If you were just watching us on WINK, Kyle Jordan -- live near the Fort Myers Beach pier -- showed a couple of objects that had the look of tar balls similar to what washed ashore near Key West yesterday (several per hour there). However, it is very unlikely that these objects are at all associated with the explosion of the Deepwater Horizon in the Gulf of Mexico and the subsequent oil slick. Why?
Yesterday, it became clear that at least part of the oil slick had become involved with some of the "tentacles" of the Gulf loop current, the fast-moving stream of warm water that races from the area of the oil slick to the Keys at a 3 - 5 mph pace. A piece of the loop current, or at least enhanced surface current velocity, was located just north of the northernmost part of the current and ultimately connected with the southernmost part of the oil slick. The visibile satellite image at the top clearly shows this (and matches well with the surface current map just below).
From here, the oil slick at the surface would be pulled southward toward the Keys -- but passing a couple hundred miles west of southwest Florida. So, at the surface, that "sheen" you see in the visible satellite view entering our waters is really not a concern. Further, surface currents near the west coast of Florida are very weak and actually directed largely offshore or parallel to the coast (see the bottom image again) -- further working against the oil slick approaching our coastline. In fact, this offshore surface current was shown to exist in the late 1990s as the USGS dropped several probes in the Gulf waters and tracked them to see where oil might go in the event of a spill similar to the one happening right now. None of these probes returned to the southwest coast of Florida.
Of higher concern is what's happening underneath the water -- where we can't see. Here, water currents are much slower and all signs point to there being significant plumes of oil. Because currents are much slower below the surface of the Gulf, it would take many weeks -- if not longer -- to first observe any impacts here in SWFL. Deep water currents actually are directed onshore rather than offshore (like they are at the surface), and potentially what lingers under water is a much bigger worry than what's at the surface right now.
Because surface currents are much faster but directed away from southwest Florida and toward the Keys, it seems logical that the tar balls that washed ashore in the Keys are associated with the oil slick. What was found this morning in SWFL? Probably not so much! That said, we have had a couple days now of onshore flow but, again, with the Loop Current located so far offshore and the wind still relatively light, it still seems unlikely that tar balls from the oil slick could have ventured into our water.
Of course, there are also several variables at play that we must watch carefully -- most notably the wind. Wind can certainly augment the weak surface current and a prolonged stretch of south or southwest wind coming up from the Keys potentially could alter the future track of the oil slick.
Brian
