As the rain continues to fall the Mississippi River continues to rise.

Resident hydrologist Jessica Brooks of the National Weather Service, Davenport, issued a report Friday indicating that there is high confidence the Mississippi River at Lock and Dam 15, Rock Island, will reach 20 feet.

The most likely crest range is 20.5 feet, for which there is high confidence, all the way to 23 feet, for which there is a low confidence at this point.

The timing of the crest is between May 31 and June 6.

The crests and timing is dependent on which tributary rivers have the higher flows into the Mississippi River, Brooks said in her statement.

Heavy rainfall was expected through 7 a.m. today (Saturday) as a line of storms, one of which produced a tornado over Iowa City, moved through the region.

Meteorologist Tim Gross said that storms were expected to develop over the Quad-City Metropolitan area about midnight and that from midnight to 7 a.m. Saturday the forecast called for anywhere from a half-inch to 1 inch of rain in Eastern Iowa and northwestern Illinois.

Locally higher amounts are likely in areas over which thunderstorms develop.

The active weather pattern with rain and thunderstorms is expected to continue through Tuesday.

The active weather pattern also hit other parts of the country. The bodies of a man and a woman were discovered Friday in a submerged vehicle near the Mississippi River in Missouri, bringing the death toll to nine from storms that have ravaged the central U.S. this week and threaten major flooding through the holiday weekend.

John Reinhardt, 20, and Caitlin Frangel, 19, both of Hazelwood, Missouri, were reported missing May 15. Their bodies were found around 4 a.m. on a flooded rural road that runs along the river at Portage Des Sioux, about 40 miles north of St. Louis.

Missouri State Highway Patrol Trooper Dallas Thompson said an autopsy determined they both drowned.

"We believe they went into it in the dark, not knowing the roadway was flooded, and they were unable to get out," Thompson said.

Heavy rain in recent weeks has spurred major flooding in several states. Flooding along the Arkansas River will threaten communities from Tulsa into western Arkansas through at least the holiday weekend, officials said Friday, as water released from an Oklahoma dam combines with additional rain in the forecast.

To control flooding in Tulsa, the U.S. Army Corps of Engineers on Friday began increasing the amount of water being released into the river from the Keystone Dam northwest of the city of about 400,000.

"The dam is doing what it is supposed to do. It has maintained the flood to a manageable level," U.S. Sen. James Lankford, R-Oklahoma, said following an aerial tour of the region.

The river in Tulsa was just above 22 feet Friday, four feet above flood stage, and was expected to remain at that level through Tuesday. Riverside residents were urged to leave their homes and at least one oil refinery suspended operations.

"The most disturbing thing that I've heard in the last 24 hours from our first responders are reports of parents letting their kids play in the river," said Tulsa Mayor G.T. Bynum. "If you're a parent that's letting your kid play in this river right now, you ought to be ashamed of yourself."

The Associated Press contributed to this story.

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