Pilots often are fooled by widespread fog. In overrunning or warm frontal conditions, low ceilings may be so pervasive that a legal alternate will be hard to find. Oftentimes we are lulled into complacency by reports of low ceilings because the associated weather is benign. While we all would like to get into an airport that is reasonably close to our original destination, pilots should understand that it is not a good idea to expect that an alternate airport influenced by the same weather system as the destination will improve. We need to know where there is better weather -- where there is a suitable alternate -- and we should be prepared to go there when there is little hope of getting into an airport close to the destination. Oh, it is tempting to try, but the gas that gets spent on the attempt will limit an escape to better weather. As usual, the weather picture will influence our decision-making, and our management skills need to be at least as developed as our skills at flying instrument approaches.
This is a companion discussion topic for the original entry at https://www.avweb.com/flight-safety/where-will-you-go