Massive disruption in winter weather engineered by a ‘polar vortex’ will pump a blast of frigid air into eastern parts of the US, rendering Donald Trump’s second inauguration as President the coldest in at least 40 years, according to weathermen. 

“Heading into the evening on Monday, the polar vortex will take complete control of the Lower 48,” said Ryan Maue, private meteorologist on X. ‘Lower 48’ refer to the contiguous states of the US that touch each other, excluding Alaska or Hawaii. 

• Read also: Mukesh Ambani, wife Nita to attend Donald Trump’s inauguration

First after Reagan

Trump’s inaugural on Monday has been moved indoors due to ‘dangerously cold weather’. The inaugural parade will also be held indoors in downtown Washington. The last president to be sworn-in indoors due to extreme cold was Ronald Reagan in 1985.

The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles, explains US National Weather Service. It always exists near the poles, but weakens in summer and strengthens in winter. The term vortex refers to counter-clockwise flow of air (hence ascending air and lower pressure) that helps keep the colder air near the poles. 

Strong westerly winds

The polar vortex is a band of strong westerly winds located 16-50 km above Earth’s surface in the stratosphere while polar jet stream occurs in troposphere at altitudes of 8-14 km. The jet stream marks the boundary between cold polar air and warmer mid-latitude air, and can dip south from its usual perch circling the Arctic and bring freezing cold temperatures.  

The last time a polar vortex made news was during the 2013-2014 winter when a high-pressure system in the Pacific pushed the northern polar vortex southward, contributing to a cold, snowy and icy winter in Northern America (US and Canada).

• Read also: Currency Outlook: All eyes on Trump’s inauguration

Records broken in 2014

Snow blanketed mountains in western US by December 2013. By January and February 2014, record-breaking low temperatures and snowfall were reported from parts of Canada and the eastern US. New York, Philadelphia and Chicago all had one of their 10 snowiest winters. Detroit had its snowiest winter on record. Previous notable events occurred in 1977, 1982, 1985 and 1989. 

Closer home, polar vortex and polar jet stream find nearest possible expression in alternating wet spells and dry cold over North India, as modulated by western disturbances. These disturbances originate in the Mediterranean, and are sub-tropic perturbations associated with the polar jet stream, a ribbon of fast-moving air across the globe from west to east. Arctic air being forced down towards by the jet stream towards equator ramps up strength of these western disturbances.