Flood waters are moving into Memphis earlier than predicted as residents were being evacuated already on Saturday and again on Sunday. The river was surpassed 47 feet on Sunday and is expected to crest at a record 48 feet on Monday.

While it’s no surprise that the Lower Mississippi Valley is flooding, as the predictions have been coming fast and furious. However, the timing is a bit off due to the main flood gauge malfunctioning. Previously, the river was expected to crest closer to Wednesday of this week.

Memphis is on pace to see the worst flooding since 1927. Some 20,000 people may need access to shelters, according to city officials. Some eight states are predicted to feel the effects of the pressures from the Mississippi and Ohio Rivers.

Of course, last week the U.S. Army Corps of Engineers opened a hole in the levee near Cairo, Ill., to divert the rising waters. As a result, 130,000 acres of farmland were flooded. Whether or not similar tactics will be called upon again this week remains to be seen. There’s also concern whether the levees will hold.

 “Many levees will be stressed for more than a few days,” points out Aliex Sosnowski, AccuWeather.com senior meteorologist, “and in some cases to be taxed for a few weeks, raising the potential for failure.”

Record crests along the Mississippi River are possible in portions of southeastern Arkansas, Mississippi and Louisiana in the days and weeks ahead, according to the National Weather Service Lower Mississippi River Forecast Center.

There has been a break in the rainy weather in the jeopardized area as well as the northern states which feed into these rivers. However, rainfall at the start and the end of a mini-heat wave predicted for this week could only delay the rivers’ ability to recede.

Storms were forecast for the northern plains on Sunday, with the Dakotas, Nebraska and Iowa facing rain, hail and damaging winds. Rain is predicted to continue on and off as the weather systems move east throughout the week.

The water approaching from upstream, where the heaviest rains occurred during April and early May will continue to cause most of the problems and stress the river through the middle of May, Sosnowski notes.