cylindrical shaped object with rotating display

I was leaving work after 2AM when i saw in the sky a cylinder-shaped object with a circular blue digital display with what seemed to me to be possibly Cyrillic letters that sequentially moved from left to right, like one of those displays you see on bank buildings and such.  It made a high-pitched whining noise with two tones, maybe an octave or two apart. It seemed to me to be no more than maybe 50-100 feet overhead.  It moved rather slowly and quite majestically.  
At the time I had assumed it was a weather monitor or some such.  There is an Air Force base in Tampa, so I supposed it was something to do with that, however, the unusual alphabetical characters makes me wonder what it actually was.  It seemed to be rather small, at most half the size of a Volkswagen bug. 
I'm curious to know if anyone knows what it was. 
Thank you.
Witness indicates that date is approximate.  PD