(CNN) Mississippi Gov. Tate Reeves declared a state of emergency Saturday as weather and emergency management officials now anticipate the Pearl River cresting in Jackson on Monday -- about 24 hours earlier than initially projected -- after record-setting rainfall this week.
"If predictions prove accurate, the Pearl River is expected to crest on Monday, August 29th, at 36 feet," Reeves said in the declaration.
A flood stage is considered "major" at 26 feet. The current flood warning says dozens of additional streets in downtown Jackson will flood at 34 feet, with water close to entering homes in Northeast Jackson at 35.8 feet.
"The state of Mississippi is as prepared as possible for this flooding. My administration, including MEMA, is monitoring this situation closely, and actively working to respond as quickly as possible to ongoing developments with flooding," Reeves said.
Jackson Mayor Chokwe Antar Lumumba has called for voluntary evacuations in areas expected to be affected by the rising waters, saying authorities are "expecting waters to begin to impact neighborhoods as early as Sunday evening."
Lumumba and Reeves both warned residents if their homes flooded during the 2020 flooding event, there is a high likelihood it will happen again.
"Residents in those impacted areas should be ready to leave within 48 hours," Lumumba said at a news conference Saturday, but he stressed, "If you are capable of getting out now, get out now."
Several neighborhoods in northeast and downtown Jackson were flooded and the Pearl River reached its third-highest crest on record at 36.7 feet in February 2020.
Lumumba said he expects as many as 150 homes to be affected by the rising waters. He also warned residents floodwaters may remain on the ground for several days, and residents should be prepared to evacuate for up to two weeks.
State emergency management officials have already begun assessing water levels along the Pearl River and have deployed more than 100,000 sandbags, according to the declaration.
Officials first predicted the Pearl River to reach 36 feet and crest by Tuesday, CNN earlier reported, however the river is now expected to crest sometime Monday into Monday night, emergency management officials said at a news briefing Saturday.
Barnett Reservoir General Manager John Sigmund cautioned about rising waters ahead of the crest as the water is expected to steadily rise, before slowly falling.
"It looks like we're gonna be in the floodwaters that we're seeing even today, probably well into the end of the week with then a gradual recession after that," Sigmund said.
The threat for heavy rainfall will be very localized Saturday, but much of the region has seen excessive rain over the past week, so it will not take much additional rainfall to aggravate any ongoing flooding.
A flood warning remains in effect in parts of Mississippi, including in Jackson around the Pearl River, until further notice, the National Weather Service said. A flood warning was also issued for the Strong River in Simpson County through Monday.
Widespread rainfall of 1 to 2 inches is forecast across much of the region but some locations -- including along the immediate Gulf Coast and across Florida -- could see as much as 2 to 4 inches of rain through Monday. The Florida peninsula will likely see the heaviest amounts of rainfall through the weekend.
Sigmund said the scattered and isolated rain during the week across the region is not expected to have significant impact on water levels in Mississippi.