The appearance of a Gulfstream GIV is not something that would normally be sufficiently unusual to justify a trip out. However, this GIV was a bit unusual. It belongs to NOAA and they use it for tracking weather systems. It was operating out of Paine Field and I only got to see it once. It would launch and head out over the Pacific for six or seven hours before coming back. The return was always in the evening after dark so never an opportunity to get a shot. The rear radar installation is pretty conspicuous. However, the nose radar is also a modification. The radome is a different shape and the additional air data sensors around the radome may either be because of the change of shape or could be related to its mission.
Sadly, it departed to Florida before I could get a chance to see it on the ground. It would have been nice to see it close up (or even in halfway decent weather – not something I was given this time around) but that was not to be on this occasion.