Supersonic clouds

The dates and time are purely estimated. However the incident is still real 24 or so years later.
I was a radar operator in the Royal Navy and at that time I was based on an aircraft carrier. We were doing an exercise in and around the carribean sea when I was looking at the air plot (air radar display) and assisting the fighter controller complete a search with a couple Phantom fighters and a Gannet aircraft..
Everything was ok and very quiet and the exercise was going through a quiet period that was until on the long range plot I saw, what could only be discribed as a very large cloud about 80-100 miles in diameter travelling at about 750-900 miles an hour.
I had always had some very good reports and complements about my accurate relative valocity calculations up to that date and thereafter. However, I never for got that incident and the ridicule afterwards even by senior officers who witnessed what I saw...When I reported it I was told it was nothing and to forget it and get on with the task in hand.
I am twenty something years older now and live in Northern ((deleted)) with my wife. I know what I saw and I was right in my calculations, hence to say I never saw anything like it again… Except that is, when I saw the movie Close encounters 2-3 years later and then Independence day in the mid ninties… Often wonder if what I saw in my radar display was real or just a glitch but what I do know it travelled across my screen from 020 to 190 (nne to ssw) in a matter of minutes that would be about 4-500 miles…
 If anyone has had a simular experience I would love to here about it!!
Date is approximate.  PD