Participants in the Twin Cities Marathon will probably be running under mostly dry skies on Sunday, despite cancellations of some related events on Saturday because of concerns about lightning.

Twin Cities in Motion, which organizes the marathon and other events, canceled the TC 10K and TC 5K and the Medtronic TC Family Events on Saturday because lightning storms were forecast for the downtown St. Paul area throughout the morning, the organization announced on its website. The Health & Fitness Expo at St. Paul RiverCentre, scheduled to run until 7 p.m. Saturday, was not affected by the cancellation.

"We're disappointed to be unable to host today's event, but safety of participants and volunteers will always be Twin Cities In Motion's primary concern," Twin Cities in Motion Executive Director Virginia Brophy Achman said in a statement. "We are excited to greet marathon and 10 mile runners at the Health & Fitness Expo today and to hold the 10 mile and marathon on Sunday."

The forecast for Sunday looks good for the marathon and the Medtronic TC 10 Mile to proceed as scheduled.

"Tomorrow it should be a dry morning and dry afternoon," Brent Hewett, meteorologist with the National Weather Service in Chanhassen, said Saturday. "There's a very slight chance of localized showers that would pop up late afternoon."

But the chance of rain is less than 20%, and any showers would affect only small areas, he said: "Most people are going to stay dry."

Temperatures are expected to be in the 60s, Hewett said, with brisk winds out of the west at 10 to 15 mph.

Twin Cities in Motion has a no-refund policy. But the organization is offering the 10K and 5K runners a $10 credit that can be used in future Twin Cities in Motion events. Registrants will receive a code for the credit and details for using it via e-mail by October 31.

Registrants for the family events will not receive a credit because of costs already incurred and because they're operated with no revenue margin as part of Twin Cities in Motion's nonprofit mission to support youth fitness.

Registrants can still pick up their participant shirt and medal at the Twin Cities in Motion office from 9 a.m. to 5 p.m. Monday through Friday the week of October 14-18.

Katy Read • 612-673-4583