I believe democrats will have higher turnouts as well of certain demographics, mainly because millenials, their biggest voting block, are voting at levels higher then baby boomers, gen X or even greatest generation at their average ages.
However, I think the republican base is also very energized, both due to the success of trump's administration, and the ever growing insanity of the Far left, which the DNC seems to be embracing, much to the chagrin of moderate democrats.
It wouldnt surprise me to see both the house and senate going further red, simply because the democrats are so busy splintering. They are either pushing candidates that have made complete asses of themselves on twitter over trump, practically writing the oppositions attack ads for them, or are promoting radical left wingers that alienate anyone to the right of stalin. The rabidness of their supporters, and the delusional hysteria they have been pushing through the media, is absolutely demoralizing to the moderate left. If numbers in other states reflect new york, the democrats will be in big trouble in november.
The democrats will see a higher turnout of far left voters, but it wouldnt surprise me if the moderate voters were absent.