The following is provided by DC Severe Winter Weather:

[UPDATE]

1/22, 3:08 PM:

We’ve had to revise our snow map to reflect higher totals that are now expected. It seems unreal, but this storm cannot be taken lightly. Heavy snow w/ winds and power outages. Here’s our final map. Snow will begin this afternoon. Please stay safe, and once the snow starts, be prepared to stay where you are for the whole weekend.

[Original Post]

1/21, 8:00 PM:

We are officially 24 hours out from what has the potential to be one of the top 5 snowstorms to ever impact the DC area. This textbook storm is primed to drop upwards of 2 feet of snow across most of our readership. Here is our full forecast and a closer look at the timing and impacts of this large storm:DC and surrounding counties to the North and East are under a blizzard warning for heavy snow and high winds that will make travel near impossible. For our counties to the west, a Winter Storm Warning is in place for over 2 feet of snow. Our recommendation is that you start preparations NOW. Make sure you have food to last the weekend and a safe place to stay, as roads will be terrible to drive on, and there may be a lot of power outages across the region.

We expect a complete travel shutdown, with exception of the underground portions of the DC Metro Rail. We expect this to be an all snowfall event for those along and west of Interstate 95. Once you go further east, mixing becomes a possible issue as the storm winds up right off the coast. During the day Saturday, mixing in eastern Maryland and especially near the coast may bring down totals, which is reflected in our revised snow map below. Our new map has upped totals to include a larger portion of the region in the 18-24″ zone, and we expect isolated spots to reach higher amounts. Where the good banding sets up will determine who sees more than 2 feet of snow.

So what should you expect, and when should you expect it? Here is a look at the general timeline of the storm as we are expecting it. Some small details could still change.Friday,1 p.m. to 5 p.m. : Snow begins to move in from the South west, with only light accumulations to start. Temperatures will be right around freezing.

Friday night, 5 p.m. to 10 p.m. : Snow continues to fall, becoming moderate as the night goes on. Expect a few more inches of accumulation before the late night hours.

10 p.m. Friday to 8 a.m. Saturday morning: Snow becomes very heavy and winds begin to gust. Expect to wake up to about a foot of snow on the ground.

Saturday, 8 a.m. to 6 p.m. : Heavy snow continues, and blizzard conditions may be present. Reduced visibility and about another 10 inches of snow accumulation.

Saturday night, 6 p.m – early morning: Snow continues falling at a lighter rate until the early morning hours, tapering off shortly after daybreak.

We will continue to update our forecast as needed. stay tuned to DC Severe Winter Weather.