With nationwide blood donations in June 50,000 units short of expectations, the American Red Cross is asking folks in the Philadelphia area to take a break from their summer plans, roll up a sleeve, and give blood.

That message is nothing out of the ordinary for frequent blood donors.

Mike Southerton, a Philadelphia School District English teacher who's donated blood three times this year, says that ever since he gave blood for the first time several months ago, he can count on personal phone calls reminding him to give again exactly eight weeks after his last pint.

"At first I was like, 'Oh my God, they just keep, like, harassing me over and over and over again for blood,'" he said.

But on one of those first calls, Southerton found out he has Type O blood, meaning his blood is safe for every possible recipient.

"That actually gave me a much greater sense of purpose in doing it," Southerton said.

The American Red Cross usually experiences a drop in blood donations throughout the summer, as vacation plans take people away from workplaces and schools where they might otherwise donate.

The recent dip in donations is still slightly atypical. Anthony Tornetta, a Red Cross spokesman for New Jersey and Pennsylvania, says this week's alert follows an emerging trend.

"Over the last two years, we've noticed that June has a more significant decline than July and August," he said.

Tornetta noted that the agency is also trying to catch up after low donations following the midweek Fourth of July holiday.

The American Red Cross experiences a similar slump during the winter holidays each year.