WRAL WeatherCenter Blog

It is now 0400 1 oct 08. I was reviewing the satellite loop and noticed that there was a break from around 0150 to 0320. Could you tell me why?

Posted October 8, 2008 9:29 a.m. EDT

MIKE MOSS SAYS:       Mac,      For several weeks either side of the autumnal and vernal equinoxes, the orbit of geostationary weather satellites is such that for a short time each day the satellite moves through the Earth's shadow. During these periods, solar energy is unavailable to power the spacecraft instruments and no satellite images are captured. For this reason, you may notice our cloud loops appear to "skip" at times. The outage period can be close to three hours long very near the equinox and tapers down to near zero about 24 days before and 24 days after the equinox. Since we just had the Autumnal Equinox on Sep 22, we were still experiencing nightime outages, though they are in the process of becoming shorter now.