Protesters block traffic during Occupy D.C.’s Wednesday march. (By Tim Craig/The Washington Post)

7:10 P.M. Update:

If you’re heading out any time tonight, be warned:It’s going to be wet and it’s going to be a slow trek. The Capital Weather Gang reports on the less-than-stellar conditions expected tonight: Waves of rain are going to pound the region over the next few hours, and the rain will be joined by sleet and snow in the coming hours.

The rough evening commute continues for travelers across the region. Backups continue on Eye Street around McPherson and Farragut squares, while Virginia Avenue is badly congested in Foggy Bottom.

The Occupy D.C. protesters are making stops at Freedom Plaza and the National Mall en route to the Supreme Court. They’ll be heading east on Pennsylvania Avenue, so avoid the stretch from 14th Street to the Capitol area.

Remember to follow @newsbysamuels for live updates from the protesters.

6:50 P.M. Update:

The marchers have left the White House and are en route to the 1400 block of Pennsylvania Avenue and, beyond that, the Supreme Court at the eastern end of the Mall. They will be heading east on Pennsylvania Avenue from 14th Street to First Street. Avoid that stretch and surrounding areas.

6:30 P.M. Update:

All Metrobus routes are running normal service in downtown Washington, according to the transit agency. Numerous bus routes were detoured or delayed due to the street closures earlier today.

6:15 P.M. Update:

Follow @drgridlock for the latest traffic updates and @newsbysamuels for news from the march.

Undeterred by dozens of arrests and persistent rain that soaked them all day, Occupy D.C. protesters opted to go ahead with plans for an evening march to the White House and Supreme Court.

The Occupy crowd held a meeting in McPherson Square shortly after 5 p.m. to discuss march plans after between 50 and 70 people were arrested earlier in the day. They decided to go ahed with plans to march, albeit an hour behind schedule.

The protesters headed to Freedom Plaza on their way to the White House. They were en route to the White House at about 6:15 p.m. They will follow that by heading to the National Mall and the Supreme Court.

The marchers will cause some delays, but it’s proving to be a slow, brutal slog for commuters across the District and beyond. Congestion stemming from numerous street closures along K Street between 14th and 16th street continued to reverberate during the beginning of the evening commute.

Traffic was backed up for blocks on K Street, and even as streets reopened the rain caused significant delays to linger. The rain is also adding to congestion across the region.

5:35 p.m. Update: Staff writer Clarence Williams reports that, according to D.C. police, 62 people were arrested at the intersections of 14th and K streets and 16th and K streets. Officer Hugh Carew told Williams that officials are still trying to sort out the charges.

4:30 p.m. Update: Metro reports that most bus routes are resuming their normal patterns, but riders should expect delays. Rain showers continue to contribute to the congestion.

4:25 p.m. Update:According to latest reports, dozens of people have now been arrested. D.C. police estimated the preliminary number between 50 and 70. According to Annie Gowen and Tim Craig’s report, many of the people were charged with “obstruction of a public highway.”

3:50 p.m. Update: Post staff writers Annie Gowen and Tim Craig report that at least 11 people have been arrested during the protests that have snarled downtown traffic. Read their complete story here. Staff writer Teresa Tomassoni is also on the scene. You can follow her tweets as well, @TTomassoni.

3:21 p.m. Update: Metro plans to detour its S1 bus route beginning at 4 p.m. Northbound buses will detour on 18th Street NW to P Street to 16th.

S2 and S4 buses will detour using 155th Street between H and Massachusetts.

2:50 p.m. Update: While the knots of protesters are gone from intersections such as K and 15th, drivers are still dealing with delays. Some of the worst congestion seems to be concentrated on streets running east-west. These include H, I, K and L. However, drivers blocking the cross-streets are causing additional problems on north-south routes. The rain, which has been heavy at times, isn’t helping.

1:35 p.m. Update:

Protesters flooded K Street around the intersection of K and 14th streets early Wednesday afternoon, with hundreds gathering amid a persistent drizzle and shutting down a stretch of downtown Washington.

At least two different groups of protesters marched across Washington in the late morning, with one group heading to the Podesta Group on G Street to demonstrate.

Marchers then headed back to K Street, right near Occupy D.C.’s McPherson Square encampment.

The throngs of demonstrators shut down 16th Street between I and L streets and K Street between 15th and 17th streets. The police reported that all westbound traffic was shut down on K Street at 14th Street.

These closures and the masses of people are also causing major delays on surrounding streets.

Numerous Metrobus routes were going to be detoured or delayed due to the road closures, according to WMATA. The transit agency recommended that riders take the Metro to Dupont Circle and board at bus stops north of Massachusetts Avenue. The DC Circulator was also delayed from having to move around the closures.

Shortly after 1:15 p.m., protesting groups began splitting up. One group is moving south on 14th Street from K Street, according to police.

Another, smaller group of protesters remained at the intersection of 14th and K street. There are currently about 20 protesters with their arms linked.

Southbound 15th Street was open or reopening by 1:30 p.m., according to the District Department of Transportation. Vermont Avenue and K Street was also reopened.

At least nine protesters have already been arrested, according to Post reporter Annie Gowen.

Original Post:

[This post has been updated]

A march through part of downtown Washington could snarl traffic about midday Wednesday, with delays potentially extending into the afternoon and evening commute.

Police said the permit for the march has been issued for the Service Employees International Union. However, Occupy D.C., on its Web site, describes Wednesday as a “Day of Action: Occupiers Unite.”

According to the union’s Web site, there are a series of “Take Back the Capitol” events this week, including showing up “at Congressional hearings and the offices of K Street lobbyists.”

Events are likely to include Occupy Chicago protesters who left the Windy City by bus Monday morning.

The march is scheduled to begin at 11 a.m. and move from Franklin Park to Farragut Park, reports the District Department of Transportation and the D.C. police. These agencies warn to expect delays around K Street between 13th and 17th streets and in surrounding areas.

The Occupy marchers plan to meet in McPherson Square at 10:30 a.m. before heading to “an undisclosed lobbying firm,” according to a post on Occupy D.C.’s site.

At noon, the Occupy protesters plan to return to McPherson Square for “an occupation block party on K Street.” They will proceed to the White House at 5 p.m., and from there they will head to the Supreme Court to protest the Citizens United ruling.

If you work or commute in any of the above areas, it’s best to plan for potential congestion stemming from these marches. Try to avoid traveling through these spots when the protesters could be marching.

Last month, Occupy D.C. protesters headed from McPherson Square to the Key Bridge. The march wound up having relatively little impact on the afternoon and evening commute, outside of causing some relatively minor back-ups in Georgetown. Earlier protests caused bigger traffic headaches. Still, with this march going through such a congested stretch of the District, it’s best to prepare for delays so you aren’t caught off-guard.