Winter Storm Harper is already pummeling parts of the West with heavy snow and will spread its mess of snow, ice and wind into the Plains, Midwest and Northeast into this weekend.
Harper’s heaviest snow, so far, is in the Sierra Nevada of California. Early Thursday morning, Lone Pine, California, reported 5 inches of snow had fallen in just 2 hours.
That storm will tap into cold air once it moves through the central and eastern states Friday through the weekend, delivering a widespread swath of significant snow.
Happening Now
Snow is falling in parts of the Rockies and Utah’s Wasatch as Harper is moving eastward through the West. Snow is beginning to spread into the Dakotas and Nebraska.
Snow is winding down in California’s Sierra Nevada and the through the Cascades after multiple days of heavy snow and wind.
Winter storm watches and warnings and winter weather advisories have been posted by the National Weather Service from the northern and central Plains eastward through the southern Great Lakes and into the Northeast.
Cities included in the winter storm watches or warnings include Chicago, Milwaukee, Boston, Hartford, Providence, Pittsburgh, Albany, Buffalo, Cleveland and Des Moines.
In general, locations in winter storm warnings can expect the worst conditions from this storm from Friday into the weekend.
Winter weather advisories and warnings are also posted throughout the Mountain West, which will feel the effects of Harper on Thursday.
Additional watches, warnings and advisories will be issued in the days ahead.
A Look Ahead
As Winter Storm Harper gets east of the Rockies, it will ramp up Friday into Saturday in the Plains and Midwest.
The system will generally travel from Oklahoma northeastward into the Ohio Valley and then the Northeast.
Here’s a look at Harper’s timing, but keep in mind that changes to this forecast are likely since we are still a few days away.
Forecast Timing
Prior to Harper, there will be a separate, weaker weather system that will spread light snow, sleet and freezing rain through parts of the Midwest and Northeast through Friday. This system could make for slick commutes in these areas.
(MAPS: 7-Day U.S. Rain, Snow, Ice Forecasts)
Winter Storm Harper follows that first weaker system.
Thursday
- Harper will spread snow through the Rockies and into the northern Plains Thursday evening.
- Snow will continue, but become lighter in the Sierra and Cascades, eventually tapering off overnight.
- Some freezing rain is possible late Thursday into the overnight hours from extreme southern South Dakota into western and central Nebraska. Some sleet may mix in at times.
(The green shadings depict where rain is expected. Areas that are shaded blue are expected to see snow. Purple-shaded locations may see either rain or snow. Areas in pink are expected to see sleet or freezing rain (ice). )
Friday
- Snow will continue over the Rockies, including down to valley floors.
- Snow, possibly heavy, will continue to spread into the Plains states.
- Blowing and drifting snow is likely in parts of the Midwest.
- Evening commutes may be impacted by snow in some cities, including Kansas City, Omaha, Des Moines, Sioux Falls and Milwaukee.
- A sharp cut off in the snow is expected in southern Minnesota, and at least right now, it appears that Minneapolis will stay out of the most impactful snow.
- Friday night, snow should spread east into the lower Great Lakes, and any rain may change to snow in Kansas and in parts of Oklahoma.
- Some sleet or freezing rain may develop Friday night in parts of Missouri, southern Illinois and Indiana.
(The green shadings depict where rain is expected. Areas that are shaded blue are expected to see snow. Purple-shaded locations may see either rain or snow. Areas in pink are expected to see sleet or freezing rain (ice). )
Saturday
- A large area of snow, heavy in some areas, is expected from parts of the Midwest, spreading into the Northeast, with snow arriving in New England mainly late Saturday.
- Strong winds may accompany the snow in the Midwest, potentially leading to near-blizzard conditions in some areas.
- A band of sleet and freezing rain is possible in Kansas and Missouri eastward into Ohio, West Virginia and the mid-Atlantic states. Saturday night, some freezing rain and sleet may spread into parts of the lower Hudson Valley and southern New England.
- Precipitation may eventually change to rain along at least parts of the Interstate 95 corridor late, though the details of when and where that may happen remain uncertain.
(The green shadings depict where rain is expected. Areas that are shaded blue are expected to see snow. Purple-shaded locations may see either rain or snow. Areas in pink are expected to see sleet or freezing rain (ice). )
Sunday
- Heavy snow is expected over the interior Northeast from parts of New York state north of the Lower Hudson Valley to parts of New England.
- This snow will linger in New England Sunday night.
- Strong winds will buffet much of the East, leading to areas of blowing and drifting snow.
- Some sleet or freezing rain is possible in coastal and southern New England.
(The green shadings depict where rain is expected. Areas that are shaded blue are expected to see snow. Purple-shaded locations may see either rain or snow. Areas in pink are expected to see sleet or freezing rain (ice).)
Forecast Snow, Ice, Impact
There are still some key uncertainties in the forecasts for both snow and ice, fairly typical of any winter storm.
Keep in mind that since this is still a few days away, this forecast may change.
(MORE: Why Do Snowfall Forecasts Change as a Potential Storm Gets Closer?)
Snowfall:
- A swath from the Plains to the lower Midwest to the interior Northeast and New England is likely to pick up heavy snowfall.
- Parts of the interior Northeast and New England are likely to pick up 1-3 feet of snow.
- Snowfall amounts along the immediate Interstate 95 corridor, especially from southern New England through the New York City tri-state area, are uncertain, dependent on how quickly the changeover to rain occurs, if that occurs, and how long snow persists on Harper’s back edge.
- The amounts shown, particularly from southeastern Massachusetts to central New Jersey, may not match what you see in your front yard. Snow may fall for a period, then rain may melt that snow, then it may snow again.
- There will be areas of blowing and drifting snow, particularly in parts of the Plains.
- The combination of winds and heavy snow may lead to numerous power outages, particularly in the heaviest snow swath in the interior Northeast.
- For some parts of Harper’s swath, it could be the worst winter storm in a decade, according to NWS Cleveland.
(This is a preliminary look at snowfall totals possible with Winter Storm Harper. Particularly in the East, these totals may shift a bit as we get closer to the event.)
(MORE: Why Do Snowfall Forecasts Change as a Potential Storm Gets Closer?)
Ice:
- A rather expansive swath from the Plains to the Ohio Valley to New England may see accumulating freezing rain and/or sleet.
- Ice accumulations sufficient to slicken most roads, at least for a time, are most likely from the Ohio Valley to the Appalachians, mid-Atlantic states and southern and coastal New England.
- The combination of strong winds and accumulating ice (in addition to snow) on trees and powerlines may lead to numerous power outages and tree damage in the interior Northeast, and parts of the Ohio Valley. Worsening the power outage threat is that bitter cold will sweep in after Harper departs.
(Ice accumulations of at least 0.10 inch typically make most roads, especially untreated bridges and overpasses, hazardous. This current outlook only goes through Sunday evening. Additional ice accumulation is possible in parts of New England Sunday, beyond the time of this outlook.)
Travel impact:
- If you have travel plans this weekend in the affected areas of the Midwest and Northeast, you should consider changing those plans.
- Road travel is likely to become difficult, if not impossible, in parts of the Midwest and Northeast Saturday into Sunday.
- Accumulations of sleet and ice from the Ohio Valley and mid-Atlantic states into parts of New England may also lead to dangerous travel, particularly over bridges and overpasses.
- Even if snowfall totals are lower, expect major flight delays and possibly some cancellations this weekend at the major Northeast hubs, including Boston-Logan, Newark, JFK, LaGuardia, Philadelphia, Dulles and Reagan National airports.
- Some significant delays are also possible Saturday at Chicago O’Hare, Kansas City International Airport and other airports in the Midwest, Ohio Valley and interior Northeast if heavy snow reduces visibilities and requires clearing of runways.
Check back with us at weather.com for updates on Winter Storm Harper.
Winter Storm Harper Archive
Harper is evolving from a large low pressure system just of the Pacific Northwest coast. Energy from that system spread high elevation snow to the Sierra and rainfall to much of California on Jan. 16-17.
The snow closed Interstate 80 through the Sierra at times as high winds gusted over the mountains and crashes occurred in Donner Pass.
https://twitter.com/CHP_Truckee/status/1085684959132536832
Harper spread some snow through the Rockies and Wasatch on Jan. 17 while continuing to provide snow in the Sierra and Cascades.
Here are selected snowfall totals since 4 a.m. PST Wednesday (Jan. 16). Some totals may include snow from other disturbances, especially on the West Coast. Only totals greater than 6 inches are included.
- California: up to 36 inches in June Mountain Ski Area; 28 inches at Squaw Valley
- Idaho: 10 inches near Atlanta and Hailey
- Nevada: 24 inches at Mount Rose Ski Area
- Oregon: 6 inches near Trout Lake
Winds gusted over 130 mph in parts of the northern and central Sierra late Jan. 16 into early in the 17th. Mammoth Mountain even gusted to 164 mph with a sustained wind of 132 mph early on Jan. 17.