Lok Sabha Question No. 3353 (UNSTARRED), answered on 2022-03-23
Subject: Inaccurate Weather Forecast by IMD
Ministry: EARTH SCIENCES
Asked by: Chandeshwar Prasad

## GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES LOKSABHA

## UNSTARRED QUESTION NO. 3353 TO BE ANSWERED ON WEDNESDAY, 23 RD MARC ,20

## INACCURATE WEATHER FORECAST

## 3353. SHRI CHANDESHWAR PRASAD:

Will the Minister of EARTH SCIENCES be pleased to state:

- (a) whether monsoon was not as per the forecast made by th Indi n Meteorological Department (IMD) in the country;
- (b) if so, the details thereof;
- (c) the reasons as to why weather forecast by the IMD often go wrong; and
- (d) the details of the corrective steps taken in this regard?

## ANSWER

## THE MINISTER OF STATE (INDEPENDENT CHARqE) F R MINISTRY OF SCIENCE AND TECHNOLOGY! AND EARTH SCIENCES (DR. JITENDRA SINGH)

- (a)-(b) No, Sir. Progress of the monsoon in the country was very wel predfcted by the India Meteorological Department (IMD). In this regard Press releases were r gularly issued by IMD.

Pointwise details follow:

- Southwest Monsoon Set in over South Andaman Sea and over s, me parts of north Andaman Sea on 21st May 2021. Monsoon onset over KeralJ occuted 3rd June 2021. i.
- Southwest Monsoon continued it's advance over the Juntry I till 13th June in association with favourable atmospheric circulation and a jbW Plrssure system over Bay of Bengal after the onset of monsoon over Kerala on 3r June. ii.
- By 13th June, it covered most parts of the country except north I est India On 13th June, Numerical weather prediction (NWP) models s ggest!d the favourable conditions with moist lower level easterly winds reaching fO noI1hwest India which may help further advance of monsoon into most parts Madhya fradesh; remaining parts of Uttar Pradesh; Delhi; Haryana and Punjab during su~sequent 48 hours. Accordingly, a press release was. issued by 13th June indicating likely advance of monsoon into Delhi by 15th June. l iii.
- On 14th June, however, weather analysis based on sa ellite and NWP model consensus indicated approach of a trough in mid- latitude ~I esterl winds, leading to weakening of easterly winds over northwest India. Due to adver e influence of this mid-latitude westerly winds, further advance of monsooq into remaining parts of northwest India including Delhi was not expected. ACC<i>rding~~, IMD issued an updated press release on 14th June indicating that furthbr ad ance of southwest Monsoon into remaining parts of northwest India includin~Delhi would be slow and delayed". However, this development of interaction wit west rlies could not be anticipated by the weather prediction models well in advanc . iv.

## 2

- v. On 16th June, another press release was immediately is~ed indicating delay in monsoon advance into Delhi and slow progress into some parts Jf northwest India. ~~Ce~rdinglY monsoon advanced into some more parts .: est India by 19th
2. Since 20 June, there was no further advance of monsoon du . to weak/break monsoon conditions. Regular press releases were issued and updated to m1ediafrom time to time on 22, 24, 26 and 30 June and 1 July indicating such detays in monsoon advance into remaining parts of northwest India including Delhi and weaklbreak monsoon conditions over the country. The delay in monsoon advance Iwas~ainly due to (i) no formation of low pressure area over Bay of Bengal, (ii) 110 prefence of monsoon trough at mean sea level near to Delhi, (iii) 5-6 Western disturbanfes moved west to east across North India which dominated over the monsoon tterIies, vi.
3. On 5th July, updated press release on Status of monsoon ~as iss ed indicating that monsoon would advance into remaining parts of West Uttar Prades ,some more parts of Punjab, Haryana and Rajasthan and Delhi around 10th JUlt, vu,
4. After 8th July, easterly winds at lower levels were established alo g the foothills and from 9th July onwards easterly winds were established orer pl. nes of Northwest India. These moisture laden easterly winds led to increase f' cloutliness and relative humidity. It also led to revival of monsoon over the region and opcurrence of fairly widespread/widespread rainfall activity over east Rajastha , HP, !Uttarakhand, J&K and scattered rainfall over Punjab and west Rajasthan. H?WeVer, it did not cause significant rainfall activity over Delhi even though, there )Vasramfall activity over neighbouring places around Delhi. Such type of failure ~y nterical models in prediction of monsoon advance over Delhi is rare and unco l mmo . It is needless to mention that IMD predicted well with high accuracy about the a vance of monsoon over Delhi in the recent past years and also the advance of mon~oon over different parts of the country during the monsoon -2021 accurately abOi four to five days ahead. IMD monitored the situation continuously and provided the regular updates on advance of monsoon into remaining parts of northwest India inclu .ng Delhi. viii.
5. The southwest monsoon further advanced into remaini g pa s of the country and thus the Southwest Monsoon covered entire country (In 13t July, against the normal date of08th July (Figure). IX.
6. Seasonal forecasts were issued on 1st June to the four broad geo!faphical regions of India viz. Northwest India, Central India, Northeast Indid and South Peninsulathe I I season as a whole were normal (92-108% of LPA), above norm~ (>106% of LPA), below normal «95% of LPA) & normal (93-107% of LPA), resp .ctively. The newly introduced seasonal rainfall over Monsoon Core Zone (M~Z) w s forecasted to be above normal (>106% of LPA). And the actual observe1 rain 11over Northwest India, Central India, Northeast India, South Peninsula and Monsoon Core Zone were 96%, 104%, 88%, 111% and 107 % of the Long Period Ave age ( I.PA),respectively. x.
7. (c) Does not arise.
8. IMD follows a seamless forecasting strategy. The long-range orecas±s (for the whole season) issued are being followed with extended range forecast is~ued 0 every Thursday with a validity period of four weeks. To follow up the extended r~ge fo ecast, !MD issues short to medium range forecast and warnings at 36 meteorological sub-di isions levels daily four times by the National Weather Forecasting Centre (NWFC),I New Delhi valid up to next five days with an outlook for subsequent two days. The short t~ med urn range forecast and warning at district and station level are issued by state lev. el Mete rological Centres (MCs)/Regional Meteorological Centres (RMCs) with a validity 0 next five days and are updated twice a day. The. short to medium range forecast is folio' ed by very short range forecast of severe weather up to three hours (nowcast) for all the distri10,ts and 1085 cities and towns. These nowcasts are updated every three hours. (d)

While issuing the warning suitable colour code is used to bring ou the i pact of the severe weather expected and to signal the Disaster Management about t e cou~se of action to be taken with respect to impending disaster weather event. Green dolour orresponds to no warning hence no action is needed, yellow colour corresponds to be watchful and get updated information, orange colour to be alert and be prepared to take ction whereas red colour signals to take action.

IMD is issuing Impact Based Forecast (IBF) which give details of hat t e weather will do rather than what the weather will be. It contains the details of i pacts xpected from the severe weather elements and guidelines to general public about do'~and on'ts while getting exposed to severe weather. These guidelines are finalised in col abora ion with National Disaster Management Authority (NDMA) and is already imple ente successfully for cyclone, heat wave, thunderstorm and heavy rainfall. Work is in progres to implement the same for other severe weather elements.

Annexure

Figure: Advancement of Southwest Monsoon over the country

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