Oak Hill, WV (WOAY-TV) – It’s a buzz word that will latch onto social media and the major media outlets in the next two weeks that might have more bite than bark for our region. So, what is a ‘Sudden Stratospheric Warming Event’ and how will it impact southern West Virginia’s weather?
The layer in the atmosphere above where weather occurs is known as the Stratosphere. It houses the ozone layer, which absorbs radiation from the Sun and prevents it from reaching Earth’s surface. Also up there is a fast-spinning low pressure known as the polar vortex that extends through a large depth of the stratosphere. Every year it develops around Labor Day weekend, reaches peak intensity in January and then fades away as sunlight returns to the Northern Hemisphere in the spring.
When the winds rotating around the stratospheric polar vortex become super-charged (as they have been most of this winter), the coldest air in our part of the world (Northern Hemisphere) stays bottled up in Siberia and around the Arctic Circle. However, when the winds around the polar vortex weaken rapidly and reverse direction, temperatures warm near the vortex center.
It can cause a domino effect from the upper part of the vortex into the troposphere where the weather occurs. When the Sudden Stratospheric Warming Event occurs and the rapidly decaying vortex links up with the troposphere (where the weather occurs), a large Arctic outbreak gets ejected into some portion of the middle latitudes (where we live).
It’s usually unpredictable until after the Sudden Stratospheric Warming Event gets underway where this cold air will go, but one thing usually is for certain. The cold outbreak lasts for up to a month and usually travels around the Northern Hemisphere. For instance, if the cold air dumps in Europe, it eventually moves to Asia and then to the U.S., but takes at least four weeks to arrive in the U.S.
When the cold air arrives in the U.S., the jet stream dips way far south and the storm track is optimal for southern West Virginia to see snow. The latest data suggest a sudden warming event will likely occur at the end of this month or early February.
Before you get too excited about the prospect of a big blizzard, let’s preview the archived record of sudden stratospheric warming events that have transpired in early February and how they have or have not impacted southern West Virginia.
|Date of Sudden Stratospheric Warming Event||Southern West Virginia Snowfall That Followed|
|January 30, 1958||Lewisburg accumulated 9.5 inches in February and 11 inches in March|
|January 31-February 2, 1973||Beckley accumulated 10.9 inches in February and 5 inches in March|
|February 6, 1981||Beckley accumulated 8.4 inches in February and 20.4 inches in March|
|February 9, 2010||Beckley accumulated 49.8 inches of snowfall in February and 3.5 inches in March|
|Average Snowfall for Beckley||February: 15.2 inches; March: 8.9 inches|
There you have it… only one early February Stratospheric Warming Event resulted in above-average snowfall in the year’s second month and two early February warming events resulted in above average snowfall in March. It’s also important to note that not all these polar vortex events trickle down into the troposphere and impact the weather.
Additionally, our cold blasts are not always linked to the status of the polar vortex. One such example was the Christmas Day cold outbreak just one month ago. It was simply due to a shift in the Pacific jet stream pattern that guided the Siberian express into southern West Virginia. These cold blasts unrelated to the status of the polar vortex are usually transient, lasting from a few days to a week. We saw that with the Christmas Day cold outbreak; Beckley’s high temperature soared from 10 degrees on Christmas Eve to 61 degrees just 6 days later.
The state’s second coldest low temperature ever recorded, in Snowshoe, did occur about 20 days after the early January 1985 Stratospheric Warming Event. Incidentally, that was a La Nina winter as well.
Sudden Stratospheric Warming Events are a topic of study for meteorologists. The goal is to identify their trigger and provide more lead time on their potential impacts down the road with our weather.
Stay tuned for the latest forecast from the StormWatch4 Weather Center and social media and website updates!