You can bet that the Democrats didn't want to hear this.

An analysis of early voting patterns in seven states shows that Republican enthusiasm is putting a damper on the Democrats' dream of a wave election.

NBCNews:

Republican-affiliated voters have outpaced Democratic-affiliated voters in early voting in seven closely watched states, according to data provided by TargetSmart and independently analyzed by the NBC News Data Analytics Lab.

GOP-affiliated voters have surpassed Democratic-affiliated ones in early voting in Arizona, Florida, Georgia, Indiana, Montana, Tennessee and Texas, the data showed.

Only in Nevada have Democratic-affiliated voters exceeded Republican-affiliated voters so far in early voting, according to the data.

Six of those states feature close races for the Senate.  Districts in Georgia, Florida, and Texas are pivotal to the Democrats' plans to take over the House. 

The latest data suggests robust enthusiasm among early Republican voters that could put a dent in Democratic hopes for a "blue wave" in next month's midterm elections.

Republicans typically dominate early voting by absentee ballots, while Democrats tend to have the advantage with in-person early voting.  So, for example, the entire early voting picture in Florida, which has yet to begin in-person voting, is incomplete.

The Republican surge is especially noticeable in Arizona, Florida, and Indiana:

In Arizona – where two members of the House, Democrat Kyrsten Sinema and Republican Martha McSally, are in a neck-and-neck contest to fill retiring Republican Jeff Flake's Senate seat – 44 percent of early voters had a Republican affiliation, compared to 33 percent who had a Democratic affiliation.  Twenty-three percent of early voters were not affiliated with either major party, and thus grouped as "other" in NBC News' partisan analysis.

In Florida – where Democratic Sen. Bill Nelson is running for re-election in a tight race against Republican Gov. Rick Scott – 44 percent of early voters had a Republican affiliation, versus 38 percent who had a Democratic affiliation and 18 percent who were not affiliated with either party.

In Indiana – where Democratic Sen. Joe Donnelly is facing a re-election challenge from Republican businessman Mike Braun – 51 percent of early voters had a Republican affiliation, compared with 39 percent who had a Democratic affiliation and 10 percent who were not affiliated with either party.

Democrats are enthused as well, but the notion that Republicans are so disheartened that they won't vote appears to have gone by the boards.

The election is still two weeks away, and there's a potential storm brewing on the border, with thousands of people making their way through Mexico, vowing to crash the U.S. border.  This may be a boost for Republicans if, as expected, the president stands firm.  There could also be surprises in local races, like the news that Georgia's Democratic gubernatorial candidate, Stacey Abrams, helped burn a state flag in 1992.

With so many races so close, it won't take much to tip a contest one way or another.  But the early voting by Republicans will probably force Democrats to walk back their predictions of a sweep and to tone down expectations of a "blue wave."