The associated press has an informative article on the state of mind of Puerto Rican voters. They don’t anticipate a large turnout for a variety of reasons. One of the most important is expressed here:

Islanders typically are reluctant to become entangled in mainland politics and now that most of the suspense is gone, it’s questionable whether the forecast for 500,000 Puerto Ricans to vote will hold up.

“Traditionally people in Puerto Rico see the primaries as something far removed from their political reality,” said Angel Rosa, a political science professor at the University of Puerto Rico at Mayaguez. “They don’t see this primary as any kind of opportunity to send a message to the United States.”

…Charlie Hernandez, a lawmaker from the governor’s party that favors maintaining the island’s commonwealth affiliation with the U.S., said the island has traditionally asked Washington to stay out of its business and should sit out the U.S. election.

“I think there are other ways to influence Washington without converting Puerto Rico into an appendage of North American politics,” he said.

The only reason any of this really matters is that Team Clinton wants to lay claim to having won the popular vote and they can’t do that unless she wins Puerto Rico in a landslide and more than a million voters show up. The most inclusive reasonable count of the popular vote (including Florida and all caucus states, but not Michigan) has Obama with a popular vote lead of 274,000. He’ll probably add to that by winning South Dakota and Montana. So, he probably has a 300,000 vote margin outside of Puerto Rico. To net 300,000 votes out of Puerto Rico the Clintons would need to win 65-35 if a million voters turned out. If only 500,000 voters turn out, then she would need to win 80-20. And that is not going to happen. Per the AP’s reporting, it now appears unlikely that even 500,000 will turn out. So I think the popular vote fantasy will not materialize.