UNITED STATES - This setup could add extra friction to an already high-volume travel week. According to AccuWeather meteorologists, a developing storm sliding out of the Southwest is gearing up to stretch across the eastern two-thirds of the country just as millions hit the road.

It starts out west. Heavy rain and mountain snow hit California first, then roll into Arizona, New Mexico, and Colorado through the weekend. Most of the early weekend drivers will deal with wet roads rather than anything frozen, but even light showers can slow things down when everyone’s trying to get a head start.

By Sunday into Monday, the system taps into Gulf moisture and starts throwing downpours and gusty thunderstorms through Texas and nearby states. That’s when some of the big southern hubs could feel it.

The storm pushes into the Mississippi Valley on Tuesday, and depending on its exact track, we could see widespread rain from the Midwest into the Ohio Valley and beyond. In the far north, a stripe of wintry mix tries to sneak in across the Plains and upper Midwest as colder air drops down behind the system.

Wednesday is already one of the busiest travel days of the year, and even a few hours of rain or reduced visibility is enough to set off a domino effect from the Ohio Valley to the Northeast. If the storm slows down or speeds up those details will matter for both drivers and flyers from D.C. to Boston.

Behind the system, colder air sweeps in with blustery conditions and lake-effect snow around the Great Lakes. Right now, meteorologists say the strongest gusts likely hold off until later in the day, but a faster-moving front could change that.

Meanwhile, the Southeast watches for thunderstorms on Wednesday, and Florida might see some timing-dependent showers between Wednesday and Thursday. Out west, most areas stay dry, though parts of the Northwest pick up off-and-on showers tied to coastal systems.

In short, there's expected to be a long, sprawling storm with a lot of moving parts. But with careful timing, there’s still room for smooth trips if you stay ahead of the forecast.

For the latest travel-week updates and storm timing, be sure to check ANUK.