A storm forecast to roll ashore in the Pacific Northwest Saturday will spread a swath of snow, rain, thunderstorms and wind across a large part of the nation next week.
The storm will be strong enough at times to cause travel disruptions, flooding and sporadic power outages from wind, rain, heavy snow and thunderstorms.
The northern Cascades and northern Rockies will be the first to get snow from the storm, where over a foot can accumulate in the high country over the weekend. The snow can dip as low as Snoqualmie Pass on I-90 Saturday night into Sunday.
During Sunday, the storm will emerge east of the Rockies. By then, it will throw snow and gusty wind over the Plains of Montana and North Dakota with portions of I-94 being affected. Local whiteout conditions are possible at times.
The worst of the storm will stay north of Denver as discussed on AccuWeather.com earlier this week.
Sunday night and Monday, the storm will begin to focus over the Midwest. Windblown snow is possible over portions of Minnesota, Wisconsin and the Upper Peninsula of Michigan. Meanwhile, rain and thunderstorms will be gathering farther south over the Ohio and lower Mississippi valleys.
The snow can be intense in some areas across the north, while the storms and downpours can be quite heavy farther south. The snow across the north could result in significant travel issues; the rain in the south could be heavy enough to cause incidents of flooding.
The track of the storm will determine whether or not heavy snow swings as far south as Chicago and Detroit. Minneapolis appears to be in line for a heavy snowfall.
After the storm reaches the Midwest, it may split into two parts Monday night and Tuesday with one center swinging toward the eastern Great Lakes and a new center developing near or east of the central Appalachians.
At this point, a second area of drenching rain is possible over portions of the mid-Atlantic Tuesday, spreading into southeastern New England. For all intents and purposes, it appears this storm will be a rain producer for much of the I-95 mid-Atlantic. However, low visibility and low ceilings, combined with locally gusty wind, could lead to flight delays.
Showers and thunderstorms are likely to affect the Southeast, including areas in need of rain from South Carolina to northern Florida. There is a possibility that some of the storms will become severe enough to cause damage, however.
Exactly how that second, new low pressure area tracks and strengthens will determine the extent of snow from the central Appalachians to interior and northern New England.
The greatest potential for heavy snow exists from parts of central and northern Pennsylvania to upstate New York, northern New England and neighboring Canada. However, depending on how much warm air is circulating around the storm (and there is likely to be a strong circulation with a great deal of wind), the area of snow could be smaller than this or be mixed with rain for a time over a large part of the same area.
More Problems Likely with Next Week's Storm
Because of snowfall over the winter and recent rain, there is the risk of flooding problems with the storm over the Northeast, in particular over New England. Some streams and rivers may rise to bank full. Unprotected areas prone to flooding in the spring will want to monitor this storm.
As far as coastal flooding and beach erosion are concerned, with the track of the secondary storm anticipated, the greatest risk is for New England but may not be limited to eastern Massachusetts. Southeast winds could drive some water toward Long Island, the South Coast of New England and farther north along the New England coast. Fortunately, the astronomical impact will be minimal with the moon near the first quarter stage around the time of the storm.
As previously stated, the storm will generate a significant amount of wind. Wind on the back side is likely to be greater for most areas than on the front side of the storm, especially from the Upper Midwest and Great Lakes to the Ohio Valley, Southeast and mid-Atlantic, where flight delays are possible Tuesday night and Wednesday. This includes Chicago, Detroit, St. Louis, Cincinnati, Atlanta, Pittsburgh, Washington, D.C., Philadelphia, New York City and Boston.
It is also possible the winds could be strong enough to cause sporadic power outages in these areas and on the front side of the storm in portions of New England, and in general in the heavy, wet snow areas of the interior Northeast.
The storm system will create another big southward dip in the jet stream over the northeastern part of the nation, reinforcing cold air and favoring snow showers in a number of locations for the rest of next week.