Weather Forecast & Current Climate Conditions

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ramana
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Re: Weather Forecast & Current Climate Conditions

Postby ramana » 15 Jan 2016 00:36

Some expert from National Weather Service in DC, Steve Anderson(?) came on radio and said the El Nino is petering out. Its like any other normal winter rainfall in California. Only thing is it will extend beyond April into May.

This El Nino wont reduce the 4 year drought. It might be less severe than past 4 years. IOW the amount of rainfall while average will not pull California out of the drought.

Need to think what he means about the El Nino weather pattern.

Same time they were reporting South Africa this year had 1/3 less rainfall than average. This is the Indian Ocean area.

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Re: Weather Forecast & Current Climate Conditions

Postby ramana » 23 Feb 2016 03:13

Bade The weather experts are saying the El Nino this year has completed.

Doesn't mean there will be no more rains.
The seas are still 0.5 degree warmer.

The guy said something like its like 1957(?) and not 1997(?)
We had floods in the latter year.

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Re: Weather Forecast & Current Climate Conditions

Postby Bade » 23 Feb 2016 16:21


Bade
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Re: Weather Forecast & Current Climate Conditions

Postby Bade » 23 Feb 2016 20:06

https://www.washingtonpost.com/news/wor ... -or-india/
Image

The himalayas which help us in containing the monsoons and making the northern plains wet, perhaps is also acting as a container for airborne pollution of particulates. Peninsular India get washed and scrubbed with frequent circulation from the oceans.

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Re: Weather Forecast & Current Climate Conditions

Postby Amber G. » 24 Feb 2016 12:31


ramana
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Re: Weather Forecast & Current Climate Conditions

Postby ramana » 15 Apr 2016 03:06

Indian Monsoon: What to make of the IMD forecast?


The Hindu decided to find out whether these forecasts have worked in the past. Answer (based on 10 years of forecast data): not very accurately

Following the India Meteorological Department’s forecast of an ‘above normal’ monsoon of 106 per cent of the Long Period Average (LPA) on Tuesday, The Hindu decided to find out whether these forecasts have worked in the past. Answer (based on 10 years of forecast data): not very accurately. Still, as the IMD puts it, they convey useful information and forecasting itself will only get better with better tools. Here’s a Q&A on the things to know about monsoon forecasting:

To start with, what is LPA?

Long Period Average (or LPA) is defined as the average of the rainfall received during a fifty year period between 1951 and 2000, which comes to about 89 cm.

How does IMD give out its forecasts?

IMD classifies its rainfall forecast into five ‘ranges’ based on the percentage value of its LPA: deficient (less than 90), below normal (90-96), normal (96-104), above normal (104-110) and excess (more than 110).

How good have these forecasts been in the past?

An analysis of ten years’ forecast data shows that the IMD’s April forecast got the ‘rainfall range’ wrong 70 per cent of the times. The June-July forecast, considered a revised and a more accurate monsoon forecast got the ‘rainfall range’ wrong 60 per cent of the times. (See charts). In other words, if the IMD said that rainfall would be ‘below normal’, it could turn out to be ‘deficient’. There have also been a few years when despite a prediction of below-normal rainfall, rainfall was above normal, with many regions experiencing devastating floods.

June forecast against actual rainfall (2006-2015)


In deciding whether the IMD’s rainfall range was right or not, The Hindu factored in the margin of error that the IMD attaches to its prediction statistics. Usually the April forecast comes with a margin of error of ± 5% and the June forecast with a margin of error of ± 4%. Even accounting for this error margin, The Hindu found the actual rainfall range deviated from predicted levels.

M.S. Swaminathan, head of the M.S Swaminathan Research Foundation and a keen watcher of monsoon forecasts as they matter to the farmers, said that in most cases when the IMD predicted a normal monsoon, it would so happen that rain that is supposed to fall in a month, falls in a matter of two days, with many places even flooding. “IMD forecasts do not provide much insight into the spatial distribution patterns of the rain and that is where they need to improve their services,” he said.

What purpose do they serve, then?

We asked the IMD to explain how important these rainfall ranges were, and how it affected the extent of monsoon rainfall to be received in a given year. Laxman Singh Rathore, Director General of Meteorology at the IMD, told The Hindu that the intention of the agency in giving out these predictions was only to convey the direction in which the weather pattern is likely to develop and not to exactly predict what would happen. “If we say that the monsoon is below normal and it turns out to be deficient, then what that means is that we got the tendency correct though the magnitude may not be right,” he said.

And are there reasons to believe that these forecasts will get better?

D.S. Pai, Director, Long Range Forecast at IMD in Pune, told The Hindu that five predictors were used for creating models for monsoon forecast, the methodology known as ensemble statistical forecasting system. By way of multiple regressions, the five predictors - Sea Surface Temperature (SST) Gradient between North Atlantic and North Pacific, Equatorial South Indian Ocean SST, East Asia Mean Sea Level Pressure, Northwest Europe Land Surface Air Temperature and Equatorial Pacific Warm Water Volume - were projected to create 62 models using various permutations and combinations of these, and the average of the forecast emerging from the best of these models were taken to arrive at the final figure. Mr. Pai said that this method was introduced in 2007, and since then there have been considerable improvements in predicting the drift of the weather pattern. Even if that was the case in 2009, the Long Range Forecast in June predicted 93% rainfall (below normal) but only 77% rainfall was actually received across India by the end of the year- a huge margin of difference.

Meteorologists agree that with a statistical model, accuracy of predictions is hard to come by. Mr. Rathore admitted that the agency’s skill in the statistical domain was rather poor and more refinement is desirable. He pointed to steps being taken in this direction with efforts to switch to a dynamic model of prediction, in which the ocean and atmospheric temperature levels were coupled to create a single model. The supercomputer Aditya was being tested for this dynamic model of forecasting in the IMD’s Pune centre and “we would be able to switch to this method of forecasting in a few years from now,” Mr. Rathore said.



Bade your views?

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Re: Weather Forecast & Current Climate Conditions

Postby Bade » 15 Apr 2016 08:59

I cannot claim to be a weather prediction expert by no means, but long range forecasts done by any other agency in the world, does not have the granularity in space or time that a 5-day advance weather forecast has. Long range forecasts use input parameters which have scales so large in time or space (the 5 parameters mentioned above), that it would be fool-hardy to think they can accurately predict what is going to happen say in Rayalseema district in 3 months time. All it does is predict a general trend. Like the El Nino driven storms in California which were predicted to happen under such favorable conditions. Exact locations were never predicted as far as I know.

One just cannot get better granularity output when one begins with coarser parameters, which are easy to see or formulate these days with satellite imagery etc. or even if modeling with measured input parameters on the ground.

More granularity in input is harder as it will look more noisy, which means no clear structures to infer anything useful.

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Re: Weather Forecast & Current Climate Conditions

Postby ramana » 15 Apr 2016 10:24

So what's the dynamic model the IMD is talking about?

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Re: Weather Forecast & Current Climate Conditions

Postby Bade » 15 Apr 2016 20:32

I think they mean coupled ocean-atmosphere model by the term dynamic.

Wiki has a nice explanation..
https://en.wikipedia.org/wiki/General_Circulation_Model

Specifically,
The global climate models used for climate projections are similar in structure to (and often share computer code with) numerical models for weather prediction, but are nonetheless logically distinct.

Most weather forecasting is done on the basis of interpreting numerical model results. Since forecasts are short—typically a few days or a week—such models do not usually contain an ocean model but rely on imposed SSTs. They also require accurate initial conditions to begin the forecast—typically these are taken from the output of a previous forecast, blended with observations. Predictions must require only a few hours; but because they only cover a one week the models can be run at higher resolution than in climate mode.

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Re: Weather Forecast & Current Climate Conditions

Postby Bade » 15 Apr 2016 20:36

http://www.wmo.int/pages/themes/climate ... models.php

This has a nice explanation on coupled models...

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Re: Weather Forecast & Current Climate Conditions

Postby jayasimha » 06 Jun 2017 18:28

http://pib.nic.in/newsite/PrintRelease. ... lid=164439

Press Information Bureau
Government of India
Ministry of Earth Science
06-June-2017 16:16 IST
Long Range Forecast Update for the Southwest Monsoon Seasonal Rainfall 2017

Monsoon Seasonal Rainfall likely to be 98% of the Long Period Average

The second stage forecast of Southwest monsoon seasonal rainfall was issued by Indian Meteorological Department(IMD) in New Delhi today. IMD has forecast that quantitatively, the monsoon seasonal rainfall for the country as a whole is likely to be 98% of the Long Period Average (LPA) with an error of ± 4%.

HIGHLIGHTS

Ø Rainfall over the country as a whole for the 2017 southwest monsoon season (June to September) is most likely to be NORMAL (96% to 104% of long period average (LPA)).
Ø Quantitatively, monsoon season rainfall for the country as a whole is likely to be 98% of the LPA with a model error of ±4%.
Ø Region wise, the season rainfall is likely to be 96% of LPA over North-West India, 100% of LPA over Central India, 99% of LPA over South Peninsula and 96% of LPA over North-East India all with a model error of ± 8 %.
Ø The monthly rainfall over the country as whole is likely to be 96% of its LPA during July and 99% of LPA during August both with a model error of ± 9 %.

India Meteorological Department (IMD) had issued the first stage operational long range forecasts for the southwest monsoon season (June-September) 2017 rainfall over the country as a whole on 18th April. In addition to the update of its April assessment, forecasts for the monthly rainfall for July and August 2017 over the country as a whole, and seasonal rainfall forecast for the 4 broad geographical regions of India (NW India, NE India, Central India and South Peninsula) are also presented.

The forecast update for the southwest monsoon season (June-September) rainfall over the country as a whole was prepared using a 6-parameter Statistical Ensemble Forecasting System (SEFS). The 6 predictors used are: NE Pacific to NW Atlantic Sea Surface Temperature (SST) Anomaly Gradient (December + January), Southeast equatorial Indian Ocean SST (February), East Asia Mean Sea Level Pressure (February + March), Central Pacific (Nino 3.4) SST tendency (December to February to March to May), North Atlantic Mean Sea Level Pressure (May) and Northcentral Pacific 850 zonal wind gradient (May).

Dynamical forecast update generated in real time based on the Monsoon Mission Coupled Forecasting System (MMCFS) is also presented. The latest version of the MMCFS (currently operated horizontal resolution of 38km (T382)) is now implemented for operational use for rigorous performance evaluation on an experimental model in parallel with the SEFS at the Office of Climate Research and Services, IMD, Pune upon its transfer from Indian Institute of Tropical Meteorology, Pune.

Sea Surface Temperature Conditions in the Pacific & Indian Oceans

Since mid-March 2017, warm ENSO neutral conditions are prevailing over the tropical Pacific. The atmospheric conditions over the Pacific also reflect neutral ENSO conditions. The latest forecast from MMCFS indicates neutral ENSO conditions are likely till end of this year. This is in line with the forecasts from some of the global climate centers. However, outlook from other global climate centers also indicates about 60% probability of development of weak El Niño conditions during the second half of this year (2017).

In addition to the ENSO conditions over Pacific, other factors such as the Indian Ocean SSTs have also influence on monsoon rainfall. At present, neutral Indian Ocean Dipole (IOD) conditions are prevailing over Indian Ocean. The latest forecast from the MMCFS indicates weak positive IOD conditions are likely to develop during the monsoon season.

The second Stage Forecasts of Southwest Monsoon Seasonal Rainfall for 2017

i) Monsoon Mission Coupled Forecasting System (MMCFS)
The latest experimental forecast based on the MMCFS suggest that the monsoon rainfall during the 2017 monsoon season (June to September) averaged over the country as a whole is likely to be 100% ± 5% of LPA.

ii) Seasonal (June-September) Rainfall over the country as a whole

Quantitatively, the season rainfall for the country as a whole is likely to be 98% of the long period average (LPA) with a model error of ±4%. The LPA rainfall over the country as a whole for the period 1951-2000 is 89 cm.

The 5 category probability forecasts for the Season (June to September) rainfall over the country as a whole is given below.

Category ▌ Rainfall Range ▌ Forecast Probability▌ Climatological probability
··········· ▌····(% of LPA)····▌········(%)·············▌··(%)
······························································································
Deficient▌   < 90                 ▌7 ▌16
Below Normal ▌90 - 96 ▌28 ▌17
Normal ▌96 -104 ▌50 ▌33
Above Normal ▌104 -110 ▌13 ▌16
Excess ▌> 110 ▌ 2 ▌17
································································································

It is to mention that region wise forecast assessment based on MMCFS was nearly in line with the forecast from the statistical models.

iii) Season (June-September) Rainfall over Broad Geographical Regions
The season rainfall is likely to be 96% of LPA over North-West India, 100% of LPA over Central India, 99% of LPA over South Peninsula, and 96% of LPA over North-East India all with a model error of ± 8 %.

iv) Monthly (July & August) Rainfall over the country as a whole
The rainfall over the country as a whole is likely to be 96% of its LPA during July and 99% of LPA during August both with a model error of ± 9 %.
--------

RDS/nb

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Re: Weather Forecast & Current Climate Conditions

Postby Sridhar K » 23 Jul 2017 11:59

An amateur blogger on weather has been prett spot on with the predictions on rain so much so that he is the defacto weather channel for most in Chennai.

He is predicting a huge deluge in Malwa region over the next few days.
https://m.facebook.com/story.php?story_fbid=2090097811217492&id=1471936623033617

100 year event awaiting to happen along South Rajasthan / parts of Gujarat from today till Tuesday - Hope the Govts, there are ready with all precautions. They should announce holiday for next 2-3 days in that region including offices.
===============================
One hell of a rains is expected to happen along south Rajasthan-Gujarat region. Some parts of West Madhya Pradesh will also get pounded. Models are damn consistent. I feel the rains predicted by models is two times of what we got in December 1st (Chennai) and that too in desert areas. This is mind blowing rains. This happens when monsoon low gets locked in Gujarat and cannot move anywhere else. It has to dump all the rains there with constant supply of fuel (moisture) as the low lies at one end of monsoon axis.

Lets see the river basins model in the areas, they pick up huge inflows subsequent to the rains. There is good probability that this is going to be an 50-100 year event. So people near the river banks, please evacuate.

See the images, u can get the idea of the rains expected to happen. This is just an estimate, reality may be much higher.

Tamil Nadu Veppa Salanam rains in last week
==============
Tamil Nadu Convective Rains will pick up from 25th July. The last week will be filled with lots of thunderstorms. Chennai will benefit one or two days for sure.

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Re: Weather Forecast & Current Climate Conditions

Postby Vips » 14 May 2018 06:15

IMD to add 30 Doppler radars in country.

The India Meteorological Department (IMD) will add 30 Doppler radars in the next two-three years across the country, of which several will be in the northeast, a senior IMD official said.

Doppler radars provide precise information about thunderstorms, dust storms, hailstorms, rainfall and wind patterns. With a radius of 250km, they help in issuing nowcasts 2-3 hours prior to severe weather events.

By the next year, Jammu and Kashmir will get four Doppler radars, Uttarakhand and Himachal Pradesh three each, additional director general (ADG) Devendra Pradhan said.

“We plan to add 30 Doppler radars in the next two-three years. The plan is also to have a total number 14 radars in the north east region, including the existing three that are already installed,” Pradhan said.

Right now, the IMD is working on selecting locations in hilly states to install these radars, Pradhan added.

The hilly states of Uttarakhand, Himachal Pradesh and Jammu and Kashmir witness erratic patterns like thunderstorms and heavy rains and snowfall, so do the north eastern states. In 2013, a cloud burst that led to flash floods killed hundreds in Uttarakhand.

The first Doppler radar was installed in Chennai in 2002. Its need became more compelling after the 2005 Mumbai floods. There are currently 27 Doppler radars in the country.

The radar at Jaipur was non-operational during a freak thunderstorm that killed over 120 people in Uttar Pradesh and Rajasthan between 2-3 May.

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Re: Weather Forecast & Current Climate Conditions

Postby ramana » 14 Aug 2018 02:41

There was tweet from SJha that IMD has a new super computer with 12km grid as opposed to 100 km grid and this is state of the art (SOTA) in the world.

If anyone sees links please post here.
TIA, ramana

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Re: Weather Forecast & Current Climate Conditions

Postby jaysimha » 29 Apr 2019 18:22

Image



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Re: Weather Forecast & Current Climate Conditions

Postby jaysimha » 30 Dec 2019 11:52


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Re: Weather Forecast & Current Climate Conditions

Postby jaysimha » 23 May 2020 14:40

Government of India
Ministry of Earth Sciences India Meteorological Department
PRESS RELEASE
Dated: 22-05-2020
Subject: Weather Services from IMD via Mobile App- UMANG


https://mausam.imd.gov.in/backend/assets/press_release_pdf/PRESS_RELEASE_dated_22nd_May_2020_UMANG__mod.pdf

The App is available at following links for download:

1. Web: https://web.umang.gov.in/web/#/
2. Android: https://play.google.com/store/apps/details?id=in.gov.umang.negd.g2c
3. iOS: https://apps.apple.com/in/app/umang/id1236448857

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Re: Weather Forecast & Current Climate Conditions

Postby jaysimha » 25 May 2020 14:25

Image
The Story Of 'India's Cyclone-Man' Whose Efforts Saved Many Lives
https://www.ommcomnews.com/odisha-news/the-story-of-india-s-cyclone-man-whose-efforts-saved-millions-of-lives
Bhubaneswar: Accurate forecast of the natural calamity is a great weapon to contain the damage to life and property, and Dr Mrutunjaya Mohapatra, affectionately called as 'Cyclone-Man' of India is lauded for his accuracy in predicting the cyclones which breed over the Bay of Bengal.


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