Also I think you need 4 hourly obs to get the 3 hours inclusive...not sure. BDR is manned today too, but I’m not sure if they augment vis obs.
Maybe @OceanStWx knows how GYX goes about verifying it.
Criteria has always been under 1/4SM. But with automated ASOS sites without augmentation it’s damn near impossible to get obs of M1/4SM. A lot of the old manned 0SM, 1/16SM, and 1/8SM obs are seen as 1/4SM by the ASOS now.