It affected stations over a wide area of the Eastern US. The initial glitch lasted just over one minute and resulted in a diminution of signal strengths for about 5 minutes after which they returned to about the levels preceeding the disturbance. The upward shift in frequency indicates the disturbed region was moving towards me.
So, what the heck could influence the ionosphere over such a large area at the same time? Only possibility that comes to mind is a large meteor event of the fireball category but the American Meteor Society website has no report of such an occurence today. One does read about ionospheric blobs which appear spontaneously and move at high speeds, often in association with Sporatic E. Maybe with the SE season upon us more such glitches will occur.
At least I've documented my observation here and will be on the lookout for future events of this nature. It's easy to overlook the little things but they often are the most interesting.