While much of the United States will be void of snow this Christmas, extremely heavy snow will fall in portions of the western U.S. while light snow is forecast for the northeast.
Heavy mountain snow and rain in the West and record warmth for the central and eastern U.S. are the focus of the short-term forecast period from Christmas through to Sunday. In the West, a series of storm systems will continue to bring heavy mountain snow, moderate lowland snow, and rain to the West Coast and the Rockies through the Holiday Weekend. Another foot of snow is likely for the Cascades in the Pacific Northwest and Sierra Nevada in California, with locally higher totals over several feet possible for northern portions of the Sierra Nevada. Totals of around 6-12″, with locally higher amounts, are also forecast for portions of the northern and central Rocky Mountains.
While heavy snow falls on portions of the West, cooler air will continue to move in across the Pacific Northwest as a series of cold fronts moves through and an upper-level trough begins to dig further south over the region. Widespread highs in the 30s are likely both Saturday and Sunday. Due to the cooler temperatures, snow levels will continue to lower to sea level, with snow forecast for both Seattle and Portland. The greatest chance of accumulation will be for Portland and the Willamette Valley in Oregon, where 1-6″ of snow is possible. Meanwhile, rain showers will continue for the West Coast and portions of the desert Southwest. A Marginal Risk of Excessive Rainfall remains in effect through Saturday morning for central Arizona where rainfall rates of around 1/2″/hour will continue to lead to the threat for flooding across burn scars.
With the wild winter weather in the forecast, the National Weather Service has issued widespread Winter Storm Warnings and Winter Weather Advisories for the mountain ranges across the West due to both the forecast heavy snow and high winds resulting in blowing snow and dangerous travel conditions.
The west doesn’t have a monopoly on the wintry weather. Winter Weather Advisories are up from north western New Jersey and northeastern Pennsylvania into eastern New York, Connecticut, Rhode Island, Massachusetts, Vermont, and parts of New Hampshire. There, light snow or a light freezing rain / drizzle mix will coat the ground with slick accumulations.
In the northeast, the National Weather Service warns: “Difficult travel conditions are possible. Slow down and use caution while traveling. Prepare for possible power outages.”