A significant meteorological event is poised to impact the contiguous United States next week, as the stratospheric polar vortex undergoes a rare split, leading to an arctic outbreak with temperatures projected to plummet 20 to 40 degrees below normal between February 17th and 23rd.
Understanding the Polar Vortex Split
The polar vortex is a large area of low pressure and cold air surrounding both of Earth’s poles, residing in the stratosphere. Typically, this vortex remains stable, containing the cold air within the polar regions. However, certain atmospheric conditions can disrupt this stability, leading to a phenomenon known as a Sudden Stratospheric Warming (SSW). During an SSW, large-scale atmospheric waves, called Rossby waves, propagate into the stratosphere, weakening the polar vortex. If these waves are strong enough, they can cause the vortex to split into two or more smaller vortices. This split allows frigid polar air to descend into mid-latitude regions, including parts of the United States.
Projected Temperature Anomalies
Forecast models, including the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Global Forecast System (GFS), indicate that one of the split vortex cores will migrate over North America. This movement is expected to usher in a significant cold air outbreak across the northern, central, and eastern United States. Temperature anomalies during this period are projected to range from 20 to 40 degrees below normal.
Potential for Increased Winter Storm Activity
The influx of arctic air sets the stage for enhanced winter storm development. As the cold air interacts with warmer, moisture-laden systems from the south, the likelihood of snow, ice, and mixed precipitation events increases. Regions across the central and eastern U.S. should prepare for potential winter storms during this period, with the possibility of significant snowfall and hazardous travel conditions.
Preparing for the Arctic Outbreak
Residents are advised to monitor local weather forecasts and heed warnings from meteorological authorities. Preparations should include:
- Ensuring adequate heating supplies and checking the functionality of heating systems.
- Stocking up on essential items in anticipation of potential disruptions.
- Taking necessary precautions for vulnerable populations, including the elderly and those with health conditions.
- Preparing vehicles for winter conditions, including checking antifreeze levels and ensuring tires are suitable for snow and ice.
By staying informed and taking proactive measures, individuals and communities can mitigate the impacts of this impending arctic outbreak.