Rain will continue on Friday in the Billings area before tapering off in the evening, but the weekend will be mostly sunny and drier.
The National Weather Service also said rainfall will continue over a widespread area of Eastern Montana and the Dakotas on Friday.
Some areas of the eastern plains may receive another half to three quarters of an inch of precipitation, which will aggravate flooding along small creeks and low lying areas across southeast Montana and in Musselshell County.
Many small streams and rivers will be rising to bankfull levels, with some even overflowing their banks. Rain also is expected to continue causing debris flow in areas burned by wildfires last year.
Strong northwest winds also will continue across the region on Friday with the strongest winds forecast for Sheridan County, Wyo. and southern Big Horn County in Montana where gusts up to 60 mph are possible.
The high for Billings on Friday will be about 57 degrees with a 90 percent chance of precipitation. Westerly winds will be up to 31 mph with gusts as high as 44 mph. The low will be about 45 degrees with rain likely before midnight.
Saturday will be mostly sunny with a high near 67 degrees and westerly winds up to 10 mph. The low will be about 47 degrees with partly cloudy skies. Sunday will be partly sunny with a high of 77 degrees and a low of 52 degrees.
Since the slow-moving low-pressure system moved in on Sunday, 2.13 inches of precipitation have been recorded at the Billing Logan International Airport, said Tom Frieders, a NWS meteorologist. Some areas have seen higher amounts, with a few reports of closer to 3 inches, he said.
East of Billings and southeastern Montana have seen between 4 inches and 5 inches of rain since Sunday, Frieders said.
Total precipitation of 1.85 inches in Miles City on Thursday broke the previous calendar day record of .98 inches set in 1978, Frieders said. "That particular record was shattered," he said.
There have been reports of minor flooding and poor road conditions especially in rural areas but "no significant impacts at this point," Frieders said.
The Montana Department of Transportation reported flooding in Custer County on Sand Creek, which sent water running over Highway 489 at mile marker 13.5 with up to three feet of water reported in the westbound lane.