A major snowstorm having the potential to disrupt or even temporarily crippletravel will streak west-to-east across the nation during the early and middleof next week.The instigating low pressure, arctic cold to its north and a source of moistureto its south, will track from northern California to Colorado on Monday andTuesday. At this time, snow impacts will be greatest from the central andsouthern Sierra Nevada east to the southern Rockies including a swathe on theIntermountain. Windswept snow, some heavy, could halt travel on major highwayssuch as I-15, I-70 and I-80.

Soaking rain pelting Southern California will become heavy snow over some ofthe high deserts farther east. Rare heavy snow could cover Las Vegas, forinstance.

Snow will continue streaking eastward over the central Great Plains to theGreat Lakes on Tuesday and Tuesday night. Powerful, numbingly cold windstogether with substantial snowfall could whip up a blizzard on the open plainsof Nebraska, Iowa, northern Missouri, northern Kansas, northeastern Coloradoand southeastern Wyoming. Here again, cross-country traffic could be halted ordrastically slowed in the nation's heartland.

Farther east, snow will invade the interior Northeast by Wednesday as soakingrain hits the eastern big cities. Travel could be disrupted in parts of NewEngland, New York state and Pennsylvania.

Story By AccuWeather.com Meteorologists Jim Andrews and Meghan Evans.