ALL ABOUT CYCLONES: How cyclone track forecasts can change dramatically and how climate change maybe impacting them.

 We have been tracking the storm in the Bay of Bengal for several days now (as we normally do) and have been posting updates in our WhatsApp Group 'Hazard Alerts'.
On 26Nov2024, the forecast from IMD clearly said that the storm would intensify into a CYCLONE

This was changed and on 28Nov and the storm was expected to remain a 'DEEP DEPRESSION' and make landfall on 30Nov2024 as a 'WELL MARKED LOW' (see below)

The forecast was revised the next day and the track showed the storm intensifying into CYCLONE 'FENGAL'on 29Nov2024.
The latest forecast track from IMD of 'FENGAL' together with WARNING no '3' from JTWC is reproduced below.

The tracks from IMD and JTWC seem to coincide.
I am also posting an article from today's Statesman on how climate change maybe impacting cyclones in the Bay of Bengal

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

STH Stormwatch :A tale of two cylones - in May2023.

STH has been tracking and reporting on storms for more than a decade even though now we report largely on a What'sApp group called 'Hazard Alerts'.
In May2023, the very quiet seas in the Bay of Bengal and eastern Pacific suddenly became active and brewed several big storms.
Cyclone 'Mocha' which formed in the Bay of Bengal around 08May2023 and we tracked and reported on the storm extensively:-

As I write Typhoon 'MAWAR' has formed in the eastern Pacific but is likely to weaken from a Super Typhoon to a severe tropical storm as is nears land.

Praful Rao
Kalimpong district
Darjeeling - Sikkim Himalaya
savethehills@gmail.com
9475033744

STHstormwatch : Forecast tracks of storm in the Bay of Bengal (May2017)

Source

Praful Rao,
Kalimpong dist,
Darjeeling-Sikkim Himalaya

STH Stormwatch : Depression in the Bay of Bengal (21Oct2016)

Updates will be posted as necessary

Update 1 (JTWC IR image of two storms in our region)

Predicted storm track (shown in RED) is an approximation (NOT accurate!).

Update 2 (23Oct2016)

Update 3 (23Oct2016) - IMD predicted track

 
Praful Rao,
Kalimpong,
Dist Darjeeling

Onset of SouthWest Monsoon 2016.

 Forecast of the Onset Date of Southwest Monsoon - 2016 over Kerala (Excerpts)

1. Background
The onset of southwest monsoon over Kerala signals the arrival of monsoon over the Indian subcontinent and represents beginning of rainy season over the region. The normal monsoon onset over Kerala is 01 June. Since 2005, India Meteorological Department (IMD) has been issuing operational forecasts for the date of monsoon onset over Kerala using an indigenously developed statistical model with a model error of ± 4 days.

The forecasts of the monsoon onset issued during the past 11 years (2005-2015) except 2015 were proved to be correct. 

2. Advance of monsoon over the Andaman Sea
The southwest monsoon advances over the Andaman Sea normally around 20th May with a standard deviation of about one week. Strong convective activity has been observed over the equatorial Indian Ocean for the last several days. A well marked low pressure area has formed over the Indian Ocean which will concentrate into a depression and move north-westwards. As a result, conditions are becoming favorable for the onset of southwest monsoon over Nicobar Islands, south Andaman Sea and parts of south Bay of Bengal around 17th May and advancement over the entire Andaman Sea close to its normal date. Past data suggest that there is no association of the date of monsoon advance over the Andaman Sea either with the date of monsoon onset over Kerala or with the seasonal monsoon rainfall over the country.

3. Forecast for the 2016 Monsoon Onset over Kerala
The statistical model forecast suggests that the monsoon onset over Kerala in this year is likely to be slightly delayed. The southwest monsoon is likely to set over Kerala on 7th June with a model error of ± 4 days.

Read full article here

Praful Rao,
Kalimpong,
Darjeeling district

A tale of Two Cyclones : Cyclone 'Chapala' followed by Cyclone 'Megh' in the Arabian sea

Cyclones in the Arabian Sea are comparatively less frequent than those in the Bay of Bengal, and it is rare to see two cyclones in that area, riding bumper to bumper and heading towards the same region (ie the Yemen coast) all within a week!
Cyclone 'Megh' has now formed in the Arabian Sea, hard on the heels of 'Chapala' which dumped almost a decades' worth of rainfall in the deserts of war-torn Yemen a few days ago. The forecast track from JTWC show 'Megh' heading to the same region.

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch : Update on depression on 02Aug2015

Above satellite image has been obtained from Nepal MFD since the IMD website is not working from 05.00am till the time of this report.
The storm has moved over Chatisgarh but the image shows significant clouding over south Bengal. I have verified that it is not raining in Kolkata at least.

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch : Update on depression (Bulletin 27)

Excerpt from IMD Bulletin 27 (Bay of Bengal) issued at 2000h (IST) on 01Aug2015
'The depression over Bangladesh moved west northwestwards and lay centred at 1730 hrs IST of today, the 01 August 2015 over Gangetic West Bengal and adjoining Bangladesh near latitude 23.80N and longitude 88.40E, about 30 km south southeast of Berhampore (West Bengal). It would move west northwestwards and weaken into a well marked low pressure area gradually.'

Comment by Praful Rao

I wish IMD would give more frequent weather bulletins and analysis especially when we are exposed to severe and extreme weather. It is pathetic that position of the storm has been updated after almost 9hrs (Bulletin 26  and information on the storm position was issued at 11.30am this morning after which there was no update till now).

The state of IMD AWS/ARG stations are no less dismal with most of the AWS/ARG stations either non-functional or giving erratic data.

Thank goodness their satellite imagery is different and works almost flawlessly well.

Praful Rao

Kalimpong,

Dist Darjeeling

STH Stormwatch : Update on depresssion from IMD (1130h, 01Aug2015)

Excerpt from IMD Bulletin No 26 (Bay of Bengal) Issued at 1130h (IST) on 01Aug2015 

'The depression over Bangladesh remained practically stationary during past 3 hours and lay centred at 0830 hrs IST of today, the 01 August 2015 over Bangladesh near latitude 23.20N and longitude 89.20E, close to Jessore (Bangladesh). It would move west northwestwards and further weaken into a well marked low pressure area gradually.'

Rainfall in the past 24hrs 
Kolkata : 133.6mm
DumDum : 131.4mm
Gangtok : 2.5mm
Kalimpong : 2.2mm
 
Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch (Updated tracks of depression in Bay of Bengal) from JTWC and position of depression (IMD) : 29/30Jul2015

The above updates are from here.

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch : Update on DEEP depression in Bay of Bengal (29Jul2015)

Placed above are images from JTWC (Google Earth) and the latest IR2 image from IMD of the deep depression in the Bay of Bengal.

Excerpt from IMD (0900h, 29July2015)
'The depression over northeast Bay of Bengal and adjoining coastal areas of Bangladesh & West Bengal moved southeastwards, concentrated into a deep depression and lay centred at 0530 hours IST of today, the 29th July, 2015 over north east Bay of Bengal and adjoining areas of Bangladesh near Lat. 21.0 ° N and Long. 91.0 °E, 160 km south­ southwest of Chittagong (Bangladesh). The system would move nearly northward and cross Bangladesh Coast on 30th forenoon between Long. 90.5 °E and 91.5 °E.'

Praful Rao,
Kalimpong,
Dist Darjeeling

NB: Italics are mine.

STH stormwatch : First depression of 2015 in the Bay of Bengal

'The depression over northwest & adjoining westcentral Bay of Bengal off north Andhra Pradesh­south Odisha coast moved northwestwards during past 3 hours and lay centred at 1730 hours IST of today, near Lat. 18.5°N and Long.85.5°E, about 150 km south of Puri.
The system would move northwestwards and cross Odisha coast between Gopalpur and Puri by tomorrow forenoon.'
- IMetD

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch (07Nov2014 update) : Track/winds of deep depression in Bay of Bengal

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Stormwatch (05Nov2014 update): The low pressure intensifies into a depression

As per JTWC, 'the potential for the development of a significant tropical cyclone within the next 24hr is upgraded to medium'

Praful Rao,
Kalimpong,
Dist Darjeeling

STH stormwatch (23May2014) : POOF! and the storm disappears!!!

The depression which was predicted to move northwestwards towards Bangladesh both by the JTWC and IMetD yesterday, seemed to have a mind of its own today and curved southwest wards and quite suddenly weakened into a well marked low and as such has become insignificant.
It's amazing that all the science and technology in the world cannot quite  predict or understand the behavior of these storms as they wax and wane in the ocean.

Praful Rao,
Kalimpong,
Dist Darjeeling

STH stormwatch (22May2014 update) : JTWC changes predicted track

For further details go here
Whereas on 21May2014, the depression was seen moving east towards MyanMar, on 22May2014, the projected track shows the storm moving northwest towards Bangladesh and could well affect W. Bengal as well.
This forecast seems in keeping with the meteorological analysis by IMetD (22May2014) in its ALL INDIA WEATHER BULLETIN (Night), which states :-
'The depression over east central Bay of Bengal moved north-northwestwards and lay centered at 1730 hours IST of today, near lat.17.5°N and long. 92.0E, about 650 km north-northwest of Port Blair. It would move north-northwestwards during next 48 hours'

Praful Rao,
Kalimpong,
Dist Darjeeling

STH stormwatch (21May2014) : TRMM Sees Stormy Bay Of Bengal + Updates

The TRMM website is one of the many that STH uses while keeping a track of the storms that brew up in the Bay of Bengal.
Placed below is an image juxtaposing the latest image of the storm taken from IMD with that on the TRMM website.

* Update at 0830h IST, 21May2014
The low pressure area over eastcentral Bay of Bengal & neighbourhood concentrated into depression at 0830 hours IST of today, the 21st May 2014 near latitude 15.5°N and longitude 90.5°E over eastcentral Bay of Bengal, about 490 km north­northwest of Port Blair.
It may intensify further into a deep depression during next 24 hours. It would move near northwards for some time andthen north­northeastwards towards Myanmar & adjoining Bangladesh coast during next 48 h

For anyone interested in details see here

Praful Rao,
Kalimpong,
Dist Darjeeling

STH stormwatch updates (19/20Nov2013) : Depression pressure intensifies in Bay of Bengal

All India Weather Bulletin (Morning)
The low pressure area over southeast and adjoining central Bay of Bengal has intensified into a depression over westcentral Bay of Bengal and lay centred at 0530 hours IST of today near Lat.14.5° N and Long. 86.5 °E , about 700km east-­north east of Chennai, 600 km east-­southeast of Machilipatnam and 500 km south­east of Vishakhapatnam.
The depression would intensify into a deep depression and move northwestward towards Andhra Pradesh coast during the next 72h

Update of 20Nov2013(0530h IST)
The above depression has intensified into a deep depression

Praful Rao,
Kalimpong,
Dist Darjeeling

STH Storm watch : 21Oct2013 - Low pressure reported over central parts of south Bay of Bengal

We are now at the end of the cyclone season in the Bay of Bengal with winter right around the corner.2013 saw cyclone 'Mahasen' greeting the monsoon season and lets hope 'Phailin' was farewell to the rain bearing winds which are now on their way out of the sub-continent. Having said this though IMetD reported another low pressure over central parts of South Bay of Bengal on 20Oct2013, excerpts from Bulletin are below :

" The low pressure area over central parts of south Bay of Bengal and neighbourhood
persists."
" Prediction of meteorological condition :
The low pressure area over central parts of south Bay of Bengal would move northwestwards and would intensify into a well marked low pressure area during next 24 hours."

Mid-Day Update (21Oct2013) 
"The well marked low pressure area over southwest Bay of Bengal and neighbourhood may concentrate into a depression during next 24hrs."

Update on 23Oct2013

A well marked low pressure has formed, likely movement - west northwestwards

(Source : IMetD)
Rohan Rao,
Kalimpong,
Dist-Darjeeling,
Email: rohan.rao1313@gmail.com

STH storm watch (30May2013): Depression update

Source

Praful Rao,
Kalimpong