Stratospheric Disruption, Surface Consequences

A downward trend to spring is likely to be underway.

Back in early February, we flagged that the stratosphere was undergoing a series of warming events. Those perturbations have continued through the month, weakening the stratospheric polar vortex and setting the stage for a more significant disruption.

The observational signal became clear by mid-February and is now propagating downward into the lower stratosphere. A major warming event is expected in early March, likely resulting in a wind reversal at the 5–10 mb level. In practical terms, this marks a substantial disruption to the high latitude circulation aloft.

This is not an unusual event in a climatological sense, but it often reshapes the hemispheric pattern through March. In essence, this is gearing down of winter in the northern hemisphere and often results in warm/cold pool tussles.