West Coast Wakes Up as Southwest Monsoon set for revival

In a news which is likely to bring a lot of Cheer the west coast has started waking up from its mid season slumber as Southwest Monsoon is set for a revival under the influence of the Low Pressure area that has formed in the Bay of Bengal. While the revival is not likely to bring active monsoon conditions immediately the current spell of dry weather is likely to be broken. Since July 31st the Core Monsoon Zone Standardized Rainfall Chart is below average bringing the overall monsoon average to -5.1% as of yesterday.

Things have started to pick up on the West Coast already with some of the places starting to record meaningful rains.  Hulikal, Madikeri, Munnar, Anakayam have recorded moderate to heavy spells of rains yesterday with possibly things improving further from today as the Low Pressure moves inland making its journey across the Northern parts of Peninsular India.

Thanks to the formation of the Low Pressure in Bay the monsoon trough which has parked itself in the foothills of Himalayas for more than a fortnight will slowly get dragged south closer to the Low Pressure Area as it traverses across the land.  This movement of trough is a key ingredient in breathing life back into monsoon dynamics with possibly the subsequent Disturbance in a few days possibly making things pick up on the monsoon front.

Closer home yesterday saw parts of Chennai, in particular around the Northern suburbs of the city enjoyed heavy thunderstorms late in the evening while most other parts of the city also enjoyed moderate rains.  As was the case day before yesterday while the interior parts of Tamil Nadu around Salem, Tiruvannamalai, districts enjoyed some spells of rains the most intense action happened in the extreme parts of North TN around Chennai.

As mentioned in our yesterday’s post we could possibly see a temporary break for us in terms of active thunderstorms with West Coast waking up from its slumber.  While isolated thunderstorms may continue the increased wind speeds triggered by the low will no more allow thunderstorms to develop intensity and drop heavy rains in one place.


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Parting gift to Chennai as rains expected to ease over Tamil Nadu

It was a “Chennai Special” yesterday from the Thunderstorms as most of Tamil Nadu saw little rains while places within 50 – 100 kms of Chennai saw the bulk of rains as continuous rains lashed across the city from evening till well past midnight bringing much cheer to the citizens of the metropolis. It is a common discussion among weather bloggers when Chennai gets rains the rest of the place remain spectator, yesterday proved this once again.

In what could be considered as the first fully widespread of rains for the city this season most of the IMD observatories in the city recorded 4 to 6 cms of rains as both Nungambakkam & Meenambakkam observatories recorded an identical 61 mm rains till 5:30 in the morning.  In the past we have seen some parts of the city record intense rains while many others missed out which was not the case yesterday.

In the past more often than not Chennai possibly gets the last good spell of rains before the thunderstorm season takes a break from this part of the country and monsoon dynamics shifts back to rest of the country.  Yesterdays could possibly turn out to be that defining spell that is likely to bring a shift in dynamics. With Bay of Bengal churning out the next disturbance in a day or two we are going to see the typical monsoon dynamics change once again and the rains are expected to ease over Tamil Nadu. While there is a slight chance of some afternoon / evening rains in the extreme North TN around Chennai overall the rains will start to fade away.

Under the influence of the Upper Air Cyclonic Circulation in the vicinity parts of Coastal AP & Telengana is likely to see rains at most places with a few places likely to see moderate to heavy rains today.  Similarly we can see some bit of momentum build over the West Coast as well thanks to the moisture drag created by the circulation.

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Thunderstorms continues its Sojourn over North Tamil Nadu

Thunderstorm’s  fascination for North Tamil Nadu continues as yesterday extreme northern parts of the state were witness to moderate thunderstorms in the evening with isolated places getting an intense burst near the coast.  Highlights of the day include Anna University which recorded nearly 7 cms in a two hour spell between 3:30 & 5:30 PM while both Nungambakkam & Airport observatories also recorded decent spells of rains as most parts of Chennai enjoyed the rains.

While overall the majority of the rains happened in North Tamil Nadu, a few parts of South TN and delta districts got isolated spells of thunderstorms with Kudavasal recording about 5 cms of rains through late evening / night.  Things are slowly moving towards the monsoon dynamics as we mentioned in our yesterday’s post. While we will continue to see thunderstorms in Tamil Nadu the spatial spread will start slowly reducing in the days to come.

As was the case yesterday today also we are likely to see parts of North Tamil Nadu,adjoining parts of Rayalaseema and South Interior Karnataka better placed to enjoy the evening thunderstorms.  It appears today once again parts of Bengaluru could see moderate to fairly intense thunderstorms in one or two places.

The districts of Tiruvannamalai, Tiruvallur, Kanchipuram, Vellore and parts of Chennai could see evening thunderstorms develop with Westerlies picking up pace we can possibly see slightly faster moving thunderstorms which could mean movement towards the coast and possibly providing lesser intense spells compared to the past few days.


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Isolated Thunderstorms continue over North Tamil Nadu

Tamil Nadu continues to see one of the best Southwest Monsoon periods in recent times as it touched 30% excess as of yesterday clocking its 6th day of Daily Mean Rainfall exceeding 10 mm.  All of these days have come in August which is a noteworthy point.  While Sunday did not see the widespread thunderstorms that were seen on Saturday it did see its share of some intense storms around Vellore, Kanchipuram & Tiruvannamalai districts with the Southern suburbs of Chennai seeing extremely intense rains lash for 30 minutes or so bringing localized water logging around Mudichur areas.

Isolated rains are likely to continue in a few places of North Tamil Nadu today as well with Vellore, Tiruvannamalai, districts in line for one or two places getting moderate thunderstorms.  As has been the case parts of Chennai could see localized thunderstorm development in one or two places bringing some sharp spells during the late afternoon / evening.  Overall things could start to ease slightly as Monsoon dynamics starts moving back to the West Coast with possible disturbance evolving in the Bay.

In the meanwhile for the month of August Polur & Chengam of Tiruvannamalai districts top the rainfall charts in the plains of Tamil Nadu & Pondy.  Both places have recorded 42 cms so far most of which in the last week or so.  If one were to represent the Top 20 places in the plains spatially its quiet clear the gaps, passes and low altitude dips in Western Ghats play a crucial role even for the convective thunderstorms indicating the overall monsoon dynamics in the entire process.

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