Oil enters the Loop Current and is headed to the Florida Keys
Satellite imagery today from NASA's MODIS instrument confirms that a substantial tongue of oil has moved southeast from the Deepwater Horizon oil spill and entered the Gulf of Mexico's Loop Current. The Loop Current is an ocean current that transports warm Caribbean water through the Yucatan Channel between Cuba and Mexico. The current flows northward into the Gulf of Mexico, then loops southeastward just south of the Florida Keys (where it is called the Florida Current), and then along the west side of the western Bahamas. Here, the waters of the Loop Current flow northward along the U.S. coast and become the Gulf Stream. Once oil gets into the Loop Current, the 1 - 2 mph speed of the current should allow the oil to travel the 500 miles to the Florida Keys in 10 - 20 days. Portions of the Loop Current flow at speed up to 4 mph, so the transport could be just 4 - 5 days. It now appears likely that the first Florida beaches to see oil from the spill will be in the Lower Florida Keys, not in the Panhandle.
Figure 1. Satellite image of the oil spill taken at 12:40 EDT Monday May 17, 2010. The location of the Loop Current is superimposed. Image credit: University of Wisconsin and NASA.
Why is oil getting into the Loop Current?
The winds over the oil spill location are offshore out of the northwest today, and offshore winds will continue intermittently through Wednesday, which should allow a substantial amount of oil to enter the Loop Current. The major reason oil is moving southwards is because of the instability of the currents in the Gulf of Mexico. The Loop Current is not a stable feature, and tends to surge northwards and southwards in a chaotic fashion, and in response to changes in the prevailing winds. Over the past week, chaotic behavior of the Loop Current and a clockwise-rotating eddy just to its north, just south of the oil spill location, have combined to bring a current of southward-moving surface water to the oil spill location. As strong on-shore winds from the southeast slackened this past weekend, oil has been drawn southward into the Loop Current. The latest NOAA trajectory forecasts failed to anticipate the movement of the oil into the Loop Current. The latest surface current forecasts from NOAA's HYCOM model show that oil could continue pouring into the Loop Current for most of the rest of the week. It is highly uncertain how diluted the oil might get on its voyage to northwestern Cuba and the Florida Keys this week, but the possibility for a major ecological disaster in the fragile Keys ecosystem cannot be ruled out. Southeast to east winds of 10 - 15 knots are expected to develop late this week and extend into early next week, which may be strong enough to impose a surface current that will shut off the flow of oil into the Loop Current by Friday or Saturday.
Figure 2. Forecast made at 8pm EDT Sunday May 16, 2010, of the Gulf of Mexico currents by NOAA's HYCOM model. A persistent southward flowing surface current is predicted to occur this week between the oil spill location (red dot) and the Loop Current. Image credit: NOAA.
Likely areas of impact
Based on a study of 194 floating probes released into the Northeast Gulf of Mexico during a 1-year study in the 1990s (Figure 3), the west coast of Florida from Tampa Bay southwards to the Everglades is at minimal risk of receiving oil from surface currents. There is a "forbidden zone" off the southwest Florida coast where the shape of the coast, bottom configuration, and prevailing winds all act to create upwelling and surface currents that tend to take water away from the coast. This study implies that the greatest risk of land impacts by surface oil caught in the Loop Current is along the ocean side of the Florida Keys, and along the coast of Southeast Florida from Miami to West Palm Beach. Eddies breaking away from the Gulf Stream would also likely bring oil to northwest Cuba, the western Bahamas, and the U.S. East Coast as far north as Cape Hatteras, North Carolina, though at lesser concentrations. Southwest Florida cannot rest entirely, though--the "forbidden zone" is only true for surface waters, and there is onshore flow below the surface. Since recent ship measurements have detected substantial plumes of oil beneath the surface, southwest Florida might be at risk if one of these plumes gets entrained into the Loop Current. These subsurface plumes were also detected by current probes launched into the oil spill on May 8 by one of NOAA's hurricane hunter aircraft, according to one scientist I spoke to at last week's AMS hurricane conference. There are plans for the Hurricane Hunters to go out again tomorrow and drop more probes into the spill to attempt to get a better handle on where the oil is and where the currents are taking it.
Figure 3. Paths of 194 floating probes released into the yellow-outlined area in the northeast Gulf of Mexico between February 1996 and February 1997 as part of a study by the Mineral Management Service (MMS). The probes were all launched into waters with depth between 20 and 60 meters. Image credit: Yang, H., R.H. Weisberga, P.P. Niilerb, W. Sturgesc, and W. Johnson, 1999, Lagrangian circulation and forbidden zone on the West Florida Shelf, Continental Shelf Research Volume 19, Issue 9, July 1999, Pages 1221-1245 doi:10.1016/S0278-4343(99)00021-7
When will a Loop Current eddy break off?
Every 6 - 11 months, the looped portion of the Loop Current cuts off into a clockwise-rotating ring of water that then slowly drifts west-southwest towards Texas. When one of these rings breaks off at the peak of hurricane season, it provides a source of heat energy capable of providing fuel for rapid intensification of any hurricanes that might cross over. The Loop Current is not predicted to shed an ring over the next month, as predicted by the latest 1-month forecast from the U.S. Navy. However, the last eddy broke off in July of 2009, ten month ago, and it is unusual for the Loop Current to go more than eleven months without shedding an eddy. I expect we'll see the Loop Current shed an eddy in July or August, just in time to pose the maximum threat for hurricane season. According to an interesting February 2004 article published by offshore-engineer.com, reliable forecasts of these currents and eddies are not available yet. Keep in mind that surface currents are largely driven by winds, and wind forecasts are not reliable out more than about 10 days.
References
Yang, H., R.H. Weisberga, P.P. Niilerb, W. Sturgesc, and W. Johnson, 1999, Lagrangian circulation and forbidden zone on the West Florida Shelf, Continental Shelf Research Volume 19, Issue 9, July 1999, Pages 1221-1245 doi:10.1016/S0278-4343(99)00021-7.
Oil spill resources
NOAA trajectory forecasts
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Surface current forecasts from NOAA's HYCOM model
HYCOM ocean current forecasts from LSU
Jeff Masters
Reader Comments
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Thanks.interesting read
;)
Don't we all wish that?
It's only May! The season hasn't even started yet! :o)
Oh.. that's farthest from the truth lol..
how's it going la?
And anomaly charts as well.
Everythings well. Busy as usual, u know. How about yourself?...Westerlies looks like they're hangin strong for now..lots to look at and learn every season for sure
Pretty good actually! enjoyed the rain we finally got in FL at least in my area. Humid!
Yea, the westerlies look strong but they're actually below average for this time of year.. and especially compared to last!
Well.. outta hit the sack. Night all..
At T-14 days and counting, this weather underground control. ;-)
May 16, 2005
Named Storms: 12-15
Hurricanes: 7-9
Major Hurricanes: 3-5
Thanks for the update on ur weather too. Finally got rain here, but need more.
K, see ya
Yes i know what you mean,enjoy!
Katla Earthquake May Presage Next Volcanic Explosion
or this:)
LOL
OMG eddye you live there!
You forgot Kendall =-x
it's not the BP well head, where I wanna shove that volcano...
We can have big variations between two locations close each other, even on a small island. Today 40mm were recorded in the french side's main town, while only 11mm fell at SXM airport (duch side).
firefox 4.0 beta
and window live wave 4 beta
all so window 8 later in the year
I really wish we could, unfortunately, we are helpless at this point :(
I think it is more than an oil problem now! What we are injecting into the slick, in mass, is really an unknown....
I don't like it.......
lol
I understand! When I read today's blog entry, my first thought was to have all 116.000 BP employees to don oil proof life-jackets and use them as human containment barriers.
Then I thought, the majority of employees are innocent. Then I thought things, God forgive me, I will not metion. Has to do with the BP Board of Directors, crude oil and a controlled burn.
Yes, I AM PISSED at BP, real MAD. They knew there was a problem, they did nothing about it, and now we're going to have crude oil from LA to SC!!!
PS, we should sue the poop out of BP and bankrupt them, then oil companies will think twice before pulling another stunt!!
The tropical Indian Ocean is on fire, like between 85-90F. And there is a cyclone forming in the Bay of Bengal, the first of their season, forecasted to be an 80KT/92 MPH TC!!
It's the first time I've ever seen it originate from the west. Could this be our first La Nina Mokiki(I know The Peruvian Current probably won't let it happen but what if)?
Not sure if a Modiki La Nina is possible?!? However last year the Indian sub-continent only had a few cyclones. I fear this year, things will be ugly for, as I fear the Tropical Atlantic, when it gets started will be very ugly!!
I want the CEO to go there, with his children and grandchildren, and tell them "This is my livelihood. This is what I've done to your world. Long after I am dead, my legacy will live on for decades."
may they rot, as our gulf is doing.
My plan is to drain BP dry, make them clean up EVERYTHING. Let'um spend a few billion dollars on the cleanup and a few billion more in paying the claims.
Let the other "oil giants" sit back and watch. MAYBE they will learn something.
It will take several years to get the GOM back to normal!!!
It's nothing special. Lots of ENSO transitions start in the central Pacific. "Modoki" is not a new kind of El Nino or La Nina, it is simply a different location of the equatorial pacific warm/cold pool. The cold water will spread to the east in time.
Monsoon depressions like this take a long time to develop, but when they finally organize and get named, there's usually no stopping them, and this case is no different. Steady intensification should continue until landfall somewhere in east India in 2-3 days.
Actually, on 2nd thought, that was based off of the JTWC forecast, but upon further analysis, landfall could occur within 24 hours on the storms's current track and speed. The JTWC and the GFS seem to expect an upper shortwave currently over Afghanistan to deepen over India and recurve the cyclone prior to reaching the coast, but this doesn't seem likely based on satellite loops. The shortwave looks too late to me. We shall see, but the current course of the storm would take it to the coast within 24 hours, and this would spare India what would be a much stronger storm should it stay over water any longer.
hurricane season has not even started
That comment was clearly satirical.
Upper-level westerlies have been stronger than normal across the tropical Atlantic for the last week increasing wind shear, but the week before that saw very much below-normal wind shear due to weak westerlies.
Overall, the month of May so far has seen anomalous easterlies in the upper levels, which results in less wind shear than normal. This was the case in April as well.
All winter long, wind shear in the tropical Atlantic and Caribbean has averaged below normal. The current up-tick is one of the spikes that we are expected to see from time to time. Wind shear goes up and down just like everything else.
Overall, wind shear is on schedule, and judging the season before it even starts isn't a great idea.
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