Heavy Rains in Kanyakumari and Trivandrum in the morning

May 22, 2020

Heavy Rains in Kanyakumari and Trivandrum in the morning, while going into the day the rains have reduced now, monsoonish conditions will prevail for few more hours. Western TN interior districts will see an increase in Thunderstorms, while Chennai will see another hot day but less than the past 3 days.

Remember the post, a week ago when the cyclone moves up one last pull band will always fall in Kanyakumari and nearby Trivandrum. Rainfall in mm. Kochi too got one good band right over them.

Kanyakumari Rainfall Data

Pechiparai – 123
Perunchani – 89
Puthan dam – 89
Suralacode – 79
Kannimar – 63
Sivalogam – 52
Kuzhithurai – 43
Chittar I – 42
Kaliel – 35

Trivandrum Rainfall Data

Perumkadavila – 135
Trivandrum – 98
Peringimala – 71

more rainfall data will be updated here, as and when available.

North TN coast and nearby interiors – Hot days to continue

Chennai will see another hot day but less than past 3 days and early sea breeze expected, Chennai city will less hot being close to the coast while areas such as Chennai Airport, Porur, Ambattur, Maduravoyoal, Poonamalle all will be hotter as sea breeze will take time to reach there. While it will be hotter in nearby interiors from coast such as Vellore, Kancheepuram, Ranipet, Tiruvallur, Chengalpet, Villupuram, Tiruvannamalai and Kancheepuram. Hot weather will also prevail in Pondy, Cuddalore, Villupuram, and Kallakuruchi belts.

Thunderstorms

With amphan gone, the winds won’t be streamlined now, we can see broken winds in interiors and today western interiors of Tamil Nadu will get good thunderstorms.

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288 mm rainfall fell in 6 hours & was one of the Nature’s balancing act for Core Chennai City

October 30, 2020

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Right from start of the year the Core Chennai City (Old City Areas) was missing all the spells and in South West Monsoon Nungambakkam ended with just 293 mm rainfall in 4 months (lowest rains in last 10 years) while Meenambakkam recorded whopping 597 mm in the same period. You can see twice the amount of rainfall had fallen other parts of Chennai while core areas had not much luck, it happened to miss all the Damal Dumeel Storms in SWM. Infact in all my posts i started to quote Nungambakkam as cursed or desert. This all started to change from October, in North East Monsoon, the places close to sea always has the advantage than the places over inland areas.

The morning of 29th October was a special event for Chennai, the Damal Dumeels brought the memories of November 23, 2015, when dryline-wetline event happened with thunders. Not often you would have seen such thunder in your lifetime, it was very intense ones. The dry air mixed with the moist air and the collusion created so much instability which resulted in such high number of thunders.

The rainfall was split by 6.00 am cut-off time and the rainfall which fell after 6.00 am on 29th October was added into 30th October rainfall. Technically, the rains started at around 3.00 am on 29th October and fell within a space of 6 hours, Mylapore got close to 300 mm and most of which fell in a space of 3 hours. Such was the intensity of the rains, blinding ones at times. The last time a place in Chennai crossed 250 mm rainfall in 24 hours was in November 3rd, 2017, when same Myalpore (DGP Office) recorded whopping 296 mm rainfall which too fell in few hours time.

It was perfect balancing act of Nature for the Core City, indeed and the curse seems to be lifted.

More good spells are due in this 2020 Monsoon. Some spells will be always remembered by me for lifetime for pure uniqueness and my personal favorites over the last 30 years

1996 June 13-14 – 600 mm in 36 hrs (Cyclone)
1996 September 11 – 160 mm in 12 hrs (100 mm fell in an hr – Thunderstorms)
2000 February 24 – 150 mm in 12 hrs (Low Pressure)
2005 October 27 – 420 mm in 24 hrs (Deep Depression)
2005 December 2 – 250 mm in 24 hrs (Baaz Cyclone)
2006 October 27-28 – 300 mm in 48 hrs (Ogni Cyclone)
2008 November 26-28 – 250 mm in 48 hrs (Nisha Cyclone)
2010 May 19 – 180 mm in 15 hrs (Laila Cyclone)
2011 August 24 – 150 mm in 6 hours (Bubble Thunderstorms)
2014 June 10 – 60 mm (Thunderstorms from Sea)
2014 November 18 – 160 mm (onset spell)
2015 April 15 – 125 mm in 3 hours in Tharamani (Thunderstorms from Sea)
2015 November (4 spells) on 8-9, 12-13, 15-16, 23 – 1000 mm for the month
2015 December 1 – 500 mm in 24 hrs in Tambaram (Trough of Low)
2017 November 2 ~ 300 mm in 6 hrs in Mylapore (Low Pressure)
2020 October 29 ~ 300 mm in 6 hrs in Mylapore (UAC – collision of dry & wet air)

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TWM Special – Hippo western bands of Cyclone Mandous to fall over KTCC

December 9, 2022

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1. Where is the cyclone Mandous now and what intensity it is in ?

We can see here that the Cyclone is still over 150 kms away SE of Chennai and is moving in W-NW direction towards North TN coast. The intensity of the Cyclone is around 50 knots and pressure is 998 mb with wind speeds of 90 km/hr.

2. What is the health of the Cyclone Mandous ?

The Sea Surface Temperature (SST) is around 28 C and expected to remain around 28-27 C. While Wind shear which was the reason for the cyclone to weaken from Severe Cyclone to Cyclone is seen reducing from 30-25 knots to 15-20 knots.

4. Why Cyclone Mandous is moving towards Mahabalipuram and not Delta ?

Many people were asking, that cyclone is close to Delta and how it will change track towards South of Chennai. How close does not matter, the ridge position matters, how we travel in our car or bike in the road, the road for the cyclone is the edge of the ridges. Thats why the W-NW movement towards Mahabalipuram and not towards Delta. In other words cyclones are pallam (low) and High pressure are medu when ur inside a pallam, u can traverse only around the ridges of the medu (high pressure).

So the conclusion is that Cyclone Mandous is expected to cross south of Chennai near Mahabs with some + or – some kms on the night of 9th December, 2022 to early morning hours of 10th December.

5. Why only there is cloud on the west side of Cyclone Mandous ?

The east side of the clouds is eroded and exposed due to the wind shear but in the west side where there is convergence buildup, the clouds are gaining back strength. Thats why one side there is clouds and other side there is no clouds.

6. What will be sustained wind speeds and gusts

We follow 3 min average for sustained winds and gusts (small burst of winds at times).

70-80 km/hr – over Mahabalipuram, ECR, Chennai on mid-night to early morning of saturday
60-70 km/hr – Kancheepuram, Tiruvallur district tonight
50 km/hr – Vellore – Ranipet district and partly in Tiruvannamalai district (Tomorrow morning to noon)

For Gusts, add another 10-15 kms to the sustained winds

7. What will be Rainfall and what are the districts ?

Very heavy rainfall is expected to happen around Chengalpet, Chennai, Tiruvallur and Kancheepuram district tonight. Tiruvannamalai and parts of Villupuram too has chance of heavy rains.

The interiors (Ranipet, Vellore, Tiruvannamalai, Tirupattur, Krishnagiri, Chittor and Bangalore) will get rains tomorrow, while the coastal areas will get on 9 night-10th December morning. We will never know which spot among these districts where a big event might occur, which is always associated with Cyclones.

The rains will be intermittent to start with once we are close to the centre, we might see non stop rains for few hours when the centre passes the areas in above districts. Chennai was lucky to get rains a day early compared to other districts.

Once Mandous moves into Arabia sea, the West TN belt like Erode, Kovai and Nilgiris will get pull effect rains. Chennai too might some rains from the pull clouds from other side.

Chennai observed Rainfall from Mandous on 09.12.2022

——–

in mm

Thiruvika Nagar – 82 mm

Anna Nagar West – 79 mm

Kodambakkam – 77 mm

Thiruvottiyur – 75 mm

Teynampet – 74 mm

Ice House – 72 mm

Nandanam – 71 mm

Kolathur – 70 mm

Tondairpet – 69 mm

Madhavaram – 69 mm

Nungambakkam – 68 mm

Raja Annamalaipuram – 68 mm

Meenambakkam – 68 mm

Kathivakkam – 65 mm

Perambur – 63 mm

Aminjikarai – 62 mm

Manali – 62 mm

Puzhal – 61 mm

New Manali Town – 60 mm

Marina (DGP office) – 56

Mugalivakkam – 56 mm

Adyar – 54 mm

Perungudi – 53 mm

MGR Nagar – 51 mm

Aynavaram – 50 mm

Alandur – 50 mm

Palavakkam – 50 mm

Taramani – 50 mm

Vanagaram – 50 mm

8. waves

The areas north of crossing will have the waves very rough. So right from Mahabs to Pulicat Coast dont venture out into seas or even go near the sea shore while crossing. The storm surges might come well into the beaches, so no sight seeing when the cyclone crosses.

9. Maximum sustained winds (3 min average) for Tamil Nadu cyclones in last 30 years

(Min 100 Km/hr at crossing)

1993 – Karaikkal Cyclone – Karaikkal – 167 km/hr
2011 – Cyclone Thane – Cuddalore – 140 km/hr
2018 – Cyclone Gaja – Vedaranyam – 130 km/hr
2000 – Cuddalore Cyclone – Cuddalore – 120 km/hr
1991 – Karaikkal Cyclone – Karaikkal – 120 km/hr
1992 – November Cyclone – Thoothukudi – 120 km/hr
2016 – Cyclone Vardah – Chennai- 122 km/hr
1994 – Madras Cyclone – Tambaram – 116 km/hr

10. Official wind speeds and Gusts in Chennai from cyclones in last 50 years

(MSW of 50 km/hr and Gusts of above 60 km/hr at crossing)

Sustained winds
———————
1966 Madras Cyclone ~ Estimated 130-140 km/hr
Cyclone Vardah (2016) – Meena 102 km/hr, Nunga 93 km/hr and Ennore 89 km/hr
1994 Madras Cyclone – Nunga 90 km/hr and Meena 80 km/hr
1943 Madras Cyclone – Nunga 90 km/hr
1972 Sriharikota Cyclone – Meena 90 km/hr
1973 Mid November Cyclone – Meena 90 km/hr
Cyclone Nilam (2012) – Nunga 74 km/hr and Meena 65 km/hr
1996 December Madras Cyclone – Meena 74 km/hr
1982 December Cyclone – Meena 70 km/hr
1984 Sriharikota Cyclone – Meena 65 km/hr
1996 June Andhra Cyclone – Meena 61 km/hr
1979 Nellore Cyclone – Meena 61 km/hr
Cyclone Jal (2010) – Ennore 61 km/hr
1976 last week November Cyclone – Meena 61 km/hr
Cyclone Nivar (2020) – Meena 52 km/hr

Gusts
——-
Cyclone Vardah (2016) – Meena 139 km/hr
1994 Madras Cyclone – Nunga 132 km/hr
1996 December Madras Cyclone – Meena 92 km/hr
Cyclone Nilam (2012) – Meena 83 km/hr
Cyclone Nivar (2020) – Meena 71 km/hr
1996 June Andhra Cyclone – Meena 67 km/hr
2005 Chennai October Deep Depression – Meena 55 km/hr

11. Strongest cyclones in terms of pressure to cross Tamil Nadu / SL in last 40 years during NEM

(Min 975 mb pressure at any point of life time)

1978 SriLanka Cyclone – 953 mb
2000 Cuddalore Cyclone – 959 mb
1996 Chennai Cyclone – 967 mb
1993 Karaikkal Cyclone – 968 mb
2011 Cyclone Thane – 969 mb
2000 SriLanka cyclone was 970 mb
1984 Cuddalore Cyclone was 973 mb
2018 Cyclone Gaja – 975 mb
2016 Cyclone Vardah – 975 mb
1984 Sriharikota Cyclone was 975 mb

12. Highest 24hrs rainfall in Tamil Nadu from Cyclones in North East Monsoon in last 10 years

Cyclone Phyan – 820 mm in Ketti, Nilgiris in November 2009
Cyclone Nisha – 656 mm in Orathanadu, Thanjavur in November 2008
Cyclone Ockhi – 451 mm in Papanasam Dam, Tirunelveli in
Cyclone Vardah – 382 mm in Shollinganallur, Chennai in December 2016
Cyclone Nivar – 279 mm in Villupuram in November 2020
Cyclone Nilam – 240 mm in Yercaud, Salem in November 2012
Cyclone Gaja – 197 mm in Kodaikanal, Dindigul in November 2018
Cyclone Thane – 180 mm in Kallakuruchi, Villupuram in December 2011
Cyclone Jal – 160 mm in Gingee, Villupuram in November 2010

13. Do and Dont’s during Cyclones for Public.