Scientists observe polar vortex weakening in early November

Unprecedented timing for disruption

European Centre for Medium-Range Weather Forecast scientists stated this is the earliest stratospheric vortex disruption observed. The vortex normally strengthens through autumn and peaks around January before weakening later in winter. This early shift raises concerns about cold air moving south into Europe, North America and Asia.

Mechanics of sudden warming

Large atmospheric waves in the troposphere can surge upward to trigger rapid warming in the stratosphere. Such events weaken or reverse the vortex winds that usually circulate air from west to east. When these winds fail, the cold low-pressure region splits apart and spills southward.

Source of lower waves

Climatologist Judah Cohen explained that the vortex is disrupted from below by these large atmospheric waves. A big enough surge into the polar stratosphere causes the rapid warming known as sudden stratospheric warming. This process remains a primary factor in the current early weakening.