Archive for July 6th, 2010


July 6th, 2010 1 comment

The Horizon drifter is now off the coast of the Mid-Atlantic heading for a “fork in the road”. Will it turn North and become entrained in the persistant eddy we have seen all summer, or turn South and head offshore? My bet (and hope) is South. Attached is a 24 hour average of SST from this morning. Missing data are due to clouds. Also, this is a nice shot of the coastal upwelling we have had along Delmarva and Jersey for most of the summer. I imagine folks will be taking advantage of that cool water to ease their 4th of July burns….

Horizon Drifter faces "fork in the road"


Westward motion continues

July 6th, 2010 No comments

Figure 1: Ship reports compiled by Oceanweather. Steady winds from the southeast remain the story over much of the  Gulf of Mexcio.

Figure 2: Wave response from Oceanweather.  High waves from these winds are downwind to the northwest towards the coast.

Figure 3: With the persistent winds and seas driving things to the northwest, we know what to expect.  The current measurements we have from the HF Radar are all alongshore to the northwest or west.  The Horizon Marine drifters are heading west. And so is the oil slick. The color key for the oil slick is light blue means a light oil slick, medium blue means a medium oil slick, and dark blue means a heavy oil slick. We now have a light blue slick noted just behind the Horizon Marine drifter heading west along the southern Louisiana coast.  The area of uncertainty indicated by the thin black line now extends all the way west to Houston.

Figure 4: A zoom into the main slick shows the persistent currents to the west on the inner shelf are moving the light blue slick closer to New Orleans.  The slick is also moving in on the southern side of the Mississippi Delta’s birdsfoot.

Figure 5: Same image as above but with the potential beached oil sitings turned on.  Like yesterday, you need to turn them off to reduce to label clutter so you can see the maps.

Figure 6: Zooming back out to the SABGOM model, the strong westward currents on the inner shelf persist along the coast from Florida to Louisiana.  The westward currents are slower along the Texas shelf.  Colors in the SABGOM model are the sea surface temperature.

Figure 7: Zooming out again, we now look at the HyCOM model to check the condition of the Loop Current Eddy and the Loop Current itself.  Here the color is the sea surface height, and the arrows are the surface currents.  The major Loop Current Eddy is still distinct and appears to have moved to the west.  The Horizon Marine drifters look like they are following the eastern edge of this Loop Current Eddy. A small clockwise rotating eddy around the small high in the sea surface height (yellow) is now forecast between this eddy and the Florida shelf.

Figure 8:  For those following the track of the Horizon Marine drifter on the east coast, the drifter is now well into the Gulf Stream meander and is approaching the crest. We’ll see in a couple days if it continues downstream or is ejected to the north in one of those warm filaments spinning off the top.