Monsoon is a word, Northeast Monsoon aka NEM is an emotion for the weather bloggers & enthusiasts of Tamil Nadu. This period of about 60 days is possibly unrivaled anywhere in terms of excitement as the emotions ebb and flow along with the model outputs of Global Numerical Models like GFS & ECMWF. The period when 11:00 to 11:30 AM and 11:00 to 11:30 PM become golden hours as the two daily runs of ECMWF outputs become public. The time when names like Vardah, Thane, Nisha become more popular than Trisha & Nayanthara. Welcome to Northeast Monsoon a roller coaster ride that always surprises how much ever prepared you are.
With Northeast Monsoon just around the corner its an ideal time to take stock of the situation in terms how things are with the various IMD observatories in Tamil Nadu & Pondicherry. The table given here lists the IMD observatories with their total rainfall for the year so far along with the balance rainfall required to end with a normal year. We have classified the stations based on the rainfall required to highlight the critical & vulnerable stations for better understanding.
As was the case when we made the NEM Outlook a few days back, the most vulnerable stations are along the coast. Nagappattinam, Palayamkottai, Thootukudi are still to receive even 40% of their annual quota. While Chennai Meenambakkam has accumulated about 56% annual rains so far Nungambakkam , not far away, has got only about 45% of the annual rains. Among the places which have already got at least 90% of the annual rains Madurai is the closest to coast at about 110 kms while the other places are well perched in the interiors.
Today could possibly the last day of Westerly winds as low level winds are expected to change into Weak Easterlies from tomorrow an indication of the up coming Northeast Monsoon. Just to clarify the return of Easterlies alone do not classify as Monsoon onset but the presence of Easterly winds along with wide spread rains and the withdrawal of Southwest Monsoon up to 15N latitude will confirm the arrival of Northeast Monsoon.
Nevertheless யானை வரும் பின்னே மணி ஓசை வரும் முன்னே, the Easterlies are the first bugle towards Northeast Monsoon