Sabato isn't normally someone I'd link to but this seems right. One race at a time the Democrats are competitive for each of several Senate races, but it's an uphill struggle to win enough for them to reach 51.
centerforpolitics.org/crystalball/...
centerforpolitics.org
We are making three Senate rating changes this week, all in favor of Democrats. North Carolina moves to Leans Democratic, and Alaska and Ohio are now Toss-ups.