By Paula Walter
The frigid weather of the last week have evoked memories of last winters severe cold, dubbed the Polar Vortex, a meteorology term that refers to a pocket of extremely cold air that usually circles the North Pole. This year, the new buzz word for the artic blast much of the eastern portion of the United States has been experiencing from Maine to Alabama is referred to as the Siberian Express. The difference between the two is the winds associated with this system come from Russia, travel around the Artic Circle, make its way into Canada and then into the United States. Regardless of the name, the results are the same: It is bone-chilling cold outside.
One feature that has promoted the cold has been the upper level flow and jet stream, explained WJHL meteorologist, Brian Walder. In short, the general pattern for this winter, especially of late, has been an upper ridge in the western United States and a trough in the east, Walder said. What this setup allows for northwest flow aloft in-between the ridge axis and trough axis. When we have this northwest flow, the source region of the air blown our way is Canada, and this allows for cold air to settle in the eastern United States. This air is often moved from Canada into the United States via arctic areas of high pressure. When it comes to winter forecasting, finding the high just as important as the actual storm because the placement and strength of the high will determine where and how strong the cold air is. Another general rule is that cold air is found on the poleward side of the jet stream, and warmer air is found on the equatorial side. So between the ridge/trough setup allowing for a dip in the jet stream over the eastern United States and northwest flow aloft and the movement of arctic areas of high pressure from Canada into the United States, cold air has been able to move into not just east TN, but much of the eastern US.
The results have been record-breaking amounts of snow, ice and rain, as well as bitter cold. It has been reported that 18 deaths related to the weather have occurred in Tennessee this past week, nine from hypothermia, five from car accidents and three from fires. The temperature in the Tri-Cities dropped this past week to -13, shattering their old record of 13 degrees above Fahrenheit in 1979. Those records have been smashed with last weeks temperatures. Water mains have broken in cities across the country, and on a local level, residents are experiencing broken water pipes and overly stressed heating units. Even businesses across the region are struggling as shoppers seek the safety and comfort of their homes.
For the rest of the story, pick up a copy of this week's Tomahawk.
By Paula Walter