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Friday, May 31, 2013

the time has come. the south west monsoon will set in over kerala tomorrow the 31st of May.  IMD will take 24 hours more and declare the onset on 1 St of  June. rain is forecast for most of southern peninsula. Bangalore will get heavy showers on 1st and 2nd. Chennai on the 3rd. onset over Bangalore is the third.

Sunday, May 19, 2013

Arrival of the South West Monsoon



The South West Monsoon has arrived over the Andaman and Nicobar islands. IMD will declare its onset within the next 24 hours. 

Two low pressures are forecast to come up on either side of the  peninsula within the next 72 - 96 hours and drag monsoon winds onto the mainland. However, the Arabian sea low is forecast to end up in Oman and could cause a delay of about 2 days in the onset over Kerala. The North-West of the country is heating up considerably and the annual Low pressure area will form over parts of Rajasthan and Madhya Pradesh, further strengthening Monsoon flows on the mainland. 

Expected date of Monsoon onset over Kerala is between 29th and 31st of May.

Monday, May 13, 2013

Cyclone Mahasen and the Onset of the Monsoon


As forecasted a cyclone formed in the bay which was named Mahasen. Mahasen is expected to make landfall between bakkhali in West bengal and chittagong in Bangladesh. Expected time of landfall is estimated between the morning - evening of the 16th of May. Mahasen is expected to strengthen for another 24 hours possibly reaching a maximum strength of T4.0 by Dvorak technique or category 2 on the saffir - simpson scale before it starts to recurve towards the North-East and weaken before making landfall as a deep depression.

 Rain/Drizzles From Mahasen is Expected along the east cost of India from Nagapattiam to Machilipattinam from the Night of 12th May 2013 to the Evening of 14th May 2013. Rain will be generated from localised Thundershowers as Mahasen pulls moisture and from bands of convection breaking off from the main system and hitting the coast. rainfall will move northwards along the coast as Mahasen makes its way north.

Pre-monsoon showers will continue over interior southern peninsula after the exit of Mahasen on the 17th.

SOUTH WEST MONSOON will reach Andaman islands by the 19th/20th of May 2013 aided by a possible low pressure near the east coast of Sri lanka. Some models also predict a Low pressure in the Arabian sea dragging monsoon winds over the mainland. 

Thursday, May 2, 2013

South West Monsoon - Two Fortnights Away!!

It has been a long delay since my last post. A horrid eight months recovering from broken bones in four different places in my body after a wonderful storm chasing (should really be calling it tornado chasing)  trip in Nebraska, US. A long story which I'd like to save for a later date.

Getting back to the weather this year, which has been a mixed bag for the country as a whole. We are already into May and No heat waves recorded or reported anywhere in the country. While the North East has been having copious Thundershowers through April the North and North West remained dry except for a few western disturbances that passed over Jammu & Kashmir and Himachal. The States of Maharashtra, Rajasthan and Gujarat remained mostly dry but temperatures have stayed pretty cool as well. 

The Southern Peninsula (My favourite part of the country) has been a joy to watch, Temperatures in the Interior Tamil Nadu and Karnataka have been pretty high throughout April with Bangalore getting close to 38 degrees on a couple or more days. The heat belt of Vellore - Vaniyambadi too had its share of high temperatures but unfortunately no records so far. However, In the midst of all this heat there have been regular Thundershowers throughout the region bringing down temperatures for a day or so. Chennai on the other hand has been quite cool by its standards all through  April with a couple of days of light rainfall towards the end of the month bringing a lot of joy to the people of that glorious city.

With April done and dusted, we move on to may - the most exciting and expectant month of the year, as huge thundershowers water the entire country and the people wait in hope for the arrival of a good monsoon.

To Begin the analysis of this years pre monsoon and monsoon period we rely on a precursor to the monsoon every year - The Summer Cyclones. This year will be no exception as Japanese and Thai forecasters are already tracking a weak low moving across the South China Sea into the Bay of Bengal. With Sea Surface Temperatures (SST) varying from 30 - 32 degrees everyday in the Bay the system is expected to gain strength and moisture quickly. It is expected to hit land around the 10th of May. For all those expecting a lot of rain from this system throughout the peninsula there's a bit of bad news, as the system is expected to kep low and majority of rainfall is expected around  Nagapattinam, Comorin and Sri Lanka. Some models also expect the system to move across the tip of the country and re emerge in the Arabian Sea. Most regions above the extreme south peninsula of the country should receive anywhere from 5 - 30mm a day from this system spread over 4 days, from 9th - 12th of May. 

Pre Monsoon showers across South India should start from the 15th onwards and is expected to be 120% of the Normal, which means most regions should see excess rainfall for May.

The second LPA for the season should arrive around the 24th or 25th of May and the end of which should coincide with the Arrival of the monsoon winds over the Andamans.

I see the Monsoon arriving over the Andamans on the 27th or 28th of May and over the southern tip of India on the 2nd or 3rd of June which is pretty normal compared to the long period average. Rainfall is forecast to be Normal at 98 - 102% of the LPA (According to IMD). I see this as a year for the North East, which should see 108 - 112% of the LPA. The rest of the country should be pretty normal except for the Southern Peninsula which should see slightly above average numbers for June and July (Between 104 - 108% of LPA). And slightly below normal rainfall in August and September (Between 92 - 96% of LPA). All in all it seems like a very normal monsoon for the entire country. For people looking for flooding, this year will have its share of floods, but they will be few and far apart. First floods will be reported from the North East which will then head to the west and then to the states of Bihar and Chattisgarh. 

A lot more detailed report on forecast drought areas and flooding areas will be published by the end of the month. Till then, enjoy the wonderful month of May and stay safe from lightning.