Two powerful storms are expected to hit the U.S. this week, threatening the nation’s holiday travel plans.

“A very active weather pattern will dominate the Thanksgiving week travel period, leading to potential travel impacts across large portions of the Central and Western U.S.,” the National Weather Service (NWS) said in a statement Tuesday.

The statement continued:

The lead storm developing across the Southern to Central Plains Tuesday will deepen as it pushes northeast into the Upper Mississippi Valley/Upper Great Lakes Wednesday and across northern New England by early Thursday. A broad region of heavy snow potential with this storm will stretch from the Central Plains into the Upper Mississippi Valley Tuesday, across the Upper Great Lakes on Wednesday and into northern Maine by Thursday. Snow totals across much of these regions expected to be in the 8-12″+ range.

In addition to the heavy snow potential with the lead storm, rain and thunderstorms are likely Tuesday evening/night along the trailing cold front sweeping eastward across the Mid to Lower Mississippi Valley, Ohio Valley and Tennessee Valley. Some of these storms may produce severe weather across the Middle to Lower Mississippi Valley, with a slight to enhanced risk of severe weather denoted in the latest Storm Prediction Center’s Convective Outlook for the day 1 period.

“The first storm system is expected to dump heavy snow in parts of the Midwest on Tuesday and bring gusty winds to the East Coast by Thursday — just in time for the Macy’s Thanksgiving Day Parade,” according to a Fox News report.

A second storm moving inward on the West Coast may hit parts of California and Oregon with heavy snow and high winds, resulting in treacherous driving conditions.

“In Southern California, a flash flood watch has been issued from San Diego to Santa Clarita, where 2 to 3 inches of rain are expected from Wednesday through Friday,” the Fox News report said.

Tuesday afternoon, the NWS tweeted a storm warning for residents on the West Coast.

With an estimated 55 million people traveling this week for the holiday, the NWS urged individuals to check the forecast before leaving and to be prepared for any potentially dangerous weather conditions.