(Robert Thomson / The Washington Post)

The Metro rail system opened at 5 a.m., with the transit system aiming for normal weekday service this morning. Metrobus service has been suspended, however, owing to the conditions on the region’s roads.

Metro said it will run trains every six to 10 minutes during the morning rush. But Metro warned that snowfall of 8 inches near the electrified third rail could result in above-ground service being suspended. As a result, trains would stop servicing about half of Metro’s 86 rail stations.

In addition, even if service at these stations isn’t halted, trains may not operate as often later in the day due to the weather and predicted low ridership.

Metro had announced yesterday that MetroAccess, which serves riders with disabilities, would not operate on Thursday.

Metro suspended all bus service “until further notice,” at 3:30 a.m. Thursday due to weather and road conditions.