WEST MICHIGAN -- Most of us heard the term earlier this decade...POLAR VORTEX. I'm guessing most people understand that it translates to cold, cold air. That's true...but perhaps brutally cold air may be more appropriate.
The term POLAR VORTEX is easy to understand. I'll use the definition from Wikipedia since it's simple: "A polar vortex is an upper level low-pressure area lying near the Earth's poles. There are two polar vortices in the Earth's atmosphere, overlying the North and South Poles. Each polar vortex is a persistent, large-scale, low pressure zone that rotates counter-clockwise at the North Pole (called a cyclone), and clockwise at the South Pole. " Occasionally, these polar vortices (or a fraction thereof) can break free from the pole and rotate into the northern United States. It doesn't happen often, but it does happen. The last time this occurred of any significance (I believe) was in the winter of 2013.
The absolute core of the coldest Arctic air is part of this POLAR VORTEX. When it drops southward into Canada and sometimes into the United States, it gives new meaning to the term winter. Temperatures generally plummet and any wind chill can be brutal...sometimes on the order of -30 to -50 below zero, dangerous/life threatening to say the least!
Take a look below at what our forecast model is showing for next week late Tuesday/Wednesday/Thursday. The colors on the map represent the air masses. The warmer tones of green and yellow are over Florida and California, but note the "POLAR VORTEX or low" dropping into the Great Lakes and the colors on the map of white and magenta.
In fact, temperatures were so cold on this map, our color table didn't go low enough. We had to actually add the "magenta" over northern Minnesota and southern Canada. That color signifies air temperatures (not wind chills) of -40 or lower! Our temperatures in West Michigan next Wednesday/Thursday may struggle to get above zero. Locations down wind of Lake Michigan may get into the single digits due to some "lake modified" air, but many other locations may not reach zero. Wind chills may be on the order of -30 to -40. Only eight times in the history of weather record keeping (since the 1880s) has Grand Rapids had an air temperature of zero or lower. The last time was 25 years ago on January 19, 1994!
Take a look at another forecast model image below...valid for next Wednesday morning. It shows the POLAR VORTEX just north/east of the Great Lakes (low) and temperatures about 5,000 feet above the surface at -30 degrees Celsius. That's about -22 Fahrenheit. At the surface...that's likely below zero! Funny thing here? This map also literally ran out of colors, so the model has to start repeating warmer tones of yellow/red/green to "fill the void."
Prior to the arrival of this brutal air and POLAR VORTEX will be the chance of a significant snow maker arriving on Monday (perhaps 6" or more), then heavy accumulating lake effect snow Tuesday/Wednesday/Thursday. With westerly winds progged (shown) by our forecast models, that means the heavy snow would be dragged all the way into the U.S. 131 corridor westward.
Make sure the batteries are ok in the car, tune up the furnace, and please make sure NEVER EVER run generators inside the house or garage. They produce deadly carbon monoxide fumes. Space heaters are fine, just keep them away from curtains and other surfaces that can burn.