Former New Mexico Republican Party Chairman Allen Weh will officially launch a bid against Sen. Tom UdallTom UdallOregon senator takes center stage in Democratic filibuster debate Bipartisan bill seeks to raise fees for public lands drilling OVERNIGHT ENERGY: Haaland courts moderates during tense confirmation hearing | GOP's Westerman looks to take on Democrats on climate change | White House urges passage of House public lands package MORE (D-N.M.) on Thursday, according to the Santa Fe New Mexican.

Weh, a businessman who finished second in a five-way gubernatorial primary behind New Mexico Gov. Susana Martinez (R) in 2010, will announce his candidacy via Web video. He's long been expected to run for the seat.

Udall is viewed as safe in the Democratic-leaning state. But Weh has the ability to self-fund much of his campaign — he spent $1.6 million of his own money in his race against Martinez — and could force Udall to spend more money than he otherwise would have had to.

Libertarian-leaning Republican attorney David Clements is also in the race.