! A boy swims through a water-logged street in Sion, north central Mumbai. Photograph: Sahil Salvi

Professor Roddam Narasimha, FRS, is a distinguished aerospace scientist, and among the first few Indian engineers to be elected to several leading international academies like the Royal Society, the US National Academies of Sciences, National Academy of Engineering and the American Academy of Arts and Sciences.
He has contributed enormously to the development of aeronautical and space sciences in India.
Presently at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, one of his current areas of research is cloud evolution and dynamics, a subject of great relevance to the Indian monsoon and global climate change.
Shivanand Kanavi discusses climate change, global warming and the monsoon with Professor Narasimha. The second segment of a two-part feature:






Formation of hailstones

When moist air in clouds keeps rising it will freeze. Will that produce hailstones or snowflakes?

So there are two phase changes that could occur.
From vapour to liquid and liquid to solid.
Each time the phase changes occur, the flow properties in the cloud undergo a change.
Why, because you are suddenly putting heat into the flow.
One of the things I have been doing is finding out what happens when you put heat into flow.
You have to make a flow similar to a cloud.




Formation of Snowflakes


So that's what you meant by interaction of thermodynamics and fluid dynamics?

Correct. You have to put the right amount of heat.
So my view now, based on our experiments is, you can make a cloud flow and a live cloud plume in any fluid you like -- Water, oil, mercury -- but subject to one condition: The amount of heat you put in must bear a certain ratio to the energy of the flow in the fluid.
You do that you will get something very similar to what happens in the sky.
A cloud is a special kind of plume. That is our conclusion.
First of all, we say cloud is a transient plume. It has a finite lifespan. I have been doing a lot of experiments in the lab and on the computer and it is a lot of fun.


It comes as a surprise to many people that these things that we see every day, which we admire and love are not understood.



IMAGE: Vehicles wade through water-logged streets after heavy rainfall in Mumbai. Photograph: PTI Photo



Many people have given up saying it is chaos, butterfly effect, there are too many unknowns etc...

You are quite right. The scientific study of clouds started around the 1960s. Very simple experiments were made.
Unfortunately, by the 1970s, it was realised that those simple experiments were not behaving like clouds at all. So the attempt to make cloud flows in the lab sort of declined.
But you can say we picked it up where they had stopped. In the 1980s, I started an experiment in IISc (the Indian Institute of Science, Bengaluru) and that experiment turned out to be very revealing.
From then on I have been doing clouds in some form or other. We are getting closer and closer to a cloud flow and you can reproduce a wide variety of cloud types in our water tank.
At that stage a lot of people started taking notice. Now I am interested in getting the details right on the computer.
In the lab, it is difficult to reproduce all conditions, including water vapour, condensation and so on because the setup in the lab cannot be very big.
But, in the computer, I have from one point of view more freedom provided I have access to super computer time. Right now we are making cloud simulations on the computer.




IMAGE: Army personnel rescue residents from a flooded area in Chennai, December 15, 2015. Photograph: PTI Photo

Which computer are you using?

That is my big problem. The CSIR Fourth Paradigm Institute (CSIR-4PI) formerly CMMACS (CSIR Centre for Mathematical Modelling & Computer Simulation), Bengaluru acquired a big computer and I made a lot of my computations on that computer.
But that is no longer big enough. IITM (The Indian Institute of Tropical Meteorology) Pune, has a very powerful computer. So, I hope to do some computations there.



IMAGE: A farmer ploughs his rice field in Mathura, June 18, 2008. Photograph: K K Arora/Reuters


I have a stupid question. We had a longstanding traditional Panchanga system, with meteorological applications, and that is what made it important in an agricultural economy.
Now that we have 100 years of reliable data from the Indian Meteorology Department, can we compare the actual weather with Panchanga's predictions and see any correlation and how accurate the predictions were?


If you are talking about rainfall, I think the correlations will be poor.
In the princely state of Mysuru, there was a Panchanga made with Maharaja's patronage called the Ontikoppala Panchanga.
But, we know that Panchanga depends on the longitude, etc. So, there is no way that it can be precise for the whole of Karnataka. However, this doesn't mean they knew nothing.
They did realise that this rain is cyclical. Varsha (a year) is really rain.
Rain is seasonal -- once a year. So the word for year and word for rain is practically the same.
And they had a rough idea about how long it lasted -- 3-4 months.



Photograph: PTI photo



And, in between cycles also, they have Nakshatras associated with different parts of the rainy season...

That is correct. Those are basically empirical and those are correct, but they vary from region to region.
So I did one thing at IISc though not along the lines you are thinking. I said we should talk to the farmers and see what kind of forecasts they are doing.
So we met a few farmers and invited them to Bengaluru at the Institute of Science. They were first of all very pleased that people actually came to them to talk about weather.
I had all the Met department statistics, recorded rainfall, converted into Nakshatras which is available on the CAOS (Centre for Atmospheric and Oceanic Sciences, IISc) Web site.
Then we had a long chat, they all said the predictions we get are not good both from Panchanga and the Met department.



Image: Army personnel rescue an elderly woman in flood affected Chennai, , December 15, 2015. Photograph: PTI Photo



Our Met Department doesn't make detailed predictions. They just say normal, sub-normal, monsoon etc.
Whereas in the US, every region, every TV channel will tell you 12-hour, 24, 48, 72 hours predictions and they are fairly accurate.
So what makes weather prediction complicated in India?


That is a very important question. The dynamics at higher latitudes of Europe and North America are simpler than the dynamics in the tropics.
The tropics are basically more complicated.
It is not that the British and Americans are better at predicting the monsoons than us. They have made big mistakes time and again.
Of course, we keep making mistakes but so have they.
We are more interested in the monsoon than anyone else in the world -- it affects our economy, it is very important in many ways.
So we have to be the foremost experts in the world on the monsoon.
But the best minds in India have not devoted their time to the study of monsoon and they have followed the fashions of the West.
And the West will study what is important to them.
We can say the Indian scientific community as a whole has not looked at our own problems with the same intensity that the Western world has looked at their problems.
What we can say is that with the state of knowledge existing in the world today, not just in India, predicting the monsoon is a tough job.
The Indian response has been to borrow unknown American computer codes and so on, but our experience with them is not any better.
Americans themselves say, 'We can't predict monsoons'.



IMAGE: The El Nino, well known around the world after the recent string of hotter-than-usual years globally, is a variation, irregularly periodic, in winds and sea-surface temperatures over the equatorial Pacific Ocean. Photograph: Reuters



What about El Nino and so on? Was the effect of El Nino on Indian monsoon realised by Indian scientists or they just borrowed it from the West?

That is a very interesting question. El Nino was at that time not known by that name at all.
The physical phenomenon connected with El Nino was first discovered by a British head of the Indian Met department Gilbert Walker, around 1915-1920.
He was a very bright man. When he came here he didn't know any meteorology, but he was fascinated by it.
But after a while he decided that the monsoon was too erratic and he didn't see how you one could understand the dynamics completely.
He said, 'I will try and do statistical predictions' and introduced statistical predictions to the Met department.
Till today, Walker's philosophy -- not precisely his formula but his philosophy -- is what governs predictions in our IMD. It is based on some correlations.
There is now Vasant Gowarikar's model that took many more parameters than Walker's did, but the philosophy was exactly the same.
One of the things that Walker found was that monsoon rainfall in India had a link with what happened in Australia.
In the days of the British Empire he easily got data from many parts of the British Empire.
All the other global networks were not so strong. So he found, for example, what pressure is doing in Port Darwin in Perth has a link with what monsoon is doing in India with a lag.
At that time, this idea was unthinkable. Everybody said monsoons come because of the clouds, what does it have to do with what is happening in Perth.
In fact, people were critical of him. Which is ironic.
Walker didn't live to see that a couple of years after he died, the connection was established by much better measurements. It left no doubt.
That phenomenon is what has grown into El Nino.
The connection that Walker saw between Indian monsoon rainfall and what happened in Northern Australia is one signal of El Nino.
But it is not only Australia.




IMAGE: Snowfall in Tangmarg, Kashmir. Photograph: Danish Ismail/Reuters



So is there a Pacific oscillation just as there is an Atlantic oscillation?

This is called El Sona.
EL Nino is southern oscillation.
There is an Atlantic northern oscillation. More such oscillations have been discovered.
If you have an oscillation, it is slightly more predictable.
Therefore a link with the monsoon can be detected, which is what Walker did.
So you can say it was discovered in India. Not by an Indian, but by a British meteorologist.
Of course there were many people who helped him and all the calculations were made by Indians.




Image: An aerial view of the cyclone-hit village of Ersama in Jagatsingpur district, Odisha, in November 1999.


The village was completely destroyed after the 'super cyclone' hit the state on October 29 that year. Photograph: Reuters

The meteorological satellites launched by ISRO to study ocean surface temperatures etc, have they helped in any way?

Yes, in a big way. To give you a striking example, look at our cyclone predictions now.
Recently, there was this big cyclone over Odisha. The Indian met department got it right because they had overall satellite data.
Therefore, the cyclone was tracked right from the time it was born. And if you remember in the previous super cyclone (in 1999) thousands of people were killed.
This time it was more like 10 or 20 people.
In fact our met department had also predicted the cloud burst that happened in Kedarnath, Uttarakhand. But no government department took it seriously. And it led to a major disaster.
So when this cyclone came to Odisha no bureaucrat and politician wanted to get caught unprepared once again. So they took it seriously and very few people died in Odisha.
So that kind of relatively short-term prediction we are getting better at.
Doppler radar too helps a great deal in short-term prediction whereas our satellites help a great deal over the life cycle of a cyclone.
They also help in studying climate change. Now we can track changes that have occurred over the past 20, 30 years.



IMAGE: A flooded street in Chennai, December 2015. Photograph: Anindito Mukherjee/Reuters



Has computer modelling helped?

Computer modelling has helped, but not as much as one would have liked.



IMAGE: The Srinagar-Jammu national highway shut by snowfall last year. Photograph: Umar Ganie for Rediff.com

Is computer modelling easier in the higher latitudes?

By and large it is easier. The clouds are what stump us in the computer models of the tropics.
Northern latitudes do not have this kind of cumulus clouds. They are largely static clouds, spread clouds.
So that is why clouds are very important to India and that is how my interest in clouds started.


Production: Ashish Narsale/Rediff.com


'We are more interested in the monsoon than anyone else in the world'
 

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DELHI NEWS
Delhi weather: IMD predicts light rain today and tomorrow
The minimum temperature on Friday is likely to be 26 degrees Celsius while the maximum temperature is predicted to hover around 37 degrees Celsius
By HT Correspondent

PUBLISHED ON JUL 16, 2021 08:34 AM IST


Delhi is likely to see light rain on Friday as per the India Meteorological Department (IMD) forecast. Light rain or drizzle has also been predicted for Saturday.

The minimum temperature on Friday is likely to be 26 degrees Celsius while the maximum temperature is predicted to hover around 37 degrees Celsius. The minimum temperature on Thursday was 23.4 degrees Celsius and the maximum temperature was 36.6 degrees Celsius.

Delhi’s air quality was in the satisfactory category on Friday morning. Data from Central Pollution Control Board showed that the hourly air quality index (AQI) at 7am stood at 91. On Thursday, the average 24-hour AQI stood at 83 in the satisfactory category. An AQI between zero and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, and 401 and 500 severe.

On Thursday, the union ministry of earth science’s air quality monitoring centre, System of Air Quality and Weather Forecasting and Research (Safar) said, “The overall air quality is in the satisfactory category as forecasted. Surface winds are high and the southwest monsoon has advanced into Delhi. Thundershowers observed over Delhi. Increased rainfall activity is likely to influence AQI positively. Widespread rainfall is likely during the next few days. Satisfactory to good AQI is forecasted for the next three days.”


Delhi weather: IMD predicts light rain today and tomorrow
 

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Clear Day In Delhi Today, Heavy Rainfall Likely Tomorrow: Weather Department

Delhi Weather Today: The weather department has predicted partly cloudy sky with light rain or thundershowers later in the day, while the maximum temperature is expected to hover around 37 degrees Celsius.

DelhiPress Trust of IndiaUpdated: July 17, 2021 1:41 pm IST


Clear Day In Delhi Today, Heavy Rainfall Likely Tomorrow: Weather Department


The weather department predicted heavy rainfall at isolated places in Delhi tomorrow.

New Delhi:
People in Delhi woke up to a clear morning today with the minimum temperature settling at 28.2 degrees Celsius, a degree above the season's normal.
The India Meteorological Department or IMD has, however, predicted heavy rainfall at isolated places in the national capital tomorrow.
"The minimum temperature recorded at the Safdarjung Observatory, considered the official reading of the city, was 28.2 degrees Celsius, and the relative humidity at 8:30 am was recorded at 75 per cent," it said.
The weather department has predicted partly cloudy sky with light rain or thundershowers later in the day, while the maximum temperature is expected to hover around 37 degrees Celsius.

Delhi had received the first rain of the monsoon season on Tuesday, 16 days after the usual date of June 27.


On Friday, the minimum temperature in the national capital was recorded at 27 degrees Celsius, while the maximum settled at 37.8 degrees Celsius, three notches above the season's normal.


Clear Day In Delhi Today, Heavy Rainfall Likely Tomorrow: Weather Department
 

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No Chance of Rains in Sunday Morning :
All Clear !


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Chance of Rain is in Afternoon 1pm onwards :


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Rain is possible is in evening also :


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Sunday, 18 July 2021
Delhi
 
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