With another 1000kg QF could easily have gone to BHI after missing out at MIA...
I think an earlier post said that the pavement strength of BHI is inadequate for a B737. MIA is PCN 32, BHI is PCN 15. I don't fully understand the B737 requirements, but prima facie it looks to me that the previous poster was correct and YBHI was not a viable alternative.
If you accept that they required an alternate that was closer than ML, then MIA was the only option.
I think there is also a potential argument that busting minima at MIA is safer than at AD
My reading of the forecasts is that they went from PROB30 Fog to Fog below minima in one step. Really? I also suspect that the TAF was still saying PROB30 Fog AFTER the fog had formed.
An accurate forecast as little as 1 hour ahead may have changed this event.
A previous poster suggested that the BOM gets ground observations from a BOM person at the airport. One of my concerns / questions about the BOM is whether it has become primarily a 9-5 Mon - Fri organisation. Most of the decisions for this flight occurred before 9am. Was the BOM guy actually at work and providing observations?