7 June 2016
They are anxiously awaiting the monsoon in India. It will bring flooding rains, but at least it will cool the temperatures back to near 33°C, instead of the 47°C they saw in some spots today! That is over 118° on the old Fahrenheit scale, but that’s only part of the story: The dew-point reached 25-27°C, and that is heat and humidity that almost no part of America has ever seen. This is deadly heat, even in the shade, and with this much moisture in the air, the temperatures do not drop at night, so there is little relief unless you have air conditioning, and many in India would consider that an unaffordable luxury.
Our bodies cool themselves with evaporational cooling, and when we sweat the moisture cools our skin as it evaporates. You can measure how much cooling you will get by placing a wetted cotton wick on the bulb of a thermometer, then swinging it for about 45 seconds, and looking at the temperature. This is the WET BULB temperature, and from it you can derive the dew point and the relative humidity. Think about this though, if the wet bulb gets much above 90°F degrees your body is going to get very little cooling, and it will start to heat up. The wet bulb was certainly near or above 30°C (86°F) today on parts of India, and this is approaching the level of deadly heat.
Now, think about this… If India warms like the rest of the land masses over the next several decades, then it is very possible, we will start to see wet bulbs over 32°C before the summer monsoon arrives.
That is literally too hot for humans to exist in.
The summer monsoon is already arriving in India with rain over the southern parts of the sub-continent, and I have a map below from the India Weather Service that shows the expected dates that the Monsoon will arrive across the rest of the country. It will be very welcome!
Here is the view from the Terra satellite on Tuesday afternoon. Note the thunderstorm activity over southern areas of India, and also the smoke and haze over NE India, that is pretty much a constant due to cooking fires and automobile pollution.
Note: You might say that Death Valley regularly sees temperatures of nearly 125 degrees, but the air there is very dry, and if you’re in the shade, with water, you can survive this, because your skin will cool due to the low wet bulb temperature.