(This forecast, first posted on Wednesday afternoon, was updated Thursday morning.)

For the 40,000-plus Washingtonians and others who will pack into Nationals Park on Friday night for the first World Series game in the District since 1933, there are no weather worries. But there is a slight chance of a shower or two for Saturday night’s World Series game, and showers are likely Sunday morning, coinciding with the Marine Corps Marathon.

If a third game at Nationals Park is necessary Sunday night, it looks as though rain should end before the game. This is a change from our earlier forecast, which called for showers.

Forecasts in brief

  • Game 3 at Nationals Park, Friday, 8:07 p.m.: First-pitch temperature: Near 60 degrees. Partly cloudy skies with temperatures falling into mid-50s. Chance of rain: 10 percent
  • Game 4 at Nationals Park, Saturday, 8:07 p.m.: First-pitch temperature: 58 to 60 degrees. Cloudy with a shower or two possible. Temperatures fall off only a couple of degrees, toward the mid-50s. Chance of rain: 30 percent. Chance of rain delay: 15 percent. Chance of postponement: 5 percent.
  • Marine Corps Marathon, Sunday, 7:55 a.m.: Temperatures in the mid-50s to start race. Cloudy, with intermittent showers likely, and temperature rising into the low 60s by mid- to late morning. Chance of rain: 70 percent.
  • Game 5 at Nationals Park, Sunday, 8:07 p.m. (if necessary): First-pitch temperature: 62 to 64 degrees. Decreasing clouds, with temperatures falling to near 60. Chance of rain: 15 percent. Chance of rain delay: 10 percent. Chance of postponement: 5 percent.

Forecast discussion

A storm system will organize in the South on Saturday, lifting north toward the eastern Great Lakes that night. As it moves north, it will push a warm front through the Washington region, most probably on Saturday evening, introducing a small chance of showers.

The exact timing for the onset of any showers is still uncertain, and they may end up mostly brushing areas west of Washington. That said, we can’t rule out a passing shower or two during Game 4 of the World Series. The chance of a rain delay is small and postponement remote.

Shower chances will increase overnight Saturday through Sunday morning, affecting the Marine Corps Marathon, but we do not expect a washout. Temperatures will turn rather mild, rising into the 60s on Sunday, thanks to winds from the south in the warm front’s wake.

On Sunday afternoon, a cold front will sweep across the region, probably producing a closing round of showers. Once that front exits, rain chances diminish and Game 5 of the World Series, if necessary, should be dry.