One of the biggest challenges Weather Agencies across the world face is how to effectively communicate weather alerts. On the one hand weather alerts should be simple enough for most people to understand while continuing to ensure the severity of the situation is not lost in the process of making it simpler. Even bigger challenge is how to ensure large parts of the public are aware of what a particular warning means. Over the past few years as social media brought about a change in how information dissemination happens often we have seen Red Alerts from India’s weather agency, IMD, being ridiculed. In an efforts to create a space for themselves in ever changing social media world even the mainstream media have opted to join the bandwagon proving the old saying “If you can’t beat them, join them” right.
Just like rainfall classification, both daily and seasonal, IMD has fairly robust classifications for Heatwave as well. The Heatwave warning is not only tabulated for the plains and hills separately but takes into account both actual and anomalous temperatures while providing the warning. To cut a long story short for the interior plains the daytime max temperature should be at least 40°C with an anomaly of at least 4.5°C over a minimum of two stations for two consecutive days. IMD also has made an exception for coastal stations where if temperatures touch at least 37°C with a similar 4.5°C anomaly there is potential for heatwave warning. In the event the actual temperatures cross 45°C for two consecutive days over two stations then a heatwave warning will be issued irrespective of the anomaly part. One of the key reasons why heatwave warnings are put in place is to ensure not only administration is better prepared but also common public plan their activities in order to avoid stepping out in the afternoon sun when peak temperatures are expected to prevail.
The IMD has issued a heatwave warning for parts of North Interior Karnataka this weekend and also for Rayalaseema region of AP and Telangana state on Monday. Weather models indicate the next 7 to 10 days may see abnormally hot day time conditions with temperatures expected to be 4 / 5°C above normal over most places in the region. Though today most of Tamil Nadu may see a slight reduction (a degree or two) compared to the past couple of days due to the weak moisture being pushed by Easterlies and possibly light drizzle / rains over a few pockets of the state interior areas of Karnataka, AP and Telangana will continue to see hot daytime conditions.
Starting from tomorrow the temperatures are expected to increase by another couple of degrees over the next week to 10 days with most parts of Rayalaseema and adjoining areas of Telangana seeing maximum temperatures peak around 42 / 43°C with one or two places likely to see high 43°C or even inch closer to 44°C when the peak phase of this spell hits between Friday and Sunday. Places in Tamil Nadu may not be this bad though there is a very high chance interior West TN and parts of Central TN may see maximum temperature get close to 41 / 42°C over many places during the second half of the upcoming week. North TN is a late arrival to the heat party always as far as Summer goes with Easterlies keeping a check on temperatures. While things may not be that bad for Chennai and suburbs there is increasing consistency among models between Thursday and Sunday some of the western suburbs of Chennai may see day time temperatures peak around 40°C.
The dry weather conditions in a way is aggravating the heat currently seen over Peninsular India. Sub seasonal models indicate below normal summer thunderstorms is expected to continue until pretty much end of April with things expected to take a favourable turn at the start of the 4th week for interior areas of Peninsular India. Till then all the weather talk is likely to be on the heat and nothing but the heat for Peninsular India