BIRMINGHAM, Ala. — There has been a lot of talk about a potentially unprecedented early Sudden Stratospheric Warming event developing miles above the North Pole. When these events happen, they can disrupt the polar vortex and open the door to blasts of frigid Arctic air weeks later. For Alabama, that could raise the chance of major cold snaps and possibly winter weather later in the season. However, it is still a developing signal, not a confirmed major event.
Warming High Above the Arctic
A European model forecast valid November 8 shows a large area of rising heights and warming over the Arctic. The warm area, shown in red and orange, sits near the North Pole. Cold areas, shown in blue, appear over Canada and parts of North America.
This kind of warming can weaken or displace the polar vortex. When that happens, Arctic air that is normally locked near the pole can spill south. The model map is a signal only, not a surface forecast or a confirmed event.
What Causes a Stratospheric Warming
Strong high pressure over Siberia can act like an atmospheric ramp. It channels huge waves of energy upward into the stratosphere, far above the weather we feel. This process is known as Wave Activity Flux, or WAF.
As that energy builds, it can destabilize the polar vortex. The vortex may slow down, stretch out, or even split. A disruption this early in the season would be very unusual.
No Instant Blast of Cold
An event like this does not mean an instant blast of Arctic air. The effects usually take several weeks to reach the ground. Any colder pattern would likely show up in late November or December…