I've been thinking about this. There are too many confounding factors here to draw any firm conclusions. The weather was awful, and Trump's victory was such a foregone conclusion that the turnout wasn't that important.
It's interesting information, but is it enough to tell us anything? More states would provide a clearer picture, but as the field narrows with each successive primary, the incentive for turnout likewise decreases (presuming, maybe incorrectly, that lots of Trump voters aren't that invested in downticket races).
The silver lining to depressed turnout for Trump (beyond him not becoming president of course) might be a Senate map that is more in play than currently projected.