AN ACR MLG LANDED BELOW MINIMUMS.

Narrative

THE WX AT GRB DETERIORATED FROM 1/2 MI VISIBILITY TO 1/4 MI WHILE WE WERE ENRTE TO GRB. I NOTIFIED DISPATCH OF THE CHANGE AND THAT GRB IS BELOW MINIMUMS (1/2 MI IS REQUIRED). DISPATCH THEN CONTACTED GRB TWR AND WAS TOLD THAT GRB TWR VISIBILITY IS 1/2 MI. THIS WAS RELAYED TO ME BY DISPATCH AND SO WE CONTINUED TO GRB. DURING OUR ILS APCH TO RWY 36 AT GRB; WE WERE ADVISED THAT THE WX WAS 500 OVCST 1/4 SF BUT THE TWR IS RPTING A VISIBILITY OF 1/2 MI. WE LANDED ON RWY 36 BASED ON THE RPTED TWR VISIBILITY 1/2 MI. AFTER RETURNING TO DTW; WE WERE ADVISED THAT GRB TWR HAD RPTED US FOR LNDG WHILE THE VISIBILITY WAS BELOW MINIMUMS. WE LATER LEARNED THAT THE TWR VISIBILITY BEING RPTED WAS AN INFORMATIONAL REMARK AND SERVED NO PURPOSE OTHER THAN TO CAUSE CONFUSION. SUPPLEMENTAL INFO FROM ACN 262806: I HAD GND CONTACT AT ABOUT 1500 FT AGL AND HAD THE RWY LIGHTS IN SIGHT AT ABOUT 1 MI. WHEN THE WX AT THE DEST IS FLUCTUATING; CONFLICTING RPTS ADD TO THE BURDEN OF FLYING A 2 CREW MEMBER ACFT. A SIMPLE ADVISORY STATEMENT THAT THE LNDG RWY IS BELOW MINIMUMS WOULD HELP TO CLARIFY THE ACTUAL CONDITIONS.