Citizens, get ready, the polar vortex is about to collapse

As autumn advances, the decrease in solar energy causes a significant cooling of the polar stratosphere, which creates a strong temperature difference between the cold polar and warmer subtropical regions.

This difference drives a large low-pressure circulation, known as the polar vortex, that extends from the Earth's surface high into the atmosphere.

The meteorologist warned: A polar vortex is coming to Serbia

The polar vortex plays a key role in shaping winter weather in North America, Canada and Europe.

When the vortex is strong, the enhanced jet stream traps cold air within the Arctic Circle, often resulting in milder winter conditions in the mid-latitudes.

However, if the vortex weakens or collapses, which has happened over the past few winters, cold air can move more freely southward, bringing cold temperatures and potentially snow to regions like the United States and Europe, Severe Weather said.

Two key factors could shape the coming winter of 2025/2026: La Niña and the Quasi-Biennial Oscillation (QBO)

La Niña, an anomaly of cooler surface temperatures in the tropical Pacific Ocean, increases the probability of stratospheric warming (SSW) events by 60-75%, which can lead to polar vortex collapse, especially in mid- to late winter.

Historical records show that such events often resulted in extreme cold in the mid-latitudes.

The QBO, the regular reversal of wind direction in the tropical stratosphere between easterlies and westerlies every 17 months or so, also plays an important role.

The negative (easterly) phase of the QBO further weakens the polar vortex, increasing the chances of jet stream disruptions and cold air bursts.

The combination of La Niña and a negative QBO therefore suggests a higher likelihood of a dynamic winter with unstable weather patterns.

In early October, the temperature forecast shows the development of a cold core above the Arctic Circle, which is the heart of the polar vortex.

A cooler core may strengthen the vortex in the early stages of winter, but the strengthening of La Niña and the QBO suggests that the vortex may weaken later in the season.

If the vortex collapses, regions like the United States and Europe could experience colder temperatures and an increased likelihood of snow, reports Večernji list.

Experts warn that these conditions are only part of the complex puzzle of global weather patterns.

Although La Niña and the QBO increase the chances of an unstable winter, the exact outcome will depend on additional atmospheric and oceanic factors.

Citizens in the mid-latitudes should prepare for potentially changeable weather in the coming winter season.