Intermittent thunderstorms brought well over an inch of rain to most parts of the Twin Ports overnight Sunday — with a promise for more rain in the forecast as storms descended on the region and figured to last into the week.

The National Weather Service in Duluth explained why the storms seemed to refuse to leave.

“We have a frontal boundary that is stalling out,” meteorologist Kirsten Chaney, of the National Weather Service in Duluth. “The storms are forming along this boundary and it is moving slowly, just staying overhead. Luckily, most of the environment is not conducive for severe weather.”

Entering Sunday, Duluth had trailed its normal precipitation for June by 1.43 inches with 2.65 total inches of rain for the month, according to preliminary data from the National Weather Service.

The weather service did issue temporary storm warnings for multiple areas in the Northland on Sunday morning. Storm warnings for central St. Louis County on the Iron Range, western Carlton County, places along U.S. Highway 2 in Itasca County, and Big Sandy Lake, near Tamarack, called for 60 mph winds and large hail. Those storms seemed to pass without serious incidents.

Official spotters with the National Weather Service mostly reported bouts of heavy rain throughout the region, but had little to say about hail or wind damage.

The intermittent thunderstorms that hit Sunday overnight brought ample rain.

The western portion of Duluth received 1.23 inches of rain by Sunday morning, according to the gauge at the Western Lake Superior Sanitary District, which recorded inch totals of 1.60 in Hermantown, 1.19 in Proctor, 1.26 in Pike Lake. 1.58 in Rice Lake, 1.45 in the Endion neighborhood of Duluth and 1.35 in Scanlon, 20 miles south of Duluth along Interstate 35.

Much of the same type of weather remained in the forecast for Monday and beyond as thunderstorms remained in the works. A severe storm threat was low, the National Weather Service said, but heavy rain was in the offing for parts that would be affected by scattered storms.

Counties throughout the region, including northwestern Wisconsin, were to be on the lookout for a “complex of storms” on Monday and, depending on persistence, by Tuesday morning storms “may cause locally heavy rain leading to flooding,” the National Weather Service said.

Throughout Sunday, rain was spotty in and around Duluth. Lake freighters were moving across Lake Superior, which was choppy but manageable. In the city, only a few customers remained without power Sunday afternoon, according to Minnesota Power outage maps.