Klobuchar is expected to make the announcement on Sunday at an outdoor event on Boom Island, a park that juts into the Mississippi River in Minneapolis. (The projected high on Sunday is 18 degrees.) The 58-year old senator will highlight her working-class roots and bipartisan appeal in her speech, the sources close to her said, leaning on the fact that she has won widespread appeal in Minnesota, a state that nearly went for President Donald Trump in 2016.
"The people from the Heartland believe in hard work, telling it like it is, and getting things done," Klobuchar says in the invite to her event. "That's true in Minnesota where I grew up, and that's true across the border in Iowa. We have a lot to get done in the days, weeks, and months ahead."
Klobuchar's speech on Sunday will lean heavily into her Minnesota roots, including the grit that it takes to draw people to a political event in sub-freezing weather.
"I'm asking you to join us on this campaign. It's a homegrown one. I don't have a political machine. I don't come from money," Klobuchar will say according to excerpts of her prepared remarks. "But what I do have is this: I have grit. I have family. I have friends. I have neighbors. I have all of you who are willing to come out in the middle of the winter, all of you who took the time to watch us today, all of you who are willing to stand up and say people matter."
Minneapolis and the nearby Mississippi River will also play a central role in Klobuchar's speech, according to an adviser.
"There is quite a bit of, a lot of meaning behind where she is doing this," the adviser said. Klobuchar will be "thinking about how the Mississippi starts in Northern Minnesota and how it runs through the heartland and will talk about how this connects our country in so many ways."
Klobuchar will say, "The Mississippi River... all our rivers connect us... to one another. To our shared story. For that is how this country was founded, with patriots who saw more that united them than divided them."
Klobuchar will follow up her event in Minnesota with a trip to Iowa on February 21, where she will speak at the Ankeny Area Democrats Winter Banquet and Fundraiser.
Klobuchar's presidential aspirations have not been a secret to many in her home state and around Washington.
Klobuchar told reporters in early January that she was "getting close to a decision" about running for president in 2020.
"I'm continuing to talk to people about it," she said.
She told CNN in late December 2018 that it was a "big decision" because there are "a lot of different people running."
"I think you want voices from places where Donald Trump did very well," she said. "My state, for instance, he almost won in 2016, and we came roaring back in 2018. I was leading the ticket, and I believe you need people that will go not just where it's comfortable, but where it's uncomfortable and be willing to work with other people that you don't always agree with for the betterment of this country."
A Klobuchar run, according to people who have talked to her about the prospect, would cast the senator as a deal maker who is able to get things done when things need to get done. She will cast herself as the granddaughter of rural America, someone whose life was helped by a grandfather who saved money in a coffee can to send her father, who would go on to become a journalist, to college.
Klobuchar's team believes there is an opening in the Democratic primary for someone who is able to relate to voters in Iowa because of her local ties, but is also able to talk to Democrats eager to beat Trump in 2020 as well as win back Trump voters.
That is where Democrats believe Klobuchar's electoral record will factor in: The senator has consistently overperformed against other Democrats in Minnesota, winning her three terms in office by an average of 26 percentage points.
Klobuchar won re-election in 2018 with 60% of the vote visiting all 87 Minnesota counties during the campaign, including 42 that went for Trump in 2016. This win helped burnish Klobuchar's credibility with rural and lean Republican voters and will likely be the backbone of her campaign.
"She could surprise pundits here," said Matt Paul, Hillary Clinton's Iowa state director during the 2016 caucus. "She's a neighbor, has long been working to elect Democrats in Iowa and established herself as a Democrat who gets things done."
Klobuchar has a liberal voting record but is not considered as liberal as other candidates running for president or considering a 2020 run. Klobuchar does not support abolishing the Immigration and Customs Enforcement agency or Vermont Sen. Bernie Sanders' Medicare-for-All bill -- instead pushing to lower the age where people are allowed to buy into the government health care program.
Some Democrats question whether her more moderate voting record -- she supported, for example, Trump's nominations of Wilbur Ross, Mike Pompeo and John Kelly and a host of other nominees -- is left enough to succeed in a Democratic primary. According to FiveThirtyEight's congressional vote tracker, Klobuchar voted with Trump's interests 31% of the time since he took office.
Born in Plymouth, Minnesota, Klobuchar returned to her home state after attending Yale University and getting her law degree at the University of Chicago. She began her career in private practice before being elected narrowly as Hennepin County attorney in 1998. She was reelected with no competition in 2002.