24 April 2016

It's boiling! Decoding the Met department's new heat forecasts

http://scroll.in/article/806963/its-boiling-decoding-the-met-departments-new-heat-forecasts
A colourful map prepared by the IMD explains what India can expect this summer.

India has a new weather obsession. For decades, if not centuries, the monsoon was all the country paid attention to. Good rains meant a good year and so all weather-watching was focused on spotting clouds. Now there's a new player in town, one with an equally devastating impact: heat.
Weather watchers are used to waiting for the Indian Meteorological Department's Long Range Forecast that predicts how good or bad the monsoon will be. For the first time ever, this year, the IMD released a summer forecast predicting "warmer than normal temperatures... in all meteorological sub-divisions" and above normal heatwave conditions in central and northwest India.
In addition to its first-ever summer forecast, the Met department also said that it would release regular extended range forecasts, every five days from the start of April. All of this is made available on the IMD website, with the aim of putting out more information that can aid the public.
On April 21, the first thing that greets you on this new heat wave section of the IMD site is a daunting image showing heat-wave warnings across what seems like half of the country.

The colour-coded map is another novel feature of the IMD's new approach to communicating weather information, one that it intends to use across seasons. These were based on the recommendations of an expert committee of meteorologists, advising the department on how to better communicate weather data.
"Based on their intensity and potential impact, rainfall, cold and heat will be signified using red, orange, yellow and green colour-codes," DNAreported. Green suggests no weather warning, yellow asks authorities and citizens to watch and get updates, orange asks them to be alert and red is an official warning asking for action to be taken.
This April there has been a lot of yellow, orange and red. But the IMD's hot weather subsite also includes one bit that seems much more heartening: A five-day forecast that suggests by April 24th, there is no impending heatwave warning.

The sub-site is also stuffed with a bunch of other information. The daily updates include specific warnings about prevailing heat wave conditions, although this includes outdated terminology that the expert committee had recommended the IMD do away with.

For example, the prevailing information speaks of markedly above average temperatures at "isolated places over Himachal Pradesh, East Uttar Pradesh, Bengal and Kerala." This neither provides enough information about where the heat wave was occurring, nor offers enough context as to whether it will continue in that place.

The IMD has said it aims to move away from terms like "isolated places" and provide much more specific information.

"With time, the relevance of certain benchmarks has changed and the same goes for old terminologies. Since we have more tools, the people should be conveyed precise information," BP Yadav, head of the National Weather Forecasting Centre told DNA.

From May, the IMD also plans to put out a Heat Index, which will gather data from across all weather stations and be updated every three hours.

The IMD site also features a few other tid-bits, such as a useful graph that visualises temperature anomalies. This shows how much temperatures across the country has strayed from the average temperature at this time over the last century. 

Every five days it also comes with the Indian Institute of Tropical Meteorology's five-day real time forecast, which is full of data, such as temperature histograms, soil moisture levels and maps charting the daily evolution of minimum and maximum temperatures. This also includes a 15-day forecast.

According to the most recent one, there is a bit of good news.


"Major parts of India outside the southern and eastern states comprising Tamil nadu, Kerala, Andhra Pradesh, Telangana, Odisha, Gangetic west Bengal and eastern parts of Bihar are likely to cool down to their respective normal or slightly below normal day & night temperatures during 22nd-26th April."

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