I've waited almost a month to post this. Mostly because I've been savoring the feeling of having put together information from various sources and all on my own coming up with an explanation for an observed natural phenomenon.
Okay, really? I've waited so long to post this because one of you will probably tell me my explanation is incorrect.
I've been inordinately proud of myself, and I didn't want to pop that bubble.
So here's the deal: Several times over the past six weeks or so -- most recently two mornings ago -- I've noticed some very localized fog over Gulf waters.
In the West Delta field, one drilling rig might be completely in the clear as the sun rose, while another rig two miles away is shrouded in gray.
Of course those factors most directly impact the formation of radiation fog, which is mostly a land-based phenomenon.
Of greater concern to mariners is advection fog, or sea fog, which forms when warm, moist air moves across cooler water, causing the warm air to contract and condense.
My question was: why over here, and not over there?
One day as we were plunging into the gray, I noticed a "rip," or line of foam that denoted a current in the water. On one side, the opaque green of the nearshore Gulf; on the other, a silty brown. I thought about this, and decided that the brown stuff was Mississippi River water, floating on top of the heavier salt water.
It also occurred to me that these eddies or currents of river water were probably cooler than the surrounding Gulf water. (I could find nothing on the interwebs about river water in the Gulf, or surface water temperatures for the areas I was looking at, by the way.)
And sure enough, that fog bank started on the other side of the rip and appeared to cover only the brown water.
Did I get it right?