On Tuesday, the Northwest US will receive 12-inch snow from the heavy snowfall, while the South US will experience a cross-country storm that will bring a string of tornadoes, damaging winds, and large hail.

Northwest US

According to a tweet from the National Weather Service office in Spokane, Washington, a winter storm watch has been issued for late Tuesday night into late Wednesday evening.

The weather advisory was prompted by expected heavy snow in the northern region of Spokane, where total snow accumulations will range between 10 and 16 inches. South of Spokane, there will be total snow accumulations of 5 to 9 inches. Meanwhile, along the east side of SR-195, including US-95, total snowfall of 4 to 7 inches is possible.

The advisory includes portions of North Idaho, as well as some parts of Northeast and Southeast Washington.

Travel during this time may be extremely challenging or impossible, and Wednesday morning, as well as evening commutes, will be severely impacted, according to the NWS.

Before the heavy snow that is expected to arrive Tuesday night and continue into Wednesday, there will also be some sporadic light snowfall during the day.

In other areas, according to ABC News, In the next two days, between 6 and 12 inches of snow are predicted to fall in Denver, Colorado; Salt Lake City, Utah; and Casper, Wyoming.

South US

On Monday night into Tuesday morning, a cross-country storm moving east is predicted to bring heavy snow to areas from Nebraska to Michigan. Due to the impending storm, 18 states are on high alert for snow and strong winds.

Parts of the South US may experience tornadoes Tuesday afternoon and into the evening due to warm, moist air.

Tuesday evening, Greenville, Jackson, and Monroe, Mississippi, as well as Memphis and Nashville, Tennessee, could also experience strong, long-tracked tornadoes due to the storm system.

In addition to tornadoes, the Gulf Coast states and the lower Mississippi River Valley could experience damaging winds that exceed 60 mph and large hail.

According to the NWS, in Central Mississippi, Northeastern Louisiana, and extreme Southeastern Arkansas, several tornadoes are expected, along with isolated damaging winds. There will also be a few intense, scattered large hailstones, some as big as a baseball.

Read also: Significant Severe Weather Event to Slam South US with Multiple Thunderstorms, Tornadoes 

Due to the possibility of severe storms on Tuesday night from New Orleans to Nashville, about 15 million Americans in the South will continue to be on high alert, ABC News reports.

According to the Storm Prediction Center, tornadoes, very large hail, and extremely damaging wind gusts are highly probable across the lower to middle Mississippi Valley area into the middle and southern United States today, particularly from the northeastern Louisiana area into central Mississippi. This afternoon and into the early hours of tomorrow, some of these tornadoes will be powerful and intense.

SPC Day 1 Categorical Outlook shows that areas of Mississippi are at moderate risk of severe thunderstorms. This area in the center of the outlook includes Jackson, Meridian, Vicksburg, Clinton, and Pearl.

On the outermost part of the outlook, where there is a marginal risk of thunderstorms, areas include Houston, Texas; Indianapolis, Indiana; St. Louis, Missouri; Cincinnati, Ohio; and Louisville, Kentucky.

Related article: Severe Weather with Thunderstorms and High Winds Could Affect Over 30 Million People in South-Central U.S; Forecasts Monitor Potential Tornadoes