ACR WDB MADE A TKOF FROM DTW IN WX BELOW NOTAMED MINS BUT WELL ABOVE NORMAL RWY MINS.

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WE WERE 48 MINS LATE OFF THE GATE DUE TO DEICING. WE TAXIED THE LENGTH OF RWY 3L AND WERE TOLD TO HOLD SHORT. A DISCUSSION ABOUT A NOTAM THAT GAVE TKOF MINS OF 300 FT AND 1 MI (WHICH WAS READ TO US BY AN OFF DUTY PLT) INDUCED ME TO ASK THE TWR FOR THE PREVAILING VISIBILITY; WHICH WAS '2 VARIABLE TO 3 MI IN LIGHT SNOW AND FOG.' WE WERE THEN INSTRUCTED TO RPT THE PASSING OF A LNDG WDB Y WHICH WE DID. WE WERE THEN CLRED INTO POS TO HOLD. I NEVER SET THE BRAKES AS WE WERE 'CLRED FOR TKOF RVR ON 3L 3500 FT IN BLOWING SNOW AND FOG.' I WOULD SEE APPROX HALF THE LENGTH OF THE RWY WITH GOOD VISIBILITY TO THE SIDES WITH THE FIRE HOUSE BARELY VISIBLE. I SAID NOTHING BUT GAVE CTL OF THE PLANE TO THE COPLT FOR THE TKOF AFTER ASSURING MYSELF OF 'LCL CONDITIONS' SUFFICIENT TO STAY ON THE CTRLINE. I BELIEVED THE LNDG WDB Y HAD CAUSED THE SUDDEN DETERIORATION. THE TKOF WAS UNEVENTFUL WITH IMPROVING VISIBILITY THROUGH OUT. I WAS INSTRUCTED TO SWITCH TO DEP BUT BEFORE I WAS ABLE TO I HEARD THE TWR SAY TO LNDG TFC 'THE VISIBILITY HAD DROPPED TO 1600 FT RVR.' MY CONCERN IS DOES 'LCL CONDITIONS' OVERRIDE A NOTAM FOR TKOF MINS? THE RWY WAS COVERED WITH 1/2 INCH LIGHT SNOW AS WE TAXIED PARALLEL TO IT. SUPPLEMENTAL INFO FROM ACN 200113. DO REMEMBER VISIBILITY BEING VERY GOOD AS I COULD SEE QUITE FAR DOWN THE RWY. IN RETROSPECT; I BELIEVE THE MOMENTARY REDUCED VISIBILITY WAS PROBABLY CAUSED BY THE LNDG WDB Y WITH REVERSE THRUST KICKING UP THE LIGHT SNOW.