Increased flow from river tributaries and moderate rains, locally and farther north, has caused the Lower Mississippi River Forecast Center to push back its Vicksburg crest forecast another week and raise it to flood stage.

The new forecast has the river cresting on Thursday, May 27, at 43 feet, official flood stage at Vicksburg. The forecast crest has been nudged up and pushed back a handful of times over the past week. Before Thursday’s change, the forecast center was calling for a crest today of 42.7 feet.

“It’s going to be a pretty slow rise to flood stage at Vicksburg, only going up a 10th of an inch or so every couple of days,” said LMRFC hydrologist Daniel Pearce. “It will probably stay around 43 feet for a couple of days and then very slowly start to fall.”

As of this morning, the river was running at 42.7 feet, a rise of 0.1 foot over the past 24 hours.

While a flood stage crest will have limited impacts in the city and county, it will “prolong the agony” in the Yazoo Backwater Area, said U.S. Army Corps of Engineers Water Division Technician Waylon Hill.

The Corps had hoped to re-open the gates of Steele Bayou — the lone drainage point for the 4,093 square miles of forest and farmland in the southernmost tip of the Mississippi Delta known as the Yazoo Backwater Area — by the first week of June. The gates, about 25 miles north of Vicksburg off Mississippi 465, were forced closed by the rising river on May 6. Hill said the new forecast probably will push the re-open date back another week or more.

“It might be the second week in June now before we can open the gates,” said Hill. “Of course, that puts us at the mercy of the rain.”

Steele Bayou was holding more than 6 feet of water out of the backwater area this morning, with the riverside water stage measuring 90.5 feet and the landside 84.3 feet — both rises of 0.2 feet over the past 24 hours. With normal rainfall, the Corps expects the water stage to reach about 88 feet in the backwater area. Low-lying crops begin to go under-water at 86 feet.

The city’s rain gauges collected between a quarter and a half inch of rainfall at various locations across Vicksburg Thursday. The National Weather Service is calling for a 30 percent chance of showers and thunderstorms today, mainly before 1 p.m. The weekend forecast looks mostly sunny locally, as does the beginning of next week.

In the county, Chickasaw, Thompson Lake and Long Lake roads are all closed, said Road Manager Richard Winans. The nearby Kings Point Ferry, which normally would be shuttling a few private landowners across the Yazoo Diversion Canal each day this time of year, has also been shuttered.

“There will be a couple more secondary roads that will probably go under, depending on any rainfall we get,” said Winans this morning.

Mississippi 465, which leads to the Eagle Lake community from U.S. 61 North, and LeTourneau Road in southern Vicksburg will not go under water unless the river nears 46 feet. No roads have been closed in the city.

Now at a slow rise, the river had been jumping up by one to two feet a day before this week. Two weeks ago, the river was nearly 10 feet lower than it is today. This is the third significant rise this spring. In mid-February, the river rose to an early season crest of 41 feet — which forecasters warned could signal an even greater spring rise. On April 9, the river rose again, to 40.9 feet.

When the river reaches flood stage next week, it will be the third consecutive year of spring flooding in Vicksburg — the first time that’s happened since 1996 through 1998. Last year, the river topped out at 47.5 feet on May 27, and in 2008 the river peaked at 50.9 feet on April 19 — the highest stage since 1973.

Backwater area flooding was even more significant the past two years. The backwater area water stage peaked at 93.7 feet in 2009, and in 2008 it reached 92.3 feet — marking the third and sixth worst flood events in the area since the levee system was completed in 1978. During each of those floods, the Corps estimated more than 400,000 acres of land went underwater.