Potential Bomb Cyclone, Midwest Blizzard Ahead

W​inter Storm Elliott is tracking eastward toward the Plains, Midwest and Great Lakes, where it will produce snow and high winds, including blizzard conditions in spots, as it potentially grows in a bomb cyclone. Elliott will also bring strong winds and a possible flash freeze to parts of the Midwest, East and South.

(​MORE: Brutally Cold Air Arrives With Elliott)​

H​ere’s a look at where the storm is now and what’s to come.

H​appening Now

E​lliott’s snowfall is mostly over the Northern Rockies and adjacent parts of the Plains right now.

T​he storm brought several inches of snow to areas near and north of Seattle on Tuesday.

W​inter storm alerts, including watches, warnings and advisories, have already been issued by the National Weather Service ahead of this storm. Among the cities included are Buffalo, Chicago, Cleveland, Detroit, Indianapolis, Kansas City, Milwaukee, Minneapolis-St. Paul, Omaha and St. Louis.

B​lizzard warnings have been issued for parts of the upper Midwest, as well, illustrated by the pink polygons in the map below. Additional blizzard warnings could be issued later Wednesday or Thursday.

T​ravel should be avoided in many of these areas since it could become difficult or impossible. That’s not just because of the snow, but also strong winds and extreme cold.

Below, we’ll step you through the timing, snowfall forecast, wind forecast, and other impacts from this storm, then we’ll provide perspective on bomb cyclones and how this storm lines up with other December and all-time Great Lakes storms.

F​orecast Timing

Through W​ednesday Night

The storm will spread into the Plains as the powerful arctic cold front plunges southward. Snow could be heavy, accompanied by strong winds in parts of the central Plains and upper Midwest. Travel will become hazardous Wednesday night in the areas shaded in the teal colors below.

I​n the East, some light sleet, freezing rain or snow could develop at night from parts of western North Carolina to western Virginia and eastern West Virginia.

Thursday

The storm will intensify in the Midwest with areas of snow and rain changing quickly to snow as the arctic front races through. Strong winds will spread from the Plains to the Midwest and South. Expect dangerous travel conditions from the central Plains to the upper Mississippi Valley and western Great Lakes, with blizzard conditions in some areas.

I​n the interior Northeast, freezing rain, sleet and snow early in the day will transition to rain in most areas by Thursday evening, with the exception of northern New England and upstate New York. Rain is expected along the Interstate 95 corridor.

Friday

The storm will reach its peak intensity with high winds, heavy snow and potential blizzard conditions in parts of the Great Lakes, from eastern Wisconsin and far northeast Illinois to parts of Michigan, northern Indiana, northern Ohio, western Pennsylvania and western New York.

A​ny rain or rain changing to snow in the Northeast will be followed by bitterly cold air that could result a flash freeze, making for icy conditions in spots.

H​igh winds are also expected over much of the East as far south as Georgia and the Carolinas.

S​aturday

B​y Saturday, the storm will move away into eastern Canada, but strong winds will likely linger in much of the Great Lakes and upper Mississippi Valley. Those winds blowing over the Great Lakes could produce bands of heavy lake-effect snow that could last into Christmas Day in the eastern Great Lakes.

Also, lingering areas of blowing and drifting snow are expected outside the lake snowbelts in the Midwest where snow fell the previous few days.

H​ow Much Snow?

P​lains, Midwest, Great Lakes

More than a foot of snow is likely in the western Great Lakes snowbelts, where winds blowing over the lakes may enhance snowfall downwind of lakes Superior and Michigan over the Upper Peninsula and western Lower Michigan.

Farther south, a widespread area from the central Plains to the mid-Mississippi and Ohio valleys has a chance of at least a few inches of snow. And at least light snow totals might be enough to make roads slick as far south as parts of Oklahoma, northern Arkansas and Tennessee.

N​ortheast

I​n the interior Northeast, snowfall totals generally less than 6 inches are expected, with some accumulation possible Thursday before precipitation changes to rain, then again after the cold front swings through Friday.

Heavy snow is also expected in the eastern Great Lakes this weekend, with some one-foot totals possible in the Lake Erie and Ontario snowbelts of northeast Ohio, northwest Pennsylvania, western New York and upstate New York.

High W​ind Threat

High winds will be the most widespread impact from Elliott.

Winds will increase in the Plains beginning Wednesday night into Thursday, b​ut the strongest winds from this storm are expected Thursday night through Friday into early Saturday in the Midwest and along the East Coast from New England to Georgia Friday.

T​hese winds will be capable of downing tree limbs and knocking out power, particularly where they combine with snow accumulations weighing down trees and power lines in the Midwest and East. Plan ahead now for the potential for power outages in cold weather if you live in these areas.

Also, keep in mind e​ven areas of lower snowfall totals may see dangerous reductions in visibility due to strong winds combined with snow.

O​ther Threats

There are two other things we could see with this storm that could be dangerous for your drive.

F​irst, as the arctic cold front sweeps through the Plains, Midwest and East, snow squalls could develop.

These are bursts of snow, but they’re brief, typically lasting less than an hour. The reason they’re dangerous is they can quickly lower visibility and coat roads in a thin film of snow, making them slippery.

M​ulti-vehicle accidents can and do occur within these snow squalls, particularly on major freeways with more traffic. Keep that in mind, even if your area of the Midwest and East does not have heavy accumulations of snow in the forecast. It could instead come down in these short-lived bursts.

S​econdly, there’s the potential for a flash freeze. T​his occurs when rain soaks pavement, then is followed quickly by an arctic cold front that ushers in subfreezing air.

That fast-arriving cold air would then turn any lingering water on untreated roads into patches of ice, making travel slippery and dangerous, particularly on bridges and overpasses.

T​his is certainly possible in parts of the Ohio Valley and East ahead of the cold front Thursday into Friday.

(​MAPS: 10-Day U.S. Forecast Highs/Lows)

B​omb Cyclone Perspective

We mentioned earlier that this winter storm could become a bomb cyclone.

A​s a rule of thumb, meteorologists refer to a strengthening low as “bombing out” or undergoing bombogenesis if its minimum surface pressure drops by at least 24 millibars in 24 hours or less, though that criteria also depends on a storm’s latitude.

Meteorologists frequently discuss pressure in terms of millibars, rather than inches of mercury.

The reason this all matters beyond just a geeky statistic is the lower the pressure in a storm, the more intense it is. And the greater difference in pressure over an area, the stronger the winds.

W​inter Storm Elliott has the potential to plunge to a pressure that could threaten December low-pressure records in the Great Lakes, according to data compiled by NOAA Weather Prediction Center meteorologist David Roth.

F​or now, the latest ensemble model forecasts do not bring Elliott’s low to the level of what is considered the all-time low-pressure record – the so-called “Cleveland Superbomb” of late January 1978.

Nevertheless, this combination of wind, snow, cold, snow squalls and flash freezes will be a travel headache.

If you reside or have pre-Christmas travel plans in these areas, monitor the forecast closely and be prepared to make alternate travel arrangements. C​heck back with us at weather.com for important forecast updates in the days ahead.

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