Two days is a long time in Weather and most of Tamil Nadu witnessed it after Cyclone Ockhi last week. When most of the watch was on a possible Bay disturbance to develop last week pretty much out of nowhere except for those who were tracking it actively Cyclone Ockhi made its move changing the entire dynamics topsy turvy. While most of Tamil Nadu was briefed about possibility of heavy rains on 4th & 5th as estimated by Models a couple of days back, we are heading for a possibly dry day across the state as model estimates were kicked out of the window by the fighting Cyclone Ockhi.
Now once again Cyclone Ockhi indirectly is influencing the weather dynamics of Bay. A week back Models were estimating a possible Cyclone / Depression to head towards North TN coast early this week. Unfortunately models possibly underestimated the staying power of Ockhi which continues to survive amidst dry air intrusion & increasing wind shear. The Well Marked Low which entered Malay Straits on 1st Dec. 2017 continues to broadly remain in the same region moving just about 300 kms over the last 60 hours or so
Over the last week or so even before Cyclone Ockhi intensified into a Very Severe Cyclone our stance has been very clear about not wanting to jump the gun on the possible Bay System. Once Cyclone Ockhi formed we have been constantly reminding about the possibility of the Bay Low Pressure finding it difficult to enter into Bay of Bengal until the influence of Cyclone Ockhi fades away. As models continued to underestimate the influence of Cyclone Ockhi they continued to show the probability of a Cyclone / Depression heading the way of North TN / South AP.
“முதல் கோணல் முற்றிலும் கோணல்” is a perfect proverb for Numerical Weather Models. If the Initial Conditions are not captured correctly the parabolic errors will start showing up on a larger scale as the days progress. What is a small error at 24 Hours window will get magnified beyond imagination by 120 Hours creating a scenario which is not in sync with reality. For some reason which possibly we are not qualified enough to comment upon Numerical Models have been underestimating the development of Cyclone Ockhi from Day 1.
In the meanwhile a small check on the expected wind pattern by models indicate if the Bay Low Pressure consolidates and starts putting its best foot forward we can possibly look at a NW track initially and then subsequently a NE track beyond Kakinada Latitude under the influence of the incoming Upper Air Trough & the Ridge over Indo China region.