Here we go again. A large winter storm system is crossing over the central and eastern United States today, triggering winter storm warnings in 14 states.
A winter storm warning is issued when a forecast indicates at least six inches of snow will fall in 12 hours, or eight inches in 24 hours, or half an inch of sleet is expected to accumulate. That distinguishes it as more serious than a winter weather advisory (3 to 5 inches of snow in 12 hours, among other considerations), and a winter storm watch (which indicates the possibility of a winter storm). The latest National Weather Service map indicates winter weather advisories are in place in 28 states and flash flood watches are in place for 11 states. You can view state-by-state (and more localized) forecasts on the National Weather Service website.
“Bursts of heavy snow, accumulating at times to an inch per hour, may lead to hazardous driving conditions and disrupt travel. Heavier snow rates should develop in time for the evening rush hour in Milwaukee, Chicago, Grand Rapids, and Detroit, among other locations,” stated a NWS Weather Prediction Center forecast discussion published early Wednesday. “Plan ahead if you are commuting.”
While some regions may transform into winter wonderlands, the weather forecast indicates a significant chance of wintry mix—meaning a slew of snow, sleet, and freezing rain. Either way, the weather service cautions that “power outages and tree damage are likely” and, in sum, your safest choice is to not travel unless it is absolutely necessary.
According to EarthSky, the winter storm is caused by the southerly movement of a high pressure system from the Arctic, moving cold weather across the contiguous U.S. as moisture from the Gulf moves north. Mixing together in a low-pressure area triggered a winter storm, with its coldest (and thus most-likely-to-produce-snow) side towards the north.
As noted by EarthSky, historical data from the Storm Prediction Center in Norman, Oklahoma indicates the risk of severe weather for this point in February to be fairly rare—about 1%, according to about 30 years of weather records. That said, it’s been a productive season for Old Man Winter, who ushered in the New Year with a polar vortex that swept coastal rains and snow across the Pacific Northwest and blew subzero temperatures and blizzard conditions across the Great Lakes and the Mid-Atlantic states.
Unfortunately, that’s not all. Severe storms are expected on the southern side of the system—the Gulf states from east Texas to west Florida, where temperatures are slightly warmer. Thunderstorms are expected across the region and as far north as Oklahoma in the west to West Virginia in the east, though the most severe storms will be concentrated in southern Alabama and Mississippi. And as we reported yesterday, there is a moderate risk of excessive rainfall in Southern California through Thursday and a slight risk of it in Northern and Central California today. Given the recent wildfires in California, the deluge of rain creates a serious risk of mudslides.
On the bright side, New Mexico is the only state without any weather warnings or advisories, aside from South Carolina and Florida, which have coastal advisories in place. If you’re in Albuquerque, stay put!
