Source : INDIA TODAY NEWS
If you live anywhere between Punjab and Uttar Pradesh, the next few days will test your patience and your water bottle. After a short lull, north and central India is bracing for a fresh blast of heat, with the mercury set to climb from Monday, June 8.
Independent weather forecaster Navdeep Dahiya has flagged a sharp rise in daytime temperatures across Punjab, Haryana, Rajasthan, Delhi-NCR and Uttar Pradesh, with maximums touching 42 to 46 degrees Celsius. The peak is likely around June 10 and 11, before some relief arrives by Friday.
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WHY THE HEAT IS BUILDING
The main culprit is a steady stream of hot, dry winds blowing in from the northwest. Scientists call this advection, which simply means heat being carried from one place to another by the wind.
Here, the winds sweep across the Thar Desert and the dry plains of Rajasthan and Pakistan, soaking up heat as they travel.
These are the infamous loo winds, the dusty, parching gusts that strip moisture from the air and from your skin. Because they keep flowing, any cool air that forms locally is quickly shoved aside and replaced with more hot air.
THE INVISIBLE LID OVERHEAD
There is a second player at work high above us. A ridge of high pressure, also called an anticyclone, often parks itself over the region. Picture an invisible lid that presses warm air downwards.
As this air sinks, it gets squeezed and warms up further, a process known as subsidence.
The lid also clears away clouds, so the strong June Sun beats down with little to block it. The outcome is sometimes called a heat dome, where warmth is trapped near the ground.
Dry soil makes it worse. With little moisture left to evaporate, almost all the Sun’s energy goes into heating the air rather than turning water into vapour, which is why parched land bakes fastest.
WHEN HEAT MEETS IMD’S BAR
The India Meteorological Department (IMD) declares a heatwave in the plains when the maximum crosses 40 degrees Celsius and runs at least 4.5 degrees above normal, or simply when it touches 45 degrees, whatever the normal.
A forecast of 42 to 46 degrees clears that bar comfortably, especially across west Rajasthan and the Bundelkhand belt of Uttar Pradesh.
WHEN WILL HEATWAVE BREAK
Relief is on its way. A western disturbance, a band of moisture-carrying winds that travels eastward from the Mediterranean, is expected around June 13.
It will bring clouds, a chance of rain and a change in wind direction, knocking the temperature down by a few degrees.
For now, the monsoon, which reached Kerala on June 4, is still far from the north. Until it climbs up the map, these short, fierce heat spells will keep returning.
So keep the curtains drawn, the water close and the loo at arm’s length.
– Ends
SOURCE :- TIMES OF INDIA
