Winter Storm Gregory to Spread a Wintry Mess of Snow and Ice From the Northwest to the Upper Midwest and Interior Northeast

Chris Dolce and Brian Donegan
Published: January 1,2017
Winter Storm Gregory will spread snow along with some sleet and freezing rain from the Northwest to the northern Plains, Upper Midwest and interior Northeast during the first few days of 2017.
(MORE: How Winter Storms Are Named | Winter Storm Central)
This wintry mess from Gregory is due to an upper-level trough, or dip in the jet stream, that has moved southward over the West bringing cold temperatures and snowfall.

Current Conditions and Radar

Sunday morning, moderate snow from Gregory was reported in Seattle where 2.5 inches was measured at Seattle-Tacoma airport. Up to 3.5 inches of snow was measured well north of Seattle near La Conner.
(NEWS: Latest on Impacts From Gregory)

A portion of the aforementioned trough and a couple of surface low-pressure systems will then slide east early this week, spreading the snow and ice into parts of the Midwest and interior Northeast. Winds will increase across the northern Plains later Monday into early Tuesday due to one of those surface lows, making near-blizzard conditions a possibility in that region.
The National Weather Service has posted various winter storm warnings, watches and advisories across a swath from the Pacific Northwest to Montana, the Dakotas, Minnesota and northern Wisconsin.

Winter Weather Alerts

Let's break down the forecast timing and then look at how much snow to expect.
(MAPS: Weekly Planner)

Sunday-Sunday Night

• Snow continues across the Pacific Northwest, including the Spokane, Washington, and Medford, Oregon, areas.
• Snow will also spread across the interior West and into the Rockies.
• Sunday night, precipitation will spread farther east into parts of the Great Lakes region and into the Northeast ahead of this system.
• Colder air trapped near the surface may cause the precipitation to fall in the form of freezing rain in central Pennsylvania and northern Iowa.
• This may lead to slick roadways if untreated, Sunday night.

(MORE: New Year's Outlook)

Sunday Night's Forecast

Monday-Monday Night

• An area of low pressure is expected to organize in the Plains, with precipitation stretching from the northern Plains into the Upper Midwest, northern Great Lakes and New York state and northern Pennsylvania.
• Mainly snow is expected in the northern Plains, while snow, sleet or freezing rain is expected from eastern Nebraska to northern Iowa, southern Minnesota and central Wisconsin.
• The snow will be accompanied by increasing winds in the Dakotas and northern Minnesota, leading to reduced visibility and blowing/drifting snow.
• Sleet or freezing rain is expected from northern Pennsylvania and far northwestern New Jersey into southern New York and, by Monday night, parts of New England.
• Mainly rain is expected elsewhere in the mid-Mississippi Valley, Ohio Valley, southern Great Lakes and mid-Atlantic states.
• Slippery travel is again possible on any untreated surfaces.

(MORE: Five Reasons Why Freezing Rain Really Is the Worst)

Monday's Forecast

Tuesday-Tuesday Night

• Sleet and freezing rain continue in portions of northern New England. The heaviest snow is likely to be in northern Maine.
• Snow will also linger over parts of northern Minnesota, northern Wisconsin and Upper Michigan.
• Mainly rain is expected across the rest of the Northeast and into the Ohio Valley.
• Heavy lake-effect snow may develop by Tuesday night across the upper Great Lakes, possibly spreading into the lower Great Lakes snowbelts Wednesday or Wednesday night.

(MORE: January's Cold Reality Sets In Next Week)

Tuesday's Forecast

Snow and Ice Forecast

Snowfall Forecast Through Tuesday

West

• A foot or more of snow is expected in higher mountain locations from the Oregon Cascades and northern Sierra Nevada into the northern Rockies.
• Some accumulating snow will also impact lower elevation locations such as Medford, Oregon, Boise, Idaho, and Billings, Montana.

East

• A band of 5-8 inches, locally 8-12 inches, of snow is possible from North Dakota to northern Minnesota, far northern Wisconsin and Upper Michigan.
• Lighter amounts of snow are possible just south of that band from South Dakota to central Minnesota and the rest of northern Wisconsin.
• In the Northeast, northern Maine has the best chance of seeing several inches of snow, possibly exceeding 6 inches.
• Ice accumulations will mostly be minor, but could cause slick travel conditions in northern Iowa, southern Minnesota and interior portions of Pennsylvania, New York and northern New England.

MORE: Winter Storm Europa, December 2016