Editor's note: This story was last updated Friday night.

will continue to bring snow, ice and wind from the South to the East Coast through Saturday night. Here are five things you need to know about the storm today.

1.) Blizzard Warnings Now Include New York City and Philadelphia

Winter Storm Jonas Alerts

The National Weather Service expanded blizzard warnings Friday morning to include Philadelphia and New York City. This is in addition to the blizzard warnings that were already in effect for Washington, D.C. and Baltimore.

Blizzard warnings now encompass a swath from northern Virginia and Maryland to northern Delaware, southeast Pennsylvania, portions of New Jersey, Long Island and southern Connecticut.

2.) Heaviest Snow Area Locking In

Snowfall Forecast

(Forecast snowfall accumulations for Jonas.)

Confidence is now high that a swath of West Virginia, Virginia, Maryland and the District of Columbia will see the highest snow accumulations. This includes parts of the Baltimore and Washington D.C. metro areas. Some isolated locations in this swath should see over 2 feet of total snow through Sunday morning.

In addition, a swath from eastern Kentucky to northwest North Carolina to far southern Pennsylvania and parts of New Jersey may pick up a foot of snow or more.

Needless to say, road and air travel will be crippled in these areas this weekend.

From Pennsylvania to southern New England, there may be a wide range of snowfall totals across a short north-south distance. The heaviest totals are mostly likely in the southern end of this area, with lighter amounts farther north.

You can find our latest forecast thinking on snowfall amounts for Jonas .

3.) Tens of Millions Will Be Impacted

Winter Storm Jonas Alerts

Jonas is not just an impactful storm for the East Coast. It will also bring significant snow and ice to parts of the Ohio Valley and South through much of Friday.

By the time Jonas exits into the Atlantic Ocean Sunday, accumulating snow will have fallen from the central Plains into the Ozarks, Lower Mississippi Valley, Mid-South, Tennessee Valley, Ohio Valley, Appalachians, Mid-Atlantic states and Northeast Seaboard.

This winter storm will also lay down corridors of significant icing in areas from Kentucky to the Carolinas.

As of Friday afternoon, just over 89 million Americans were covered by a National Weather Service blizzard, winter storm, winter weather or freezing rain alert from the lower Mississippi Valley to the Northeast. This is slightly over one-quarter of the U.S. population.

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4.) Widespread Power Outages Likely

Power Outage Potential

(Areas in the darkest purple shading are most likely to experience power outages due to snow or ice and wind from Winter Storm Jonas)

Between heavy snow, ice and high winds, Winter Storm Jonas is likely to wreak havoc on trees and power lines. The weight of potentially over 2 feet of snow in and near the central Appalachians and nation's capital is liable to down numerous tree limbs and some full trees -- some likely tumbling onto powerlines.

Even in areas with somewhat less snow accumulation, strong winds could add stress to trees and powerlines weighed down by snow anywhere from the East Coast to the Appalachians, Ohio Valley and Mid-South.

Then, you have accumulations of ice to deal with from Kentucky to the Carolinas, which would also down limbs, trees and powerlines, there.

In all, Winter Storm Jonas could knock out power to over a million customers -- some for over 24 hours. Plan now for the potential of power loss at your home.

5.) Snow/Ice Threat Affects South

Winter Alerts: South-Central

Often in forecasting, the trend is as important as any forecast made at any one time. One such trend with Winter Storm Jonas is the snow or ice line has crept a bit farther south.

Snow fell on Friday as far south as southern Alabama, the Florida panhandle and a few other locations in northern Florida. A light accumulation of snow even affected some of the northern suburbs of Atlanta.

Early Friday morning parts of central Arkansas, including around Little Rock, had seen a half foot of snow from Jonas.

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Meanwhile, to the east, freezing rain advisories and winter storm warnings were extended into parts of South Carolina, primarily for freezing rain, but also for some light snow accumulations.

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Check back with us at weather.com and The Weather Channel for the latest on Winter Storm Jonas.

Winter Storm Jonas Photos