In Georgia, the black share of the electorate so far is 30 percent. Of those black voters, 93 percent voted for Michelle Nunn (D) and 6 percent voted for David Perdue (R), according to the exit polls. That 30 percent vote share is actually below the 2010 mark (see chart), when African Americans made up 32.4 percent of the vote in the Peach State.

Among whites, Nunn got 27 percent of the vote, with 69 percent going to Perdue. According to a study by the Joint Center for Political and Economic Studies, Nunn needed to get closer to 40 percent to win an outright majority and avoid a runoff. And Democratic pollsters were looking for a share of black voters closer to 2012 and 2010.

Of course, preliminary exit poll results on the size of groups in the electorate should be taken with a grain of salt, as they've historically over-estimated the size of the minorities in the electorate compared to other sources.

North Carolina, meanwhile, has so far seen something of a jump in the typical midterm turnout for African Americans. According to exit polls, blacks made up 21 percent of the vote, matching their 2008 presidential-year numbers, and a slight bump from 2010. Roughly 95 percent of those black voters cast ballots for Kay Hagan (D), with 3 percent going for Thom Tillis (R).

The white vote so far is 74 percent of the electorate, with 35 percent going to Hagan and 59 percent going to Tillis. As we've said before, for Democrats to be competitive in these Southern states, they need to win a share of white voters that approaches 40 percent, along with swelling the black vote. Hagan seems on-pace to putting together a multiracial coalition that mirrors Obama's -- again, according to the early numbers.

The numbers also reveal that Republicans have not moved the needle in attracting any significant number of African American voters, despite more robust outreach efforts by the Republican National Committee.

These are preliminary results from exit polling conducted among voters interviewed as they exited voting places across the country on Tuesday, as well as with early voters reached by telephone. The exit poll is conducted by Edison Media Research for the National Election Pool, the Washington Post and other media organizations. Preliminary results will change somewhat through the night as the exit poll is adjusted to align with vote results. Typical characteristics have margin of sampling error of plus or minus 2-3 percentage points.