Weakest polar vortex for October in 40 years could affect winter weather across North America and Europe
The polar vortex forming over the Northern Hemisphere in 2024 is at its weakest point for early October in the last 40 years, with potential consequences for winter weather patterns across North America and Europe. The vortex’s unusual behavior this season could lead to significant disruptions in cold outbreaks in parts of the eastern United States, Canada, and Europe.
Image credit: Climate Reanalyzer
- The polar vortex over the Northern Hemisphere is at its weakest point in early October in 40 years, potentially affecting winter weather patterns.
- This weakened vortex increases the likelihood of cold air escaping from the polar regions, potentially causing cold outbreaks in the eastern U.S., Canada, and Europe.
- High-pressure anomalies over the Pacific and Greenland are disrupting the vortex’s structure, further influencing atmospheric circulation and weather outcomes.
The polar vortex forming in the stratosphere over the Northern Hemisphere this year has been the weakest in early October in the past 40 years.
Typically, the polar vortex contains cold Arctic air, preventing it from escaping. However, in its current weakened state, the vortex is causing shifts in atmospheric circulation. This weakening may allow cold air to escape from the polar regions, potentially affecting winter weather patterns across North America and Europe.
According to a report by Andrej Flis published by Severe Weather Europe, this phenomenon could increase the likelihood of cold outbreaks in the eastern United States, Canada, and parts of Europe.
Currently, the polar vortex is smaller than usual, with a slight displacement toward Siberia. Over the Pacific Ocean, a high-pressure anomaly has been developing in the stratosphere, pushing the center of the vortex and limiting its strengthening.
Normally, the vortex strengthens and extends fully to the lower levels of the atmosphere during October. However, the high-pressure anomaly surrounding the vortex at the stratospheric level is pressing against it, hindering its development and affecting its structure.
For the first two weeks of October, the vortex is expected to weaken further and reach its weakest point for this time of year in the past 66 years. This suggests a disruption in the upper and lower levels of the atmosphere, which could transfer downward, altering weather patterns.
A strong high-pressure anomaly over Greenland will push deep into the polar regions, nearly breaking the vortex into individual areas. At the same time, a pair of high- and low-pressure areas in the North Pacific and Aleutians are driving energy into the stratosphere.
As the vortex grows in October, its expansion is being blocked on the western side due to the high-pressure anomaly, causing it to extend over North America.
The North Atlantic Oscillation (NAO), which is linked to the strength of the vortex, is forecast to remain in negative values for at least the first half of October. Typically, a negative NAO index would indicate increased chances of snowfall and cold outbreaks across the eastern United States. However, snow and cold are not yet certain, as the pattern could still be disrupted in October.
References:
1 Unusually weak Polar Vortex is developing in the Stratosphere, linked with the Weather patterns over the United States and Canada – Severe Weather Europe – October 4, 2024
Rishav is a skilled researcher specializing in extreme and severe weather reporting. He combines exceptional research capabilities with scientific precision to deliver clear, data-driven articles. Known for uncovering critical information, Rishav ensures his work is accurate, insightful, and impactful. His passion for both science and literature fuels his dedication to producing high-quality news articles. You can reach him at rishav(at)watchers(.)news.
Commenting rules and guidelines
We value the thoughts and opinions of our readers and welcome healthy discussions on our website. In order to maintain a respectful and positive community, we ask that all commenters follow these rules.