GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing.
Dense Fog developed over the upper Midwest on Monday morning, 23 October 2017, and Advisories were issued as shown below. GOES-R IFR Probabilities are now being created using GOES-16 data, those data are now available at this link. The uniformity of the IFR Probability fields shown above over WI suggest that high-level clouds are present, and the GOES-16 satellite could not therefore view the fog/stratus near the ground: only Rapid Refresh data were used to create GOES-R IFR Probability values.
GOES-R IFR Probability fields available to NWS Field Offices via LDM are still being computed with GOES-13 and GOES-15 data. When GOES-16 becomes operational as GOES-East at 75.2º W Longitude, planned for December, IFR Probabilities available through the LDM will be created with GOES-16 and GOES-15 data. The switchover will happen when GOES-16 becomes operational.