Last Updated: Wednesday, December 21, 2016, 1:42 PM EST
Travel weather looks good for Thursday over most of the country. But there is trouble brewing in the Pacific for the weekend.
- Klystron 9 | 7-Day forecast | Tampa Bay-area temperatures | Travel weather
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On Thursday, an upper low will move into the southwestern U.S., bringing heavy showers and mountain snow. The main Pacific storm moves into the west on Friday with rain and snow increasing over the Pacific Northwest.
Some snow and ice re-develops in the Midwest. Most of the eastern U.S. is mild and dry.
The weather gets worse on Saturday over much of the western U.S. with heavy snow and windy conditions developing as a strong low moves into the Central Plains. This will bring strong winds and blowing snow, possible blizzard conditions, to the Front range of the Rockies and into the High Plains.
Further east, it will be a risk of freezing rain as the warmer air overruns the colder air. As the low strengthens and moves east, it will bring warmer, moist air up through the Mississippi Valley. This could produce a large area of rain, not snow, in the Midwest and further south into the Mississippi Valley and Southern Plains.
Closer to the Gulf Coast, there could be enough moisture available for thunderstorms. The warmth on the eastern side of this storm will warm up the East Coast from Florida northward.
Places like New York City and Washington DC could have Christmas morning lows above freezing.