Simultaneous Nadir Overpasses (SNOs) between GOES-15 and NPP
TLE Epoch: 2017 12 20.  Predictions up to the next  14.0 days:

     Date     Time(GOES-15)   GOES-15 Lat/Lon  NPP Lat/Lon    Distance(km)  Time Diff(sec)
 12/20/2017   22:18:11   (   0.02,-135.34) (   0.54,-133.04)  261.30                80
 12/22/2017   10:37:19   (  -0.04,-135.39) (   0.63,-138.31)  333.48                80
 12/23/2017   10:21:13   (  -0.03,-135.38) (  -0.36,-133.78)  181.88                80
 12/24/2017   22:40:28   (   0.04,-135.28) (  -0.83,-139.08)  432.97                80
 12/25/2017   22:24:24   (   0.04,-135.27) (   0.22,-134.55)   81.92                80
 12/28/2017   10:27:21   (  -0.04,-135.29) (  -0.04,-135.29)    0.43                75
 12/30/2017   22:27:56   (   0.04,-135.16) (  -0.15,-136.05)  101.40                80
 12/31/2017   22:11:50   (   0.03,-135.13) (   0.84,-131.51)  412.28                80
 01/02/2018   10:30:57   (  -0.04,-135.15) (   0.33,-136.78)  185.79                80
 01/03/2018   10:14:52   (  -0.03,-135.12) (  -0.67,-132.25)  327.64                80